Photon Activation Analysis [Reprint 2011 ed.] 9783110864144, 9783110072501

Table of contents :
Preface
1 Activation analysis - the general principle
1.1 Introduction and history of photon activation analysis
1.2 Types of nuclear reactions used for activation analysis
1.3 Calculation of the induced activity
2 Photonuclear reactions
2.1 General features of photonuclear reactions
2.2 (γ, γ-)-reactions
2.3 Photoneutron reactions
2.4 Yields of photonuclear reactions
2.5 Radionuclides produced through photonuclear reactions
3 Activating radiation sources
3.1 Radionuclide sources
3.2 Electron accelerators
3.3 Production and physical properties of bremsstrahlung
3.4 The bremsstrahlung converter as a neutron source
3.5 Typical irradiation facility
3.6 Conclusion
4 Photon spectrometers
4.1 Detectors
4.2 Photon counting electronics
4.3 The spectrometers used for the present work
4.4 Preparation of semiconductor photon spectrometers for analysis
5 Properties and yields of radionuclides produced through photonuclear reactions
5.1 General remarks
5.2 Experimental conditions
5.3 Data tables
6 Analytical application
6.1 Light element analysis
6.2 Single and multielement analysis (Z greater than 10)
Bibliography
Subject index

Citation preview

Photon Activation Analysis

Christian Segebade Hans-Peter Weise George J. Lutz

Photon Activation Analysis

w DE

G Walter de Gruyter · Berlin · New York 1988

Christian Segebade Dr Ing. Hans-Peter Weise Bundesanstalt für Materialprüfung Unter den Eichen 87 D-1000 Berlin 45 Föderal Republic of Germany George John Lutz, Ph. D. National Bureau of Standards Washington D. C. USA

Library of Congress Cataloging in Publication Data

Segebade, Christian, 1939Photon activation analysis. Bibliography: p. Includes index. 1. Radioactivation analysis. I. Weise, Hans-Peter, 1942 II. Lutz, G. J. (George John), 1933 . III. Title. QD606.S44 1987 543'.0882 87-15602 ISBN 0-89925-305-9 (U.S.)

CIP-Kurztitelaufnahme

der Deutschen

Bibliothek

Segebade, Christian: Photon activation analysis / Christian Segebade ; Hans-Peter Weise ; George Lutz. - Berlin ; New York : de Gruyter, 1987. ISBN 3-11-007250-5 NE: Weise, Hans-Peter:; Lutz, George:

Copyright © 1987 by Walter de Gruyter & Co., Berlin 30. All rights reserved, including those of translation into foreign languages. No part of this book may be reproduced in any form - by photoprint, microfilm or any other means - nor transmitted nor translated into a machine language without written permission from the publishers. Printing: Gerike GmbH, Berlin. Binding: Lüderitz & Bauer GmbH, Berlin. Printed in Germany.

Table of contents

1 1.1 1.2 1.2.1 1.2.2 1.2.3 1.3

Preface Activation analysis - the general principle Introduction and history of photon activation analysis Types of nuclear reactions used for activation analysis Neutron activation Activation with charged particles Photon activation Calculation of the induced activity

1 3 3 6 6 8 9 13

2 2.1 2.1.1 2.1.1.1 2.1.1.2 2.1.1.3 2.1.2 2.2 2.3 2.3.1 2.3.3 2.4 2.5 2.5.1 2.5.2 2.5.3 2.5.4

Photonuclear reactions General features of photonuclear reactions The absorption of photons by nuclei Excitation of individual nuclear levels Giant dipole resonance Interaction with high energy photons The deexcitation of the nucleus after absorption of a photon (γ, y-)-reactions Photoneutron reactions (γ, 2n)- and (γ, 3n)-reactions Reactions with emission of charged particles Yields of photonuclear reactions Radionuclides produced through photonuclear reactions Light target elements Medium and heavy elements Fissile nuclei Neutron-induced reactions

19 20 20 21 22 26 26 27 31 43 43 46 51 51 51 53 54

3 3.1 3.2 3.2.1 3.2.2 3.2.2.1 3.2.2.2 3.2.3 3.2.4

Activating radiation sources Radionuclide sources Electron accelerators Van de Graaff generator Linear accelerator General description The accelerator used in the present work Betatron Microtron

57 57 59 60 61 62 65 68 70

VI

3.2.5 3.3 3.3.1 3.3.2 3.4 3.5 3.6

Other electron accelarators Production and physical properties of bremsstrahlung The spectrum of the bremsstrahlung photons (X-ray spectrum) Bremsstrahlung efficiency The bremsstrahlung converter as a neutron source Typical irradiation facility Conclusion

72 74 74 78 84 89 92

4 4.1 4.1.1 4.1.2 4.1.3 4.1.4 4.1.4.1 4.1.4.2 4.1.4.3 4.1.4.4 4.1.4.5 4.1.4.6 4.1.4.7 4.1.4.8 4.2 4.2.1 4.2.1.1 4.2.1.2 4.2.2 4.2.2.1 4.2.2.2 4.2.2.3 4.3 4.4

Photon spectrometers Detectors Scintillation detectors Semiconductor detectors The pulse amplitude spectrum Relevant characteristics of detectors Maximum measurable count rate Energy resolution Full energy peak counting efficiency Signal-to-Compton ratio Relationship between photon energy and pulse height Energy limits of the measurable photon spectrum Detector geometries available Miscellaneous aspects and summary Photon counting electronics Linear amplifiers Preamplifiers Spectroscopy amplifiers Pulse height measurement Single channel analysers Multichannel analysers Miscellaneous options The spectrometers used for the present work Preparation of semiconductor photon spectrometers for analysis

93 95 97 101 109 120 120 122 126 129 130 130 131 132 138 139 139 140 143 145 146 155 156 158

5

Properties and yields of radionuclides produced through ρ hotonuclear reactions General remarks Experimental conditions Selection of the elements Irradiation conditions Measurement conditions and spectra processing Data tables

161 161 162 162 162 163 165

5.1 5.2 5.2.1 5.2.2 5.2.3 5.3

VII

5.3.1 5.3.2 5.3.3 5.3.4 5.3.5 5.3.6

The photonuclear reactions of the elements Low energy photon spectra Low energy (E < 90 keV) γ-rays High energy (E < 90 keV) γ-rays Competing reactions in photon activation analysis Sensitivities in photon activation analysis

165 194 213 218 300 305

6 6.1 6.1.1 6.1.2 6.1.2.1 6.1.2.2 6.1.2.3 6.1.2.4 6.1.2.5 6.1.2.6 6.1.3 6.1.3.1 6.1.3.2 6.1.3.3 6.1.3.4 6.1.4 6.1.4.1 6.1.4.2 6.1.4.3 6.1.4.4 6.1.5 6.1.5.1 6.1.5.2 6.1.5.3 6.1.5.4 6.1.6 6.1.6.1 6.1.6.2 6.1.6.3 6.1.6.4 6.2 6.2.1 6.2.2 6.2.3

Analytical application Light element analysis The analysis of light elements other than C, Ν, Ο and F The analysis of carbon, nitrogen, oxygen and fluorine Irradiation Surface treatment Activity counting Reference materials Interferences Sensitivity Carbon Non-destructive analysis Radiochemical analysis Reference materials; error sources Sensitivity Nitrogen Non-destructive analysis Radiochemical analysis Reference materials; error sources Sensitivity Oxygen Non-destructive analysis Radiochemical analysis Reference materials; error sources Sensitivity Fluorine Non-destructive analysis Radiochemical analysis Reference materials; error sources Sensitivity Single and multielement analysis (Z greater than 10) Introduction Reference materials and radiation monitoring General analytical procedure

311 313 315 317 317 321 325 329 329 333 336 336 337 351 356 358 358 359 361 370 371 372 373 382 386 388 388 390 396 399 401 401 403 410

VIII

6.2.3.1 6.2.3.2 6.2.3.3 6.2.3.4 6.2.4 6.2.4.1 6.2.4.2 6.2.4.3 6.2.4.4 6.2.4.5 6.2.4.6 6.2.4.7 6.2.4.8

Sample preparation, transfer and irradiation Preparation for counting and photon spectroscopy Data handling Error sources Applications Systematic compilations Environmental analysis Analysis of biological material Geochemical analysis Analysis of raw materials and industrial products Analysis of archaeological material and forensic analysis Comparison studies; analysis of reference materials Systematic single element study

410 413 415 419 443 443 454 480 504 516 529 540 568

Bibliography

615

Subject index

697

Preface

This book is written to give, in a concentrated form, an overview of the application of photonuclear reactions to activation analysis. It is intended to acompany the analyst's work in the photon activation analysis laboratory as a practical usable reference. Emphasis is placed upon analytical qualitative and quantitative data which are based upon experimentally obtained results. Therefore, both a source of general information on photon activation analysis and a laboratory manual are combined in this book. The results of the authors' laboratory work and a large amount of literature data are evaluated and presented as completely as possible by the authors. Special knowledge of photonuclear physics is not required; only a very elementary theoretical introduction is given. More detailed information on the physical and mathematical theory should be sought in the special literature which is cited in the relevant chapters. The first chapter opens with a short introduction into the subject and a short survey of the history of photon activation analysis. Then the different types of nuclear reactions used for activation analysis are discussed. Finally, the quantitative relation between activating radiation and the radioactivity induced in the irradiated material is evaluated. The second chapter deals with the different types of photonuclear reactions. It commences with a historical summary of photonuclear research. The different photonuclear reaction mechanisms are then discussed, including the general nuclear properties of the reaction product nuclides. In the third chapter, again after a short paragraph on the historical development, the principles of the photon sources which are used for activation analysis purpose are explained. Isotope sources, betatron, microtron and linear accelerator are included. Their properties are compared and discussed. Irradiation facilities and apparatus for sample handling are covered. The fourth chapter is concerned with the radiation measurement systems used for photon activation analysis, especially high resolution photon spectrometers. After a few historical data, the different photon detectors and electronic devices for radiation counting are discussed. The fifth chapter contains an extended compilation of the photonuclear yield data of analytical importance. All elements of the Periodic Table with few exceptions are

2

included. Reaction types and activity yields are based exclusively upon experiment. This chapter is intended to be used during practical analytical work, e.g. for identification of radionuclides by their photon emission energies, quantitative evaluation of interference reactions, estimation of analytical sensitivities etc.. Chapter six (section 6.1) deals with photon activation analysis of the light elements (C, N, O, F). This is a special application which entails problems which are different from those occurring during photon activation analysis of the heavier (Z greater than 10) elements. The different chemical separation procedures will be outlined. In section 6.2 the analysis of the heavier elements is discussed. Cases of single- and multielement determinations are described. Summaries of fundamental photon activation analysis work presented in the literature are given as typical examples for the large variety of different problems. These include analyses of various material classes (organic matter, ores, rocks, water etc.) for different purposes (purity assessment, prospection, environmental analysis etc.). The cited literature is as complete as possible to the authors and comprises (hopefully!) the most relevant publications on photon activation analysis. The authors wish to express their appreciation to all who helped to realise this work in any way, be it by advice and critical and helpful discussion, or by practical cooperation during our laboratory work, data collection and evaluation, writing and reviewing. We are especially indebted to Professor R. Neider, who, as the head of our group, encouraged us to complete this work and had significant influence upon its contents by frequent advice and critical discussion. This work would not have been realised without the help of: U. Coester, Th. Dudzus, Dr. H.-U. Fusban, Dr. Ρ Jost, Μ. Kühl, D. Lapuse, H. Pittelkow, Dr. Ρ Reimers, K. Saracoglu, Β. Ε Schmitt, I. Segebade, R. Wiese, B. Wilke and, in particular, Mrs. Mary Thomany and the ladies of the department 7.113, Mrs. Gabriel, Mrs. Glöckner and Mrs. Blamberg. Fianally, the assistance of C. Retzlaffin the literature research is gratefully acknowledged.

Thanks to you all!

Berlin, Washington D.C., May 1987

C. Segebade H.-P Weise G. J. Lutz

3

1

Activation analysis - the general principle

1.1

Introduction and history of photon activation analysis

Activation of

analysis has now been established as a versatile and useful method

elemental

determination

for

more

than

forty

years.

Activation

analysis

is

the only elemental analytical method which is based upon reaction in the nucleus of the atom.

By activating

radiation - particles or photons - target

ele-

ment nuclei are transferred to an excited state which can decay by quasi-prompt particle or gamma emission into product nuclei which in most cases are radioactive. Both the prompt radiation and the radiation emitted by the radioactive product nuclide can be measured with appropriate radiation detectors. From the energy and the count rate of the detected particles,

qualitative and quantitative data

of the target material composition can be derived.

Thus it is clear that by ac-

tivation analysis methods only elements - not chemical species - can be d e t e r mined

directly.

detectors),

With help of

simultaneous

chemical separation of

suitable radiation

spectrometers

(high

resolution

multielement determinations can be performed

the components.

As will be shown later on,

without

extremely

high sensitivities can be achieved in many cases, and there are yet other advatages

of activation

analysis which

will be explained

in the

relevant

chap-

ters. However, activation analysis methods compete with other modern analytical techniques.

Compared with these other methods activation analysis has the disad-

vantage of relatively large requirements concerning both instrumental equipment and

personnel

source

which

qualification. provides

at a suitable e n e r g y

These

consist

sufficiently high range

in

flux

the

availability

densities of

of

a

radiation

activating

particles

(particle accelerator or nuclear reactor) and

ap-

propriate instrumentation for nuclear radiation measurement as mentioned above. Moreover,

the handling of radioactive matter unavoidibly requires special labo-

ratory installations and equipment and also special working procedures to meet the legal

radiation

protection

requirements.

Finally,

the laboratory

personnel

have to be specially trained and experienced in the handling of radioactive material, in

which generally means a longer training period than commonly necessary

conventional

analytical

problem in photon activation

laboratories. analysis;

Additionally,

there

is

a

special

very often chemical analysts have only

limited access to suitable radiation sources. This phenomenon becomes obvious

4

and explainable along with a closer view of the historical development of photon activation

analysis.

This

problem

will be discussed

in more detail

later.

These drawbacks are some of the reasons why activation analysis is not yet as broadly applied in analytical science as other techniques,

although it o f f e r s a

good list of convincing advantages to the analyst. Even supplied with s u f f i c ient equipment and well-trained laboratory personnel people do not necessarily become active in activation analysis, because the special advantages of the method are not yet commonly known and frequently they tend to keep solving their analytical problems along conventional lines,

even though they could be solved

more efficiently with the help of activation analysis.

In the following short summary of the historical development emphasis will be placed upon photon activation analysis.

Excellent historical reviews on the hi-

story of activation analysis in general can be found in the basic literature on neutron activation analysis; see e . g .

Ref.®^.

The first photonuclear activation for analysis purpose was performed with help of radionuclides as an activating ported

first in the beginning

beryllium

determinations

by

radiation source.

of the 1 9 5 0 ' s * ' 2 , photodisintegration

These applications are

although apparently the were

performed

in

refirst

the

late

1930's^, which would make the beginning of photon activation analysis contemporary with the fundamental works on neutron activation analysis by v . Hevesy and L e v y 4 and charged particle activation analysis by Seaborg and L i v i n g o o d 5 . However,

there is no contemporary information available about this pioneering work

in the Soviet Union.

Although

the analytical

restricted

to

the

sensitivity

analysis

of

is relatively

deuterium,

poor and

beryllium,

and a few nuclei which have low-lying isomeric states, ing

radiation

plained.

sources are

Later on,

the applicability

several

fissile

is

nuclides,

radionuclides as excit-

still in use nowadays as will be subsequently

ex-

small static accelerators have also been used f o r determin-

ations of the mentioned elements. A f t e r the advent of high energy cyclic electron accelerators

(betatron,

microtron,

linac) the high energy

bremsstrahlung

produced by these machines has been used f o r photon activation analysis. As a result,

the list of determinable elements increased dramatically and now,

with

a few exceptions, has covered the entire Periodic Table. The analytical potential of

these

radiation

sources

was

first

recognised

at the

beginning

of

the

1950's. Basüe et al.® proposed to analyse some of the light elements ( C , N, O ) using photonuclear reactions induced by bremsstrahlung from a betatron.

5 In the case of the analysis of these elements, in general, a chemical separation from the sample matrix must be performed after bremsstrahlung exposure. A great deal of fundamental work was devoted to this problem during the 1960's. These publications are discussed in more detail in chapter 6 . 1 . Along with the maturity of improved gamma spectroscopy equipment the extension of the method to heavier elements was straightforeward. It is not easy to find out who did the pioneer work on instrumental photon activation analysis of elements with Ζ greater than 10; as will be shown in chapter 6 . 2 , there were several analytical groups in the early 1960's who did - more or less independently - the first instrumental photon activation analysis work on these elements. Currently, in

finalising

this short historical review, photon activation analy-

sis has been established as a complementary method to other instrumental analytical techniques with a good list of special features which can not be offered by other methods, and, of course, with some unavoidable drawbacks. More detailed information on the historical development are given at the beginning of each of the following chapters.

6

1.2

Types of nuclear reactions used for activation analaysis

Generally

expressed,

as metioned

above,

radiation of a suitable energy

can

transform target nuclei into product nuclides. This process is accompanied by prompt emission of particles or photons. It can be expressed such:

T + a

p+ b

or, more concisely,

T(a,b)P

where Τ is the nucleus to be activated ( t a r g e t ) , ticle,

b the promptly

emitted

(1)

a the incident radiation par-

particle and Ρ the activation

product

nuclide.

The type of the nuclear reaction depends upon the target nucleus and the nature and energy of the incident radiation. Both a and b can be nucleons or photons. In the most cases the activation product Ρ is a radionuclide decaying by β" or 6 + - emission or by electron capture. Often the product nuclides emit gamma- and and X-rays which are characteristic for each nuclide. Thus it is of advantage to use photon spectroscopy for product nuclide identification and radioactivity measurement. Moreover, because of the low absorption of photon (gamma and X ) radiation,

one generally does not have to take into account significant matrix

absorption during counting of radioactivity. In the following,

the different

types of analytically

usable nuclear

reactions

are delineated. 1.2.1

Neutron activation

Among the various nuclear activation methods, the analysis by activation with neutrons was developed first (Hevesy and Levy"*) and still nowadays is the most frequently

applied.

In general,

thermal neutrons

(ca.

from nuclear reactors have been utilised for activation.

0.025 eV = 2200

ras"1)

Thermal neutron flux

densities of some 10*"* to some 10^^ cm~^s~* are common in modern nuclear research reactors.

7 Using t h e s e n e u t r o n s as activating particles, a n e u t r o n c a p t u r e reaction is the most probable one,

e.g.:

23

Neutron for

trace

activation element

N a ( n , γ)

24

Na

as performed with reactor n e u t r o n s is particularly analysis

because

of the high intrinsic sensitivity

useful of

this

method for the determination of many elements; detection limits of some 10-® grams and even lower a r e not u n u s u a l . However, d i f f e r e n c e s in t h e sensitivities among t h e elements a r e l a r g e ; they cover many o r d e r s of magnitude. In some s p e cial cases this might t u r n to a d v a n t a g e , b e analysed sections

e . g . , if the matrix of the sample to

consists of elements with small thermal neutron activation

while

the

trace

elements

to be determined

have

very

cross

large

ones.

However, in many cases analyses a r e severely hampered by excessive matrix activities

after

thermal

neutron

activation,

so that

a chemical

separation

step

must be included into the analytical p r o c e d u r e . n i l

Neutrons from radionuclide s o u r c e s , e . g .

ηtrt

Am/Be o r

Cf have also been used

f r e q u e n t l y f o r activation. The p a r t i c u l a r a d v a n t a g e of isotope neutron sources is t h e absolute source intensity stability of t h e nuclide. Furthermore, they do not r e q u i r e excessive space and they a r e relatively inexpensive; both the financial e f f o r t and

the space r e q u i r e d

for a r e a d y - t o - u s e irradiation

facility

is largely governed by i t s radiation shielding. The neutron flux density of an isotopic source is lower than

available in thermal neutron irradiation

posit-

ions of nuclear r e a c t o r s by many o r d e r s of magnitude. T h e r e f o r e , the application is r e s t r i c t e d . Isotope sources a r e f r e q u e n t l y used for on-stream analyses within i n d u s t r i a l production p r o c e s s e s , if rapid determinations of major or minor components a r e required;

trace element analyses a r e possible only in a few exceptionally

ad-

vantageous cases. A similar field of application is found f o r d , T - n e u t r o n g e n e r a t o r s . By nuclear reaction of d e u t e r o n s with t r i t o n s monoenergetic n e u t r o n s of about 14 MeV a r e p r o d u c e d . In a neutron g e n e r a t o r d e u t e r o n s a r e p r o d u c e d , accelerated by high voltage of typically 150 kV and then absorbed by a metal t a r g e t which contains up to some 1 0 ^ Bq of tritium. The 14 MeV-neutrons t h u s produced induce d i f f e r e n t reactions in an irradiated target element; the most probable reactions a r e of t h e ( n , 2 n ) , ( n , p ) , or ( η , α ) t y p e . The activation cross sections of t h e s e

8

reactions are smaller by one to three orders of magnitude than those of

(n,y)

reactions induced by thermal neutrons. Moreover, the flux densities achievable ο with conventional neutron generators are comparatively low, typically some 10 Therefore, as in the case πof isotope sources, trace component analyses are possible in only v e r y few cases . More recently,

high flux 14 MeV irradiation tubes have been developed

which

provide neutron flux densities up to ΙΟ·*·* cm'^s"^, and thus the area of application

of

fast

neutron

activation

analysis

can

be

extended

to

more

trace

determinations®·

A typical application of 14 MeV neutron activation analysis is the oxygen

de-

termination via the reaction

160(n,

p)

16N

In this exceptional case detection limits of some tens of micrograms per gram are possible (Neider et al. 1.2.2

Activation with charged particles

Charged

particles

produced

Graaff accelerators,

by

ion accelerators,

e.g.

cyclotrons

or van

de

can be used for activation. The major difference is due to

the small range of charged particles in matter compared to uncharged particles like neutrons or photons. Therefore, in using charged particles for activation, one must be aware of a strongly inhomogeneous spatial activity distribution in the irradiated sample. This can be an advantage if a surface analysis is requir e d . One can easily predetermine the thickness of the activated layer by selecting a proper particle e n e r g y . Thus, a surface layer with well-known thickness is

exposed

to

the

incident

radiation

rather

than

the

bulk

of

the

sample.

Shortly after the discovery of the phenomenon of induced radioactivity a variety of machines were developed to accelerate particles capable of inducing dioactivity in matter.

ra-

Among them, only van de Graaff accelerators and small

cyclotrons

have found widespread use in charged particle activation analysis.

Currently,

compact cyclotrons are available which supply light ion beams with

energies of some tens of MeV at beam currents up to a hundred microamperes. Particles

with

much

higher

energies

are

not

useful

for

activation

analysis

since high energies lead to possible interference by unwanted reactions in the

9

sample (see cyclotrons

Ch.2). can

Moreover,

also

produce

equipped neutrons

with light at

element

energies

converter

convenient

for

targets, activation

analysis; typical achievable flux densities are several 10*" c m ' V ^ . Finally, in

alpha-emitting

very

special

radionuclides,

cases

( T u r k e v i c h et a l . 1 2 ,

can

be

e.g.

used

Cm, should be mentioned,

as an activating

alpha

radiation

3 He,

ec j32-4'2 >

and

alpha

particles14-3*.

One can also exploit

tion analysis.

is

the

emission

Heavy

the prompt

ions

have

also

deuterons,

been

propos-

radiation in charged particle activa-

Also the measurement of the X-ray fluorescence excited by char-

ged particles should be mentioned, tivation

source

Wakita 1 3 ).

The particles which are commonly used for activation are: protons, tritons,

which

process. possibility and

the

although this is not based on a nuclear ac-

A special advantage of

simultaneous

promptly

of

charged

measurement

emitted

gamma

of

particle activation the

radiation

analysis

particle-induced utilising

an

X-ray

appropriate

detector system. Other particular advantages compared with other nuclear methods are:

- The large variety of particles available for activation -

the quasi-free choice within a large range to favour desired nuclear

reac-

tions -

the

high

intrinsic

sensitivity,

especially

for

light

element

analysis;

de-

tection limits in the subnanogram level are not uncommon. 1.2.3

Photon activation

According to e q . l in paragraph 1.2, a photonuclear reaction is described

by:

T(-/,b)P

where b may stand for a large variety of particles, the incident (γ,3η),

irradiation. prised,

photon

(γ,ρ),

energy.

Usually

depending primarily upon

b is equal to gamma or n,

but

(γ,2η),

( γ , η ρ ) and other reactions can be induced as well during photon

The

as already

first

applications

mentioned,

of

activation

analysis

with

photons

the determination of the light elements

com-

(deuter-

ium, beryllium, carbon, nitrogen, oxygen and f l u o r i n e ) . The nuclear properties

10 of these elements favour the exploitation determination,

activation analysis. experiments.

of photonuclear

reactions

for

their

as their nuclear properties are unfavorable for thermal neutron Isotope sources were used for the first photon activation

Consequently,

the

analytical application

was then

restricted

to

two groups of elements: a) Those with neutron binding energies less than the gamma energies emitted by practically

usable

(due

nuclide sources like

to their

2 4 Na,

60Co,

half-lives 124Sb

and available activities)

radio-

etc.

The two only stable nuclides which can be analysed under these conditions are π q ι ο ο Η and

Be » ' . In this book only those applications are discussed in detail

which include the use of delayed activity counting. Therefore, tegration

analysis

of deuterium,

beryllium

the photodisin-

and fissile elements using

prompt

radiation counting is only mentioned marginally if r e l e v a n t . b ) Nuclides which have isomeric states with sufficiently long half-lives can be excited by ( γ , γ ' ) - r e a c t i o n s induced by gamma-rays from the mentioned radionuclides, e . g .

77Se,

107Ag,

115In.

With the advent of high energy

accelerators,

photon activation

analysis

was

first extended to the determination of carbon, nitrogen, oxygen, and, somewhat later,

fluorine.

exclusively,

The reaction products of these elements decay by ß + -emission

hence

only

tivity measurement.

unspecific

Consequently,

annihilation

radiation

is available

for

ac-

in almost all cases a radiochemical separa-

tion of the activity to be counted from the sample matrix after bremsstrahlung exposure is required.

Usually large

used for activity

measurement.

with

intrinsic

the

lowest

scintillation

crystal

detectors

they

have

been

been

The four mentioned elements are among those

sensitivity

for

photon

activation

analysis;

photonuclear reactions have comparatively unfavorable nuclear data. less,

have

determined

frequently

with help of photon

their

Nevertheactivation,

since this method is relatively free from problems of apparatus blanks and surface

contaminations,

whilst

conventional chemical analysis methods

suffer from these i n t e r f e r e n c e s .

Therefore,

frequently

in spite of the comparatively small

c r o s s sections the detection limits of these elements in photon activation

ana-

lysis are extremely low; nanogram amounts are easily determinable in some cases (see

Ch.6.1).

In considering the determination of the heavier elements,

there is u number of

elements heavier than neon which can be analysed more advantageously by photon

11

activation than e . g .

by neutron activation.

These will be discussed in detail

in C h . 6 . 2 . While the photon activation p r o d u c t s of the light elements - as mentioned above - give rise to annihilation radiation only,

the photonuclear reaction

of the heavier elements - as in neutron activation - usually emit

products

characteri-

stic gamma and X - r a y s . When determining these elements, one generally s t r i v e s f o r an analytical p r o c e d u r e without chemical separation. Especially in the case of f u l l - s c a l e analysis of a multi-component sample one has to be concerned with complex gamma-or X-ray s p e c t r a a f t e r activation. T h u s it is necessary in the most cases to perform activity measurement with the aid of high-resolution

se-

miconductor photon s p e c t r o m e t e r s . Data processing by computer systems including microprocessor-equipped

multi-

channel pulse-height a n a l y s e r s with many t h o u s a n d s of channels available has become more and more sophisticated; q u a s i - f u l l automatic analysing devices a r e not unusual nowadays (see C h . 4 ) . Generally, as

large

the d i f f e r e n c e s of sensitivities among the elements a r e by f a r not as in

neutron

activation

analysis;

typically

the

detection

limits

-

assuming a purely i n s t r u m e n t a l analysis - lie between 0.01 and 1 microgram. The practical sensitivity is often limited by high matrix radiation b a c k g r o u n d . Photon activation analysis, as well as o t h e r activation analysis methods,

gene-

rally is quantified by comparison of the activities in the sample with those in a r e f e r e n c e material of known elemental composition which was irradiated simultaneously.

This is necessary

particularly

in photon activation analysis

since

some of the machine parameters of the accelerator and also some of the nuclear data of t h e reactions a r e , respectively, either unknown o r not precisely d e t e r minable. Moreover, some machine parameters of t h e photon source cannot be considered constant t h r o u g h o u t t h e e x p o s u r e period. By the use of r e f e r e n c e materials which a r e simultaneously i r r a d i a t e d with the sample u n d e r identical conditions

these

parameters

are

implicitly

accounted

for.

Frequently

certified

multielement r e f e r e n c e materials a r e used whose matrix compositions are similar to those of the samples to be a n a l y s e d . T h e r e a r e many problems associated with r e f e r e n c e materials and their p r o p e r use; these a r e discussed in C h . 6 . Finally,

the

availability

various

of high

fields resolution

of

application

are

dicussed.

With

the

spectrometers instrumental multielement

general photon

activation analysis has been involved in routine analysis work with a broad

12 application s p e c t r u m . In this book the following applications a r e r e p o r t e d and discussed: - Geo- and eosmochemistry - Oceanography - Environmental science - I n d u s t r i a l raw- and end product analysis - High p u r i t y material analysis - Organic material analysis (biological and medical material) - Forensic analysis - Analysis of objects of a r t and archaeology - Certification analysis of candidate r e f e r e n c e materials Among this

these

book,

applications,

radiochemistry

instrumental in photon

analyses a r e discussed

activation

in detail;

analysis is r e s t r i c t e d

to

in the

determination of t h e light elements and a few selected examples of analysis of heavier elements. For more general information about photon activation analysis the r e a d e r might r e f e r to U e f ' s . 1 6 _ 2 5 · 3 0 · 31> 43-86,683 # I t i s a l s o r e C ommendable to s t u d y the contributions about photon activation analysis in the proceedings of several analytical - radioanalytical in particular - c o n f e r e n c e s ; see R e f ' s . 62-68,70, 74,87-94

13

1.3

The

Calculation of the induced activity

quantitative

analysis

utilising

any

kind

of nuclear activation

is almost

invariably based upon comparison of the radioactivity induced in the analytical sample

and

Therefore,

the

reference

material,

as

noted

in

the

preceding

paragraph.

the actual activity induced in the element to be analysed does not

have to be determined explicitly for analytical evaluation.

However, for a va-

riety of reasons, it is of advantage to have knowledge about the activity of an element

after

activation,

e.g.

for comparison

of sensitivities,

integral matrix activities to be expected e t c . . of this book

Therefore,

( C h . 5 ) relative activity yields are presented.

calculation

of

in the data section These values are

derived from the following mathematical considerations. During exposure to any kind of activating radition both stable and radioactive nuclei are formed. In the following, consideration,

since stable product

only radioactive products are taken into nuclei generally are of no analytical rele-

vance. The variation of the number of product nuclei as a function of time may be expressed thus:

dN _ = N+-x-N(t)

(1.1)

N(t) = number of radioactive nuclei at the time t N+ = production rate of the product nuclei λ = decay constant of the reaction product In

this

linear

differential

equation

the balance of production

and decay

is

described. The solution of this equation under the initial condition

N(t = 0) = 0

yields: N+ N(t) = — · ( ! - e " A

t)

(1.2)

14

At t h e e n d of t h e i r r a d i a t i o n period T j t h e total n u m b e r of p r o d u c t nuclei i s :

N+ N(T,) = — · (1

T

λ

')

(1.3)

T j = i r r a d i a t i o n period A f t e r t h e i r r a d i a t i o n t h e p r o d u c t i o n r a t e becomes zero a n d e q . 1 . 1 is t h e n modified t h u s :

dN "dt~

= -ÄN(t)

(1.4)

T h e solution of e q . 1.4 u n d e r t h e initial condition given by e q . 1.3 i s :

Ν = Ν (Τ;) · e -Α-(ι-Τ,)

(1.5)

T h e n u m b e r of p r o d u c t nuclei a f t e r t h e d e c a y period Tjj m e a s u r e d from t h e end of the irradiation is:

N ( T D ) = N ( T , ) - e -ilT D

(1.6)

From e q . 1.6 t h e a c t i v i t y of t h e p r o d u c t follows:

A =

and,

dN "dt7

= Λ · Ν (T D )

i n c l u d i n g t h e e x p r e s s i o n f o r t h e formation of t h e p r o d u c t d u r i n g

tion ( e q .

(1.7)

activa-

1.3):

(1.8)

15 Calculation of the production rate (N + ) The number of product nuclei per time unit in a target sample can be expressed as: d N + = nT · VT · σ(Ε) • (pE(E)dE

(1.9)

n j = number of target nuclei of the isotope under consideration p e r target volume Vrj, = homogeneously irradiated target volume σ(Ε) = cross section of the activation reaction as a function of the incident particle energy (see Fig. 1.1) (t>g(E)dE = flux density of the incident particles between the e n e r gies Ε and Ε + dE (see F i g . 1 . 1 )

\

\

\ >ai 10,-1 I Τ ΙΛ >7 * 'e C C ~ ζ1 ufuf

\

\

j>E(/T,£0)

\χ

x

—

1 0

U j Uj"

10-3

J'X

\

\ \

\ \

\ — - Λ ν— \ 1

30

fth 10 £ g r 20 Electron Energy in MeV —

Em

Fig.1.1: Bremsstrahlung spectrum and photonuclear cross section $E(E,EQ)

= differential bremsstrahlung flux density;

f(E,Eg)

= normal-

ised bremsstrahlung spectrum; σ(Ε) = photonuclear reaction cross section; EQ = electron energy; Ε th bremsstrahlung energy (= E.)

threshold energy; Ε max

maximum

16

Using more convenient physical quantities, V,p · N T may be replaced by:

V

T

n

T

=

ρ·L·h·V

=

m-L-h

(1.10)

p = density of the element under consideration in the sample m = mass of the element L = A v o g a d r o ' s number (=6.023 · 10 23 m o l _ 1 ) h = abundance of the target isotope A r = relative atomic mass of the target isotope Integrating eq. 1.9 one yields the following expression for the production rate of the active nuclei in the target:

m ' L ' h Emax N+ = — j σ ( Ε ) ·

+ -emission which l e a d s t o e x c i t e d s t a t e s of t h e d e c a y p r o d u c t a c c o m p a n i e d with s u b s e q u e n t g a m m a - r a y emission o r without gamma emission d i rectly to the ground

s t a t e ( a s in t h e c a s e of ^ C ,

^F).

Neutron-

d e f i c i e n t r a d i o n u c l i d e s with medium and h i g h atomic n u m b e r d e c a y t h r o u g h two c o m p e t i n g modes, namely l£ + -emission a n d e l e c t r o n c a p t u r e ( E C ) . E l e c t r o n c a p t u r e in g e n e r a l also l e a v e s t h e d e c a y p r o d u c t in an e x c i t e d s t a t e which r e t u r n s the ground state through nucleus

captures

gamma-ray emission.

electron

I n s t e a d of p o s i t r o n emission t h e

an o r b i t a l e l e c t r o n - p r e d o m i n a n t l y a K - e l e c t r o n - t h u s

v i n g an e l e c t r o n hole in t h e K - s h e l l . an

from a h i g h e r

to lea-

When t h i s hole i s s u b s e q u e n t l y filled b y

shell c h a r a c t e r i s t i c

X-radiation

is p r o d u c e d

or

an

A u g e r - e l e c t r o n is e m i t t e d . For h e a v y n u c l e i X - r a y emission i s f a v o u r e d . T h e Xr a y e n e r g y i s p r o p o r t i o n a l to t h e s q u a r e of t h e atomic n u m b e r .

In t h e c a s e of

h e a v y e l e m e n t s X - r a y s p e c t r o s c o p y can be u s e d a s an a l t e r n a t i v e to c o n v e n t i o n a l

52 γ-ray spectroscopy because the X - r a y photons have a conveniently high energy (up to about 80 keV) and the emission probability is sufficiently high C h . 6 . 2 and

(see

Ref's.154"161).

In the case of a target element having several stable isotopes this series of isotopes may be interrupted by one or more ^'-emitting radionuclides. Then also ^'-emitting radionuclides can be produced from this element through photoneutron reactions and analysed by conventional gamma-ray spectroscopy. The most important production mode of ß~-active radionuclides in photon activation analysis,

however, is the (γ,ρ)-reaction which reduces the number of protons in

the nucleus so that a neutron-rich radionuclide is generated. In the most cases these radionuclides can be analysed by gamma-ray spectroscopy. There are only a few unfavourable cases in which the reaction product does not emit nuclide specific gamma-rays. In general the nucleus originating from a photonuclear reaction is not produced in its ground state but in an excited state. This excitation energy of the produced nucleus is released by gamma-ray emission. Since the lifetime of the excited states are generally very short this so called prompt gamma-radiation is emitted almost immediately after the formation of the product nucleus thus leaving the nucleus in its ground state. If the ground state of the product nucleus is unstable a radionuclide was produced which is transformed into a decay product. Like the photonuclear reaction the radioactive decay of the product nucleus leads to excited states of the decay product. It is the deexcitation gamma-radiation of the decay product which is normally analys e d . In practice, the prompt gamma-radiation from the photoreaction product is not used for analytical purpose because this method would require gamma-ray spectroscopy

during

irradiation

bremsstrahlung background.

which

is

exceedingly

difficult

due

to

the

However, there are remarkable exceptions. If the

reaction product has an isomeric state with sufficiently long half-life the analysis of the gamma-radiation from the reaction product can be performed in the laboratory reaction

after

irradiation.

Particularly

product

is a stable

nuclide

simple

is

the

case

with an isomeric state.

in

which

the

With a certain

probability, by the reaction

1 3 6 Ba(y,

the product

n)135mBa

is formed in the isomeric excited state with 28 h half-life.

The

268 kev gamma-radiation from the transition to the ground state of ^ ^ B a can be conveniently measured off-line.

53 In other c a s e s the reaction product having an isomeric state i s unstable. isomere

originating

from

the

photonuclear

reaction

can

transite

to its

The (un-

s t a b l e ) ground s t a t e , accompanied by gamma emission and then the ground state s u b s e q u e n t l y is transformed into an excited state of the decay product,

follow-

ed by gamma-ray emission.

134

Ba(y, n)133mBa

133mBa

133

_!L_

Ba

133

133

B a

Cs

=

2 7 6

fceV

E y = 356 keV

Even longer d e c a y - c h a i n s might o c c u r . Sometimes product:

the

isomeric

Then

only

reaction

the

product

gamma radiation

directly

transforms

into

from

the deexcitation

Ey

475keV

the

decay

of the

decay

product is o b s e r v e d .

103

Rh(y, n)102mRh

io2mRh _ ! £ _

IO2Ru

=

Isomeric s t a t e s exist only in medium and heavy nuclides. 2.5.3 If

a

Fissile nuclei fissile

nuclide

is excited

fission of the nuclei may o c c u r .

by

high

energy

photons

deexcitation

through

Instead of a single reaction product a broad

spectrum of radionuclide ranging from low atomic number up to heavy elements i s produced in close analogy to fission induced by thermal n e u t r o n s . Most of these products are l i " - e m i t t e r s .

Due to the vast variety of radioactive fission

pro-

ducts the gamma-ray spectrum from irradiated uranium, e . g . , is extremely complex.

Therefore,

in general the photofission

for the analysis of fissile elements.

Moreover,

reaction is only of limited value the complex gamma-ray

spectra

of photofission products might appear as a serious i n t e r f e r e n c e source if h i g h er

concentrations

6.2).

of

fissile

material

are

present

in

the analsed

sample

(see

54 Another method for measuring the overall concentration of fissile elements in a sample is the detection of neutrons which are also emitted as a consequence of photofission. non-fissile

In contrast

elements

this

to gamma-ray spectroscopy method is

not

used for the analysis of

nuclide-specific

because

the

fission-

neutrons do not supply any information about their origin. Another drawback is due to the fact that the neutrons must be detected during irradiation (in-beam analysis) which is difficult on account of background

problems (see

above).

Another method for discriminating between different fissile nuclides present in the sample makes use of the different photoneutron thresholds.

Here the elec-

tron energy of the accelerator and hence the maximum photon energy is varied. When the electron energy passes the threshold of a fissile nuclide the neutrons yield r i s e s . (e.g.

Since the photoneutron

232Th,

235U,

discrimination

238U,

239Pu)

between different

different context -

yield curves of different

fissile

nuclides

are markedly different near threshold a rough nuclides becomes p o s s i b l e * " 2 ;

see also - in a

Ref.181.

Furtherly recommended literature about high energy photon reactions: Ref-870.163-176.

2.5.4

Neutron-induced reactions

In practical photon activation analysis work one sometimes encounters radionuclides which can only be attributed to neutron-induced reactions.

The

neutron

source responsible for these reactions is the bremsstrahlung converter of the electron

accelerator.

In the heavy metal of the converter

photoneutrons

are

produced by the bremsstrahlung thus yielding a considerable neutron flux density at the irradiation position of the sample. The shape of the neutron spectrum depends on the material in the vicinity of the bremsstrahlung c o n v e r t e r .

Be-

sides the primary photoneutrons a large low energy component is produced by moderation of the primary neutrons in the surrounding material. Therefore,

two

types of neutron-induced reaction may occur in the sample. Low energy neutrons may be captured by ( n , y ) - r e a c t i o n s and neutrons with sufficiently high energy may induce threshold reactions e . g . ( n , p ) or ( η , α ) p r o c e s s e s . By ions,

in contrast

to the complementary

(Y,n)-reactions,

(n,y)-react-

neutron-rich

ß~-emit-

t e r s are produced. This is the neutron reaction type most frequently observed in photon activation analysis. actions reactions

do not

produce

Al(n,p)

found useful.

In the case of aluminium

analytically

Mg and

suitable

(γ,η)-

radionuclides.

In

and

(y,p)-re-

this case

the

A l ( n , a ) 2 4 N a induced by photoneutrons have been

55

Normally reactions with photoneutrons are not analytically exploited because of several 6.2.

difficulties

Moreover,

However,

analysis.

E.g.,

with

This

is explained

further

in

in a few cases photoneutrons have been used for activation

in the authors' laboratory an irradiation position was instal-

at the accelerator

fields

standardisation.

frequently the achievable neutron flux is insufficient for trace

analysis. led

concerning

variable

which allows the activation of

cadmium

ratios and

samples in

which are practically

photoneutron

f r e e from

high

e n e r g y photon contamination (see C h . 3 ) . The achievable neutron flux density is comparatively

poor

(several

trace determinations can be performed

ι

; nevertheless,

in advantageous cases

nn

. For example, routine analyses of se-

veral elements in air dust filters have been carried out successfully analysing 1 not vanadium and manganese by activation with photoneutrons ( s e e also 6 . 2 ) .

57

3

Activating radiation sources

3.1

Radionuclide sources

Radionuclide sources 1 ft "1 lysis ' · . Analyses

were of

the

first

to be applied

deuterium,

beryllium

for photon activation

and

fissile

material

have

anabeen

performed exploiting the photodisintegration process with direct observation of 1 94

the promptly emitted neutron radiation.

Strong

Sb gamma-ray sources have

been used in οalmost 1 oo all application cases (see e . g . were reported ' .

The

first

photoexcitations

achieved

with help of

practice,

mostly strong

of

isomeric

226Ra184,182Ta

states and

through

60Co

Co-sources (some 10

Ref.182),

but also others

nuclide

sources185.

radiation

were

In the laboratory

up to some 10 15 B q ) have been

a p p l i e d 1 8 5 " 1 9 2 . In a few cases others have been u s e d 1 8 5 " 1 8 8 ' 1 9 3 . In T a b . 3 - 1 the applications sources,

of

nuclide

gamma-sources

the achievable

analytical

are

summarised.

sensitivity

However,

frequently

using

s u f f e r s from

these

unsuit-

able e n e r g y of the activating radiation; normally the gamma e n e r g y of the nuclide

cannot

Therefore,

excite using

the

absorption

radionuclide

resonance

activating

scattering can only be exploited (see

level

sources,

of

the

radiation

target due

to

nuclide. Compton

Ch.2).

Higher energies can be obtained through photon radiation promptly emitted during

nuclear reaction of some elements.

In this instance,

several

ions provide useful photon energies f o r photonuclear reactions,

However,

" B ( p , y) l 2 C

Ε = 15.96 M e V

7Li(p,y)8Be

Ε =17.26 M e V

3H(p,r)4He

Ε =19.80 M e V

for different

reasons,

use for photon activation

these photon sources

(p,y)-react-

e.g.

normally are of

limited

analysis23,45>194.

Akbarow et a l . 1 9 5 used the gamma emission of reactor-produced

( b y irradiat-

ion of fluorine compounds) for photon excitation of several isomeric states. All in all, for several reasons (low achievable photon f l u x , monochromatic rad-

58

iation whose e n e r g y most probably ion level;

does not coincide with the desired

excitat-

see C h . 2 ) the use of isotopic sources for photon activation analysis

is restricted to a few advantageous cases; see also Ch.6.2.

T a b . 3-1: Isotope γ-ray sources used for photoexcitation Isotope

Half-life

Activity

60Co

5.27 a

4 · ΙΟ 1 "

(Bq)1

Isomeres produced 115m,n

6 · i o 1 2 - 7 · 10 13

115mIn

7 · io13

lllmcd

77mSe,

3 · io15

2 · io1" - 1 ·

185 79m ß r > 87m Sl>( 107m A g > lllm

Cd,

87mSr,

lllmCd, 115m In> 176m Lu

2 · IO 1 " - 4 · 10 1 "

77mSe

7 · io14

77mSe,

182 T a

115 d

5 · io13

115m,n

116mIn

56 m

not given

77m Br>

lgg

115mIn

113mIn,

189

190 79m B r > 87m Sr> 107m A g >

109m A g |, 179m Hf

186 185

109m Agi ,

io15

Ref.

187

lllmCd, 115mIn, 191m Ir> 195m pt> 197m Au

185 107m A g i

109m A g i

188

115mIn

2 4 Na

15 h

^Values were

7 · io12 transformed

integer Bequerel values.

from integer

167m Er Curie activities,

193 and

were rounded to

59 3.2

Electron accelerators

The d i s a d v a n t a g e s of the isotopic sources mentioned above can be eliminated by using b r e m s s t r a h l u n g of a c c e l e r a t o r - p r o d u c e d electrons for photoactivation. The achievable photon fluxes usually o u t r a n g e those of radionuclide sources by o r d e r s of magnitude.

Moreover,

the effective c r o s s section is significantly en-

larged since the b r e m s s t r a h l u n g e n e r g y is continuous with the electron e n e r g y . Finally, photon energies can be produced which a r e much h i g h e r than obtainable with any isotope or nuclear reaction s o u r c e . T h e r e f o r e , activating with high e n e r g y b r e m s s t r a h l u n g , photonuclear rections can be induced in the t a r g e t material, whereas - except v e r y few cases - only isomeric state excitation can be achieved by gamma-rays from isotopes (see a b o v e ) . An accelerator is a device to accelerate charged particles such as electrons, protons or heavier ions up to a kinetic e n e r g y t h r o u g h which they are enabled to induce reactions upon the electron shell or the nucleus of a t a r g e t atom. One has to distinguish primarily between electrostatic and cyclic a c c e l e r a t o r s . The term "cyclic" exclusively relates to the operation mode of the machine. In some l i t e r a t u r e one is not c o r r e c t :

finds

this term used for circular path a c c e l e r a t o r s .

This

"cyclic" in this context does not relate to the geometry of the

particle t r a j e c t o r i e s . One has also to distinguish between linear and circular machines, according to the accelerated particle path geometry. In this c h a p t e r only those machines a r e described which can be applied for the production of b r e m s s t r a h l u n g usable for photon activation. These a r e : Van de Graaff g e n e r a t o r , linear accelerator,

be-

t a t r o n and microtron. O t h e r s were used in comparably few cases and t h e r e f o r e a r e mentioned marginally if r e l e v a n t . In static accelerators electrons are accelerated by a constant high voltage potential. The maximum achievable particle e n e r g y is directly dependent upon the maximum high voltage of the individual machine. The most prominent examples a r e t h e Cockcroft-Walton g e n e r a t o r ^ ® ~ ^ 9 and t h e Van de Graaff a c c e l e r a t o r . As f a r a s it is known to the a u t h o r s the former has n e v e r been used f o r photon activation a n a l y s i s . In cyclic accelerators

electron energies

are achieved

by

multiple

application

of comparatively low voltages upon the e l e c t r o n s . The maximum achievable e n e r gy is d e p e n d e n t on various parameters. Examples of these machines a r e : linear accelerator, b e t a t r o n ,

microtron.

60 R e g a r d i n g the requirements

of photon activation analysis

( s e e C h . 2 ) it is ob-

vious that a c c e l e r a t o r s providing electron e n e r g i e s of more than say 50 MeV a r e u n n e c e s s a r y . Moreover, e x c e s s i v e l y high brems Strahlung e n e r g i e s a r e unsuitable since t h e y lead to u n d e s i r a b l e competing photonuclear reactions ( s e e According

to the

practical

experience

of

most

analysts

those

Ch.2).

machines

meet

their requirements b e s t which provide around 30 MeV electron e n e r g y at a v e r a g e beam c u r r e n t s of at least 100 microamperes ( s e e

Ch.2).

F o r more g e n e r a l information about electron a c c e l e r a t o r s used in photon a c t i v a tion analysis the r e a d e r might r e f e r to R e f s . 3.2.1

14

> 2 0 0 ~ 2 0 4 , 508 >

Van de Graaff g e n e r a t o r

T h e Van de G r a a f f belt g e n e r a t o r was f i r s t proposed in 1 9 3 1 2 " 5 . principle is shown in F i g . 3 . 1 .

The

function

An insulating belt is driven by a motor connec-

ted to one of the pulleys, at ground potential.

Near the motor-driven pulley a

row of points is located a c r o s s the width of the belt and is kept at a potential of about 30 kV ( c h a r g i n g s u p p l y ) . A corona d i s c h a r g e between t h e s e points and the moving belt ionises the atmosphere and e l e c t r i c c h a r g e is t r a n s f e r r e d to

the

belt.

electrode.

The

other

side

of the

support

is inside

the

high

voltage

Here the b e l t - b o r n e c h a r g e i s removed and t r a n s f e r r e d to the o u t e r

s u r f a c e of the high voltage e l e c t r o d e . es.

belt

The electron

source

(electron

T h u s the voltage p r o g r e s s i v e l y

gun) and the upper end of the

increas-

accelerator

t u b e a r e located inside the HV e l e c t r o d e . Normally the whole a c c e l e r a t o r assembly is located in a p r e s s u r e tank which is filled with highly p r e s s u r i s e d lating

gas,

e.g.

sulfur h e x a f l u o r i d e .

T h i s gas inhibits uncontrolled

insu-

discharge

along the h i g h - v o l t a g e b e a r i n g parts of the machine. T h e f i r s t v e r s i o n s of this machine type could produce high voltages of close to one MV and thus e l e c t r o n s of about one MeV. Modified v e r s i o n s , equipped with special i n s u l a t o r s were then quickly developed;

they could reach up to about 3

Μν206-210φ

Nowadays,

however, Van de Graaff g e n e r a t o r s which can produce up to s e v e r a l

t e n s of MeV e l e c t r o n e n e r g y a r e commercially available at comparatively moderate some

purchase

prices.

milliamperes

compact;

are

At e n e r g i e s of say not

unusual.

t h e y have been appreciated

five

These

MeV, electron beam c u r r e n t s

machines

are

relatively

for t h e i r simplicity and f l e x i b i l i t y .

fields of application a r e X - r a y d i f f r a c t o m e t r y ,

of

small and The

r e s e a r c h on the atomic s t r u c t -

61

ure,

n o n - d e s t r u c t i v e materials investigation and - last not least - for active-

tion

analysisl2!.^4'211·212.

section of accelerating tube

[(

Fig. 3.1:

Η — Η. Γ"Ι

ιi

Schematic r e p r e s e n t a t i o n of a van de G r a a f f - g e n e r a t o r for acceleration of electrons

3.2.2

Linear accelerator

For photon activation analysis p u r p o s e , utilised.

Therefore,

mostly linear accelerators have been

this machine type is here described in more detail

than

the other a c c e l e r a t o r s . Among the cyclic machines the linear accelerator, o r "linac", imply the

was developed

also briefly called

"lineac"

f i r s t . The term "linear accelerator" does not only

fact that particles a r e accelerated along s t r a i g h t

trajectories,

but

also the application of a high f r e q u e n c y source to produce a wave with help of which

the

particles

are carried

to their

final

energy.

The

first

theoretical

considerations were published in 1924 2 *·'; the f i r s t operating linac was r e p o r t ed in 1928 2 1 4 . In the early 1930~s machines were built which could produce more than 1 MeV maximum e n e r g y for mercury ions 2 *'' and up to 2.5 P.leV for electrons (Ref

s.-216"219).

62

In the analytical context the early experiments of Coates 2 2 ^ are of some interest; radiation was analysed which originated from bombardment of several target elements with Hg-ions,

not v e r y successfully due to the lack of high perform-

ance radiation spectrometry equipment at that time.

In the middle of the 1930's the further development of the linac intermediately stopped in a stadium of prematurity because of the lack of high frequency generators with high output power. neously -

Moreover,

the cyclotron and - almost simulta-

the betatron was developed at that time and thus the "linear" idea

was abandoned

in favour of the " c i r c u l a r " .

The linac principle reentered

the

scene when the desired high-power frequency source, namely the klystron, was invented.

Its development was pushed foreward during World War II under the

pressure of radar protection. The klystron was announced and developed by different

groups22*.

Major development work on high frequency sources and linear accelerators was performed by the linac research group at Stanford,

U . S . A . . The first linac at

Stanford provided a maximum electron energy of 4.5 MeV. Later on,

series of

progressively larger linacs were built to finally achieve an electron energy of more than 20 G e V 2 2 2 " 2 2 4 . Barely any of these machines would have met the requirements of

photon

activation

analysis;

it

is not

known

to the authors,

if it

was e v e r attempted to use any of the Stanford machines for analytical purpose. These machines were designed to serve physical research purpose exclusively.

Also other research groups have developed and constructed linear accelerators (Ref's.222-228),

but the most relevant work on electron linear accelerators was

undoubtedly performed at Stanford. 3.2.1.1

General description

A linear accelerator is represented schematically in F i g . 3 . 2 . celerated

along

straight

trajectories

supplied by a radiofrequency along

the axis of

by

alternating

Electrons are ac-

electromagnetic

fields

( r f ) system. These fields are made to propagate

a cylindrical

structure.

The

rf

system

consists of

an

rf-

generator which supplies microwaves of highly stable frequencies of several gigacycles per second.

The power of the microwaves is amplified (up to several

tens of megawatts peak power) by a high power klystron. Frequently a multiplestep power amplification system is used.

63

Mode transformer

Fig.

3.2:

Schematic representation

of a travelling wave linear accelerator for

electrons with a single accelerator tube section

The electron source (electron gun) basically consists of a heated metal or metal oxide from which the electrons are emitted. These are extracted from the source region and focussed by electrodes and then injected into the buncher region of the accelerator. The electron gun - as well as the rf-system - is designed for pulsed operation at repetition rates selectable from a few cycles per second to maximally several thousand. The pulses feeding the electron gun and the microwave amplifier are provided by a high power modulator driven by a mas t e r pulse generator. Pulsed operation is necessary because of the excessively large power required in electron accelerators. The microwave amplifier can provide the excessively large rf-power only in pulsed operation at relatively low duty cycle. The electron beam,

before being injected into the buncher section,

has to be

well colümated, and it must be homogeneous in energy to avoid too large spread during acceleration.

Actually,

the solid angle of injection must not exceed se-

veral thousandths of a steradian.

The sharp focalisation of the electron beam

is realised by focus coils which surround the accelerator tube in the buncher

64 region. In some linacs, focussing coils are provided over the entire length of the accelerating tube. The injection is performed at an energy selected so that the electrons are readily captured by the electric field within the accelerating section of the linac; usually it is some tens to several hundreds of keV. The wave mode of the accelerating microwave supplied by the klystron, before being t r a n s f e r r e d to the accelerating tube, is converted by a mode transformer. Hereby it is transformed so that its electric field vector coincides with the beam direction. The accelerating s t r u c t u r e s are specially designed waveguides. These allow continuous energy transfer from the electromagnetic wave to the electrons up to the desired value. A waveguide is a metal duct which is evacuated or filled with a dielectric. Under certain conditions electromagnetic waves can propagate through it, "guide d " by the metal wall. In electron accelerators, discs containing circular holes in the center stances

within the accelerator

tube.

waveguides are supplied with

( " i r i s e s " ) placed at certain di-

The phase velocity of the

accelerating

wave increases with the distance of the irises (if there were no irises provided the phase velocity would exceed light velocity and thus become unsuitable for particle acceleration). These "loaded" waveguides enable the formation of a travelling wave to carry electrons to their final energy,

maximally about 20

GeV hitherto, for photon activation analysis optimally around 30 MeV ( s e e above and in C h . 2 ) . Out of the electrons injected into the buncher section only those are captured by the travelling wave which " s e e " its proper phase whilst all residuals are discarded. stances ling

The irises within the buncher area are arranged in increasing di-

so as to obtain continuously increasing phase velocity of the travel-

wave

up

to nearly

light

velocity.

Thereafter

the irises

normally

are

equidistant until the electron window at the end of the accelerating tube. Any further energy increase after the buncher section s e r v e s only for relativistic mass increase of the electrons near light velocity. At the end of the accelerating tube the electron beam is transmitted through a beam window which usually consists of a thin metal foil, e . g . titanium. Bremsstrahlung is produced by absorption of the electron beam in a target of high Ζ material whereby a part of its energy is converted to X-radiation. The bremsstrahlung production mechanism is discussed in 3.5 below.

65 3.2.2.2

The linear accelerator used in the p r e s e n t work

The machine used for this work is discussed only briefly h e r e , emphasising the data and facts which are relevant

for photon activation a n a l y s i s .

A detailed

description of t h e accelerator is given in the BAM Linac R e p o r t 5 5 . A schematic representation

of

the

electron

linear

accelerator

of

the

Bundesanstalt

für

Materialprüfung is given in F i g . 3 . 3 .

Bremsstrahlung

Converter

(Target I

Fig. 3.3: Schematic r e p r e s e n t a t i o n of the BAM Linac

a) The accelerating waveguide In this machine the accelerating waveguide is divided into two sections.

This

is done for the following reason:

A continuous acceleration of electrons in a

linear

obtained

accelerator

could

only

be

by

a

quasi-constant

accelerating

field s t r e n g t h along the entire waveguide. However, the field s t r e n g t h d e c r e a s es rapidly along the accelerating

path due to losses t h r o u g h resistance and

continuous e n e r g y t r a n s f e r to the electrons to be accelerated. T h e r e f o r e , continuous

accelerating

path length

and thus the achievable output

the

electron

e n e r g y of this system is limited to about two meters or about 17 MeV, r e s p e c t ively. F u r t h e r e n e r g y increase can be obtained only by a s u b s e q u e n t waveguide section with its own rf power s u p p l y . In the described machine one r f - s y s t e m .

66 equipped with a power divider (or a t t e n u a t o r ) , supplies both waveguide sections with the r e q u i r e d e n e r g y . shifter.

The

first

The sections are coupled electrically with a phase

section operates at constant

power providing electrons of

about 17 MeV. By p r o p e r setting of the phase s h i f t e r the electron e n e r g y inc r e a s e s continuously to a maximum value of about 35 MeV. The phase s h i f t e r can also be set so that the electrons "see" a r e v e r s e d electric field and t h u s are decelerated.

The actual value of acceleration or deceleration is determined by

the input power of the second waveguide section which is selectable with help of the power a t t e n u a t o r . In F i g . 3 . 4 t h e electron output e n e r g y as a function of the electron beam c u r r e n t is shown, whereby the g r a p h s 1 to 9 r e p r e s e n t the e n e r g y at d i f f e r e n t input powers of the second waveguide section. The dashed line is valid for maximum input power. T h u s , the final electron e n e r g y is continously selectable from about 4 to about 35 MeV.

Fig. 3.4: Load c u r v e s of the BAM Linac; relationship between electron output c u r r e n t and e n e r g y (T = peak c u r r e n t ; I = mean c u r r e n t ) ; parameter = input power of the second waveguide section

67 Assuming

40 keV injection e n e r g y

of t h e e l e c t r o n s ,

t h e i r velocity is 0,37

c.

T h e y a r e t h e n a c c e l e r e a t e d t o a b o u t 0,99 c . Any f u r t h e r e n e r g y i n c r e a s e a p p e a r s a s r e l a t i v i s t i c mass i n c r e a s e . To avoid u n d e s i r a b l e s p r e a d of t h e e l e c t r o n s

the

e n t i r e w a v e g u i d e is s u r r o u n d e d b y f o c u s s i n g coils.

The

accelerator

is equipped

with

a beam

steering

system

containing

special

s t e e r i n g coils a n d a m a g n e t i c q u a d r u p o l e l e n s at t h e e n d of t h e w a v e g u i d e . b ) t h e rf - s y s t e m T h e rf e n e r g y i s p r o d u c e d b y a commercially a v a i l a b l e f i v e - c h a m b e r r a d a r k l y s t r o n with a p e a k o u t p u t p o w e r of 24 MW (mean v a l u e : 24 kW; a c t u a l l y , a multiple s t e p s y s t e m c o n t a i n i n g a h i g h f r e q u e n c y o s c i l l a t o r , a d r i v e r k l y s t r o n a n d t h e mentioned main k l y s t r o n is u s e d ) . T h e k l y s t r o n i s e q u i p p e d with two p o w e r o u t p u t s of 12 MW peak power e a c h . T h e r f - s y s t e m ( a s well a s t h e e l e c t r o n g u n ; s e e below)

is

pulsed

at

repetition

rates

s e l e c t a b l e in s t e p s

from 12.5 u p to 300

s " l . T h e p u l s e l e n g t h of t h e microwave i s 4 u s .

The output through

power of t h e k l y s t r o n

waveguides

is t r a n s f e r r e d

with r e c t a n g u l a r

t o both a c c e l e r a t o r

cross section;

sections

the f i r s t accelerator

sec-

tion o p e r a t e s a t a c o n s t a n t i n p u t power (PI) of 12 MW ( p e a k v a l u e ) . As s h o r t l y mentioned a b o v e ,

at t h e e n t r a n c e of each a c c e l e r a t o r section t h e e l e c t r i c field

v e c t o r of t h e microwave i s r o t a t e d b y 90° b y a mode t r a n s f o r m e r so t h a t i t s d i rection guide

is parallel section

to the electron a

power

maximum of 12 MW peak v a l u e

(PII).

c) t h e e l e c t r o n

operates

at

beam a x i s .

T h e second

selectable

with

the

accelerating attenuator

up

waveto

a

source

In t h e e l e c t r o n g u n e l e c t r o n s a r e p r o d u c e d b y a h e a t e d tantalum d i s c . T h e d i s c i s h e a t e d t h r o u g h b o m b a r d m e n t with e l e c t r o n s which a r e emitted from a hot t u n g s t e n wire a n d d i r e c t e d to t h e tantalum d i s c b y a s t a t i c v o l t a g e of 6 k V . T h e e l e c t r o n s emitted b y t h e tantalum d i s c a r e e x t r a c t e d from t h e e l e c t r o n g u n pulsed (see above) high voltage (-40 kV), the d r i f t - t u b e having zero potential. T h e e l e c t r o n s o u r c e i s sealed in a g l a s s t u b e which is d i r e c t l y a t t a c h e d t o t h e mode t r a n s f o r m e r a t t h e f i r s t a c c e l e r a t o r s e c t i o n .

F u r t h e r r e c o m m e n d e d l i t e r a t u r e a b o u t e l e c t r o n l i n e a r a c c e l e r a t o r s can be f o u n d in R e f ' s . 5 5 · 6 9 · 7 6 · 1 1 6 · 1 2 2 , 2 2 9 - 2 3 2 , 682_

68 3.2.3

Betatron

The b e t a t r o n ,

a circular accelerator designed to accelerate electrons, is a de-

velopment logically following the cyclotron invented 2

Theoretical considerations

of Wideröe *'* inspired

by Lawrence in

Lawrence

1930 2 3 3 .

to the idea of a

c i r c u l a r particle p a t h . Until the end of World War II cyclotrons were the only devices to produce high ion energies up to about 40 MeV. Since cyclotrons cannot be used for photon activation analysis they a r e just mentioned here and not discussed f u r t h e r . Going out from the cyclotron

principle the development of the betatron

was

s t r a i g h t f o r w a r d . The basic principles were established - i n d e p e n d e n t l y from one a n o t h e r - by Wideröe and by Slepian. The l a t t e r , in his U . S . p a t e n t 2 3 ^ ,

sug-

gested the operation principle of the b e t a t r o n . The first successfully operating betatron was built in 1935; electron e n e r g i e s up to 1.8 MeV were achievable b y this machine. In the beginning of the 1940's it was D. W. Kerst who was the f i r s t to cons t r u c t a b e t a t r o n which provided a beam c u r r e n t output in the microampere r e 9Q gion at comparatively high maximum electron energies, namely up to 2.3 M e V " ' 100,235,236^ stability Excellent

237

He

als0)

together

with

Serber,

evaluated

the

theory

of

orbit

.

detailed

descriptions

of the

23

historical development

of the

betatron

23

were given by Kopfermann ® and Wideröe ®. The schematic design of a betatron is p r e s e n t e d in F i g . 3 . 5 .

The accelerator

consists of a magnet fed by alternating c u r r e n t of a f r e q u e n c y normally between 50 and 200

A vacuum chamber is placed in the magnet gap (because of its

shape the vacuum chamber usually is called " d o u g h n u t " ) . In this chamber the electrons a r e made to circulate. The magnetic field has a two-fold p u r p o s e : 1 - The magnetic field p r e s e n t in the doughnut e x e r t s a Lorentz force upon the electrons,

which points towards the c e n t e r of the doughnut and so forces

t h e electrons on a circular o r b i t . 2 - The magnetic flux linked to the doughnut c h a n g e s in time, and induces an electric field whose force lines form concentric circles orthogonal to the

69

axis of symmetry.

roil

VO Ια»

Hoiiohnnf

F i g . 3.5: Schematic representation of a betatron

One of these circular force lines is the "central orbit" of the electrons.

This

electric field accelerates the electrons. The

betatron

basically can be regarded as the analog of a transformer

whose

primary current is the alternating current which excites the magnet and whose secondary current is the electron current circulating in the vacuum chamber. Since ated

the induced in

the

electric

half-cycle

of

field

is alternating

increasing

field

electrons can only

strength.

Therefore

be

the

accelerelectrons

circulate only f o r a half-period of the alternating current or less. Thus the

70

machine r u n s at pulsed operation whose repetition rate coincides with the c u r r e n t f r e q u e n c y ; the electrons a r e injected when the magnetic field is zero (or nearly z e r o ) . The beam is e x t r a c t e d (or used in any o t h e r desired manner) when t h e field has reached its maximum value (otherwise, in the case of f u r t h e r p r e sence in the electric field the electrons would be d e c e l e r a t e d ) .

Bremsstrahlung

is produced by absorption of the electron beam by a heavy metal target 3 . 2 . 2 ) e i t h e r internally

(see

(within the vacuum chamber) o r externally a f t e r ex-

traction t h r o u g h an electron beam window. Betatrons a r e used for energies between five and several t e n s of MeV ( t h e largest b e t a t r o n c o n s t r u c t e d h i t h e r t o has a maximum e n e r g y o u t p u t of 300 MeV). For lower energies,

electrostatic machines ( e . g .

van de Graaff accelerators)

are

more c o n v e n i e n t . Higher energies would r e q u i r e excessively large magnets and t h e r e b y r e n d e r t h e machine too costly. The theoretical e n e r g y limit is reached when the e n e r g y increase d u r i n g acceleration equals the losses by

radiation

damping. This is t h e case at approximately 500 MeV. For photon activation betat r o n s of more than say 30 MeV electron e n e r g y output a r e not n e c e s s a r y or even unsuitable for t h e already mentioned reasons ( u n d e s i r a b l e nuclear reactions; no appreciable electron beam c u r r e n t s ; beam c u r r e n t s a r e lower than those achievable in comparable linear accelerators by about two o r d e r s of magnitude;

see

above). Low e n e r g y

b e t a t r o n s a r e f r e q u e n t l y applied in medicine (tumor

treatment).

Higher e n e r g y (around 20 MeV and more) machines a r e mainly used in the field of material r e s e a r c h and investigation ( X - r a y d i f f r a c t i o n , r a d i o g r a p h y ) or photon activation. For more detailed information about the use of b e t a t r o n s in photon activation analysis the r e a d e r might r e f e r to R e f ' s 2 5 · 5 7 · 1 0 8 · 1 1 0 · 1 4 4 · 1 9 4 · Unwanted

photon

activation

during

betatron

irradiation

240-262

was

and C h . 6 .

discussed

by

K u t t e m p e r o o r 2 4 5 , 9 8 1 and T u c h s c h e e r e r 2 6 3 . 3.2.4

Microtron

The above mentioned limitations of the b e t a t r o n , namely limited e n e r g y and beam c u r r e n t can be overcome - besides using a linac - by the microtron. The concept of the microtron was established

1945 by V e k s l e r 2 6 4 - 2 6 7 .

The f i r s t operating

microtron was r e p o r t e d in 1948 in Ottawa, Canada 2 ® 8 " 2 7 *. F u r t h e r development work was performed by Kaiser in the beginning of the 1 9 5 0 ' s 2 7 2 " 2 7 4 . These machines yielded maximum electron e n e r g i e s around 6 MeV. The f i r s t microtron with

71

comparably high electron energy (about 30 MeV) was constructed 1953 in London (Ref's.275"279). The microtron is represented schematically in F i g . 3 . 6 . The electrons are accelerated by a f i x e d - f r e q u e n c y resonant cavity and are made to move in a constant magnetic

field

where they describe

circular

trajectories

with increasing

rad-

ius. The orbits are tangential to the axis of the c a v i t y .

Magnet Coil

Yoke

Pole

Electron Gun

F i g . 3 . 6 : Schematic representation of a microtron The special advantages of the microtron are the relatively simple construction, the easy deflectability of the electron beam and its excellent energy homogen-

72 e i t y . Moreover,

achievable energies and electron beam c u r r e n t s are in the r e -

gion of medium energy linear accelerators,

namely several tens of MeV at mean

beam c u r r e n t s of about 100 μΑ. The values ideally meet the requirements of photon activation analysis. A certain

problem of the microtron is the vertical beam instability since the

quasi-homogeneous magnetic field in the vacuum chamber does not enable any v e r tical focussing. across

Moreover, the focussing effect during transit of the electrons

the resonant

cavity is limited.

Thus the tolerance values in the con-

struction of the magnet are extremely small and thus the machine might render costly,

in particular if large energies are required as is the case in photon

activation analysis. Microtrons which most favourably meet the requirements of photon activation analysis were reported by K a p i t s a 2 8 0 ' 8 4 liant energy

and B a c i u 2 8 * ' 2 8 2 .

homogeneity and easy-to-perform

Because of its bril-

extractability

of the beam

the

microtron can be used most advantageously as injection source for l a r g e r accelerators.

For photon activation

analysis,

however,

the microtron,

in spite of

the convincing advantages mentioned above, has not gained as much importance and widespread application as sometimes was predicted; see e . g .

Ref.''".

Because of some similarity

to the cyclotron

frequency in one resonant

cavity in a constant magnetic field along circular

trajectories)

the

microtron

sometimes

is

(acceleration by a constant

called

"electron

" t r u e " electron cyclotron was built in 1952 by S a l o w

284

high

cyclotron"283.

A

. However, this machine

can produce only very low electron energies and so never has been used but for demonstration purpose. For more information about the microtron and its use in photon activation analysis, the reader might r e f e r to R e f . ' s 2 5 · 1 9 4 ' cently, tron

280

>

281

·

283

'

2 8 5 - 3 0 0

and C h . 6 . Re-

Kapitsa et al. published a survey article about the use of the micro-

for photon

activation

analysis in the

USSR

(Kapitsa et a l . " 8

and

the

literature cited t h e r e i n ) . 3.2.5

Other electron accelerators

T h e r e are two other kinds of electron accelerators which can be used for photon activation analysis, Whilst the f o r m e r

30

namely the synchromicroton and the electron '·"

303

synchrotron.

- as far as the authors know - has hitherto not been

used for activation analysis purpose, the use of the latter has been reported

73 surprisingly

often^·"·

304-307_

eously by three g r o u p s ' * ^ '

This

machine was developed

quasi-simultan-

in 1945. It is designed to produce electrons

of extremely high energies and therefore basically is not suitable for photon activation analysis. However, the workers cited above reported special applications at high (70 MeV and more) e n e r g i e s . This kind of accelerator is not r e commendable for routine activation analysis.

74 3.3

P r o d u c t i o n a n d p h y s i c a l p r o p e r t i e s of b r e m s s t r a h l u n g

T h e p r i m a r y r a d i a t i o n almost e x c l u s i v e l y u s e d f o r p h o t o n a c t i v a t i o n a n a l y s i s i s b r e m s s t r a h l u n g ( X - r a d i a t i o n , X - r a y s ) which i s p r o d u c e d b y s t o p p i n g an e l e c t r o n beam from an a c c e l e r a t o r in a h e a v y metal d i s c . A c e r t a i n p o r t i o n of t h e elect r o n e n e r g y is converted into photons,

t h e r e s t i s d i s s i p a t e d in t h e

converter

a s h e a t . A b r e m s s t r a h l u n g p h o t o n i s p r o d u c e d when an e l e c t r o n i n c i d e n t on an atom

of

the

nucleus.

converter

material

interacts

with

the

electrostatic

it i s d e f l e c t e d from t h e s t r a i g h t

of

From e l e c t r o d y n a m i c s it is well known

a n a c c e l e r a t e d e l e c t r i c c h a r g e emits e l e c t r o m a g n e t i c r a d i a t i o n . speaking,

the

the

electron

p a t h which c o r r e s p o n d s to a n a c c e l e r a t i o n

the direction towards the nucleus. nically

field

U n d e r t h e i n f l u e n c e of t h e a t t r a c t i v e f o r c e a c t i n g u p o n t h e

interaction

of

the

electron

with

the

Quantum electric

in

that

mecha-

field

re-

s u l t s in t h e emission of a p h o t o n and a c o r r e s p o n d i n g e n e r g y loss of t h e e l e c tron.

3.3.1 Since

T h e s p e c t r u m of t h e b r e m s s t r a h l u n g p h o t o n s ( X - r a y the

radial acceleration

of t h e e l e c t r o n

spectrum)

d e p e n d s on i t s o r b i t

relative

to

t h e n u c l e u s a n d t h e o r b i t s r a n d o m l y d i s t r i b u t e d we e x p e c t a l r e a d y in t h e f r a m e work of c l a s s i c a l e l e c t r o d y n a m i c s t h a t t h e s p e c t r u m of emitted p h o t o n s i s c o n tinuous. emitted

If but

the in

bremsstrahlung

electron the

case

is

only

of

a nearly

slightly

deflected

central

a low

collision

with

energy the

photon

nucleus

p h o t o n c a r r i e s almost t h e t o t a l initial e l e c t r o n e n e r g y

is the

leaving

t h e e l e c t r o n with a v e r y low k i n e t i c e n e r g y . From t h i s simple a r g u m e n t we d e d u c e t h a t t h e e n e r g y of b r e m s s t r a h l u n g p h o t o n s r a n g e s from z e r o u p t o a maximum v a l u e which e q u a l s t h e e n e r g y of t h e i n c i d e n t e l e c t r o n s . chanical calculations

yield t h e same r e s u l t .

In f a c t , q u a n t u m me-

We also e x p e c t t h a t t h e

probabili-

t y of weak d e f l e c t i o n s i s much h i g h e r t h a n t h a t of s t r o n g d e f l e c t i o n s b e c a u s e t h e n u m b e r of e l e c t r o n p a s s i n g t h e n u c l e u s a t a l a r g e d i s t a n c e i s g r e a t e r t h a n t h e n u m b e r of close e n c o u n t e r s . T h e c o n t r i b u t i o n of low e n e r g y p h o t o n s t o t h e t o t a l b r e m s s t r a h l u n g i n t e n s i t y i s i n d e e d much h i g h e r t h a n t h a t of high

energy

p h o t o n s n e a r t h e maximum e n e r g y . F i g . 3 . 7 shows t h a t t h e s p e c t r u m c o n t i n u o u s l y declines

with i n c r e a s i n g

photon

energy

down t o z e r o at t h e maximum

energy

( e l e c t r o n e n e r g y ) . T h e s p e c t r u m also d e p e n d s on t h e p h o t o n emission a n g l e with respect

to the

direction

of t h e i n c i d e n t

electrons.

With i n c r e a s i n g

angle

the

i n t e n s i t i y r a p i d l y d r o p s f o r all p h o t o n e n e r g i e s a n d t h e s p e c t r u m becomes s o f t e r b e c a u s e t h e d e c r e a s e with emission a n g l e i s more p r o n o u n c e d f o r high

than

f o r low e n e r g y p h o t o n s . In F i g . 3 . 8 t h e same plot is shown f o r 60 MeV e l e c t r o n s i m p i n g i n g on a t h i c k t u n g s t e n t a r g e t . We notice t h a t a t 60 MeV f o r all p h o t o n

75 e n e r g i e s the number of emitted photons is h i g h e r than at 30 MeV electron gy.

Moreover,

forward

Fig.

direction.

3.7:

Bremsstrahlung

s p e c t r u m produced in a thick t u n g s t e n

MeV e l e c t r o n s at d i f f e r e n t emission

shows

falls o f f ,

then

t h a t at

small a n g l e s

slowly d e c r e a s e s

t h e total

target

by 30

angles

T h e a n g u l a r d i s t r i b u t i o n function is obtained by i n t e g r a t i n g ο ι η oil d i f f e r e n t emission a n g l e s o v e r the photon e n e r g y 0 1 " ' J . Fig.3.9

ener-

t h e b r e m s s t r a h l u n g i n t e n s i t y is c o n s i d e r a b l y more peaked in the

bremsstrahlung

for medium a n g l e s and

the

spectra

intensity

near 90° t h e

for

rapidly intensity

again s h a r p l y r i s e s and than remains n e a r l y c o n s t a n t t h r o u g h o u t t h e major part o f t h e b a c k w a r d h e m i s p h e r e . T h e only marked c h a n g e at h i g h e r electron e n e r g y is the

increasing

(Fig.3.10).

forward

direction

T h i s means that the half width of the a n g u l a r distribution

slope

of

the

angular

decreas-

e s with i n c r e a s i n g e l e c t r o n e n e r g y

distribution

near

the

- or in o t h e r words - t h a t the total photon

i n t e n s i t y becomes more c o n c e n t r a t e d at small a n g l e s .

In F i g . 3 . 1 1 a measured

76

Fig. 3.8: B r e m s s t r a h l u n g spectrum produced in a thick t u n g s t e n t a r g e t by 60 MeV electrons at d i f f e r e n t emission angles

Fig. 3 . 9 : Angular distribution of 30 MeV b r e m s s t r a h l u n g produced in t u n g s t e n t a r g e t s with various t h i c k n e s s e s

77

F i g . 3 . 1 0 : Angular distribution of 60 MeV bremsstrahlung produced in tungsten t a r g e t s with various thicknesses

V

ε = 29 1eV

\

1

1 1 1 1 1 1 1 i l l

60 cm

V

\ ι Μ

1

ι

1

-5

ι

0 Ψ

1 1 1 1 1 1 1 III *5

1 1 deg

—'

Fig 3 . 1 1 : Bremsstrahlung beam profile for 29 MeV electrons measured by activation of copper

78

beam profile is plotted f o r 29 MeV e l e c t r o n s absorbed in a thick tantalum converter.

The photon

flux was determined

from the activation of small copper

discs a r r a n g e d in a plane p e r p e n d i c u l a r to t h e forward direction at a distance of 60 cm from the b r e m s s t r a h l u n g c o n v e r t e r . From the measured profile we conclude that the half-width of the a n g u l a r distribution of photons

contributing

t o the activation of copper is only about 3 . 5 ° . This means that in practical photon activation analysis work the large photons flux gradient of the bremss t r a h l u n g beam near t h e c o n v e r t e r must be taken into a c c o u n t . The sample and t h e r e f e r e n c e material must be aligned as carefully as possible on the axis of t h e b r e m s s t r a h l u n g cone in o r d e r to e n s u r e identical irradiation conditions for t h e sample and t h e r e f e r e n c e material and a homogeneous activation of t h e material. The flux gradient p e r p e n d i c u l a r to the beam axis is smaller at l a r g e r dis t a n c e s from t h e c o n v e r t e r but t h e r e the i n t e n s i t y is poor because the photon flux density

d e c r e a s e s inversely proportional to the s q u a r e of the distance οι ο from the c o n v e r t e r . T h e r e f o r e usually a maximum distance of a few centimeters between the c o n v e r t e r and the irradiation position is c h o s e n . The difficulties due to t h e high t r a n s v e r s a l flux gradient can only be overcome by controlling t h e position of the electron beam - and t h e r e b y of t h e photon beam during

irradiation.

Using

the steering

elements of the accelerator the beam

axis can be a d j u s t e d in o r d e r to coincide with the c e n t e r of the sample.

The

beam position is monitored by optical beam viewers or by induction monitors. 3.3.2

B r e m s s t r a h l u n g efficiency

The conversion efficiency between electron beam power and t h e power radiated as b r e m s s t r a h l u n g photons d e p e n d s on t h e electron e n e r g y and the material as well a s the t h i c k n e s s of the c o n v e r t e r . for a tungsten

converter

is plotted

In Fig.3.12 the b r e m s s t r a h l u n g efficiency as a function of the ratio between

the

c o n v e r t e r t h i c k n e s s determined by the competition between production and r e a b sorption of b r e m s s t r a h l u n g photons. If the c o n v e r t e r is thin only a small numb e r of incident electrons c o n t r i b u t e s to b r e m s s t r a h l u n g production whereas t h e major p a r t of the electron beam t r a n s v e r s e s the material. With increasing conv e r t e r t h i c k n e s s the number of photon producing interaction i n c r e a s e s but also t h e attenuation of the photon flux by the c o n v e r t e r material r i s e s . In the case of a v e r y thick c o n v e r t e r the electron beam is completely a b s o r b e d t h u s p r o d u cing the maximum achievable b r e m s s t r a h l u n g f l u x . But the photons a r e heavily a t t e n u a t e d in t h e s u b s e q u e n t layers so that the net photon flux emerging from t h e c o n v e r t e r is low. T h e r e f o r e ,

an optimum c o n v e r t e r t h i c k n e s s exists from

which the b r e m s s t r a h l u n g efficiency r e a c h e s maximum. The optimum t h i c k n e s s c o r r e s p o n d s approximately to half t h e electron r a n g e .

converter

79

F i g . 3.12 shows that for 30 MeV electrons - which is a favourable e n e r g y

for

photon activation analysis (see C h . 2 ) - the maximum efficiency is about 0,4.

Fig.

3.12:

Efficiency of bremsstrahlung

production in tungsten;

ratio between

the total bremsstrahlung photon energy and the electron energy as a function of the target thickness and the electron e n e r g y

T h e r e f o r e 40 % of the incident electron beam power is converted into electromagnetic radiation whereas 60 % is dissipated in the material as heat. From these f i g u r e s it is clear that a bremsstrahlung converter must be well cooled.

Since

the beam power of electron accelerators used in photon activation analysis may be as high as 10 kW cooling may become a difficult problem because a thermal

80 power of several kW must be removed from a small volume. Therefore, the total bremsstrahlung converter is often divided into several metal discs cooled by an intense water or air flow. The most commonly used converter materials are the heavy elements tantalum, tungsten, platinum and gold. Heavy metals are preferred because the bremsstrahlung efficiency increases with increasing atomic number of the converter material. In Fig.3.13 a comparison between three converter materials is given for 35 MeV electrons.

Fig. 3.13: Specific activity induced in carbon by 35 MeV bremsstrahlung produced through electron absorption in various metals as a function of the bremsstrahlung converter thickness

81

The flux d e n s i t y of b r e m s s t r a h l u n g photons in t h e forward direction is measured 12 11 u s i n g the activation of carbon via the reaction C ( y , n ) C. The r e s u l t i n g c u r v e shows that t h e r e is indeed an optimum c o n v e r t e r t h i c k n e s s yielding the maximum induced a c t i v i t y .

Fig. 3.14: Electron r a n g e in various heavy metals a s a f u n c t i o n of the electron e n e r g y (p = d e n s i t y of the t a r g e t material)

For aluminium, copper and platinum c o n v e r t e r s this value is a r r o u n d 4 g/cm^ which is much less than t h e electron r a n g e in t h e material (see Fig. 3.14) at 35 MeV. Qualitatively

this is consistent with the theoretical c u r v e s in Fig. 3.12.

The d i f f e r e n c e between

the theoretical and

the measured optimum

converter

t h i c k n e s s can be explained by the fact t h a t in the activation measurement only high e n e r g y photons above t h e reaction t h r e s h o l d c o n t r i b u t e whereas t h e t h e o r e tical calculation t a k e s into account all b r e m s s t r a h l u n g photons. Comparing t h e

82 yield curves in F i g . 3 . 1 3 for Al, Cu and Pt we conclude that the heaviest converter material Pt is the best choice. F i g . 3 . 1 5 shows the increase of the optimal thickness of a platinum target with the electron energy for

(Y,n)-react-

ions.

F i g . 3.15: Optimum thickness of a platinum bremsstrahlung converter a s a function of the electron energy for (Y.n)-reactions

In the design of a suitable bremsstrahlung converter for photon activation anal y s i s an additional aspect must be taken into ac-count. If the converter has the optimum thickness with respect to maximum activation of the sample a large portion of the electron beam will be transmitted through the converter because the optimum thickness is smaller than the electron range. The transmitted electrons can reach the irradiation position and dissipate their residual energy in the sample. Under unfavourable conditions the sample or even the irradiation

83

setup can thus be destroyed. To avoid any damage of the material the use of a cleaning magnet between the converter and the irradiation position is feasable which separates the electrons from the bremsstrahlung beam by deflecting them in the direction towards of a beam dump. This arrangement requires considerable space between the converter and the sample to be irradiated and then the activating bremsstrahlung flux density at the sample is poor. As f a r as the authors know, a cleaning magnet has hitherto not been used in photon activation analysis. Often the other alternative has been p r e f e r r e d . In order to absorb the total

electron

beam

one

selects

the

converter

sufficiently

thick.

Usually

the

thickness is chosen to be slightly greater than the maximum electron range at the highest e n e r g y to be used for activation. F i g . 3.13 shows that the resulting high e n e r g y

photon flux contributing

to the activation of the sample is only

about a factor of two smaller than the maximum value. From the point of view of available activating

flux

at the sample position it is much better to place the

sample at a distance of a few centimeters behind a thick converter than at several tens of centimeters (required for the deflection magnet) from an optimum c o n v e r t e r . Yet another wayout is the use of an optimum converter and the removal of

the

residual

electrons

by

a light

material

(e.g.

aluminium)

absorber.

Several workers have applied this technique in photon activation analysis

(see

Ch.6).

Further recommended literature about the production and properties of bremsstrahlung can be found in R e f s . 8 7 ' 1 6 2 > 3 1 2 ~ 3 1 8 .

84

3.4

The b r e m s s t r a h l u n g c o n v e r t e r as a n e u t r o n source

A fraction of t h e b r e m s s t r a h l u n g photons produced in the c o n v e r t e r i n t e r a c t s with t h e c o n v e r t e r material by photonuclear r e a c t i o n s . Since the ( γ , χ η ) r e a c tions have a relatively high effective cross section the b r e m s s t r a h l u n g convert e r is always a n e u t r o n source with a considerable i n t e n s i t y . The neutron yield d e p e n d s upon t h e electron e n e r g y and on t h e material and the t h i c k n e s s of the c o n v e r t e r . Since both the b r e m s s t r a h l u n g efficiency and t h e e f f e c t i v e photoneut r o n cross section increase as a function of the electron e n e r g y the neutron yield rapidly i n c r e a s e with increasing electron e n e r g y

(Fig. 3 . 1 6 ) .

The relat-

ionship between t h e n e u t r o n yield and the c o n v e r t e r t h i c k n e s s has saturation c h a r a c t e r . For a thin c o n v e r t e r most of t h e b r e m s s t r a h l u n g photons emerge from t h e material wihout nuclear interaction.

d/R

F i g . 3.16: Photoneutron yield of a tantalum t a r g e t a s a function of the t a r g e t t h i c k n e s s for various electron e n e r g i e s ;

the dashed lines

t h e asymptotic values for infinite target

thickness.

indicate

YR (Yield) i s

t h e total neutron source s t r e n g t h per electron beam power u n i t .

85

The number of photoneutron reactions induced by the bremsstrahlung increases with increasing layer thickness. For thick converters however most of the photons are reabsorbed inside the material so that no significant increase of the photoneutron

reaction

rate is possible in the following layers.

F i g . 3.15 shows

that 90 % of the saturation value of the neutron yield is reached at a converter thickness which is much larger than the electron range.

For typical working conditions of a photon activation analysis facility: - electron e n e r g y

:

30 MeV

- electron beam power : - converter material

3 kW

:

tantalum

- converter thickness :

1 - 2 χ electron range

the

will

12 -1 photoneutron

yield

be about

3 ·

10

s

.

This

is a

comparatively

strong neutron source. In

Fig. 3.17

ters are

calculated

plotted

asymptotic

as a function of

neutron

yields

the electron

for infinitely

energy

thick

f o r various

conver-

materials.

Above 10 MeV the yield rapidly rises up to about 25 MeV. For electron e n e r g y above 40 MeV the neutron pro-duction rises v e r y slowly. Since bremsstrahlung efficiency and

e f f e c t i v e photoneutron

cross

sections

increase

with the atomic

number of the converter material the heavy metals yield is especially high due to photofission (see

Ref's.

and

311'319

"

neutron 324

multiplication

caused

by

neutron-induced

fission

).

The e n e r g y distribution of photoneutrons can be interpreted on the basis of the 41 Ο neutron evaporation model . The high e n e r g y part of the spectrum is well described by a Maxwellian distribution with an e f f e c t i v e nuclear temperature between 0,5 MeV and 1,5 MeV depending on the electron e n e r g y and the material. Around 1 MeV the spectrum has a maximum and rapidly decreases towards higher neutron e n e r g i e s . At

higher

The spectral shape is similar to that of a fission spektrum.

neutron energies

distribution

due

to the

the spektrum

deviates from the simple Maxwellian

contribution of direct

neutron emission.

The

average

converter

is often

neutron energie is a few MeV (typically 2 M e V ) . In

photon

activation

analysis facilities the bremsstrahlung

surrounded by shielding material in which the primary neutron emerging from the converter

are scattered

and moderated

(see F i g ' s . 3.18a and b ) .

Therefore a

large flux density of low energy neutrons can be observed at the irradiation

86

position giving rise to neutron capture reactions in the sample.

Fig.

3.17:

Photoneutron yield of infinitely thick heavy metal converter as a function of the electron e n e r g y

targets

87

Fig. 3.18a

1

2

Fig. 3.18b: Photoneutron moderator (plastic material); 1 = moderator a n n u l u s , 2 = b r e m s s t r a h l u n g t a r g e t (photoneutron s o u r c e ) , 3 = sample rabbit channel f o r thermal n e u t r o n s ,

4 = d t o . for fast n e u t r o n s ,

sition for large sample volumes, 6 = electron beam tube

5 = po-

88

F i g . 3.19: Irradiation facility at the BAM Linac: explanations see text

89

3.5

Typical irradiation facility

As is explained above, a converter material of high atomic number is required. Furthermore, Moreover,

it

has

to

resist

long-time

chemical stability is obligate

chemical reaction

with any

matter

heating

and

large

to avoid subsequent

which is in close contact

radiation

doses.

decomposition with the

by

target,

e . g . cooling water.

The

irradiation

setup

used

at the

35 MeV electron

linear

accelerator

of

the

Bundesanstalt f ü r Materialprüfung in Berlin is shown in Fig.3.19. The electron beam ejected from the accelerator tube ( 8 ) through the titanium electron beam window

( 7 ) impinges on the target ( 6 ) a f t e r a distance of a few

centimeters.

The converter consists of seven tantalum discs with spaces of about one mm between so as to enable efficient cooling water flow. The power load of the converter

is about

converter

4 KVV under

routine operation

of

the accelerator.

The

total

thickness is sufficient f o r complete absorption of the 35 MeV elec-

tron beam. About 6 cm behind the converter the sample position is located. The sample and

the

reference

material are enclosed

in an aluminium

capsule and

transported by compressed air to and from the irradiation position. The axis of the capsule is perpendicular to the photon beam. The terminal of the pneumatic tube ( 4 ) is equipped with an inlet for compressed air flow injected tangentially into the tube ( 3 ) so as to cool the sample rabbit ( 2 ) .

This air flow is also

used to make the sample rabbit rotate so as to provide uniform irradiation of the sample to be analysed and the reference material ( 1 ) . The electron beam and thus the bremsstrahlung cone are adjusted with respect to the sample using the steering coils of the accelerator.

The beam position is monitored by a fluores-

cent view which is observed by a television camera.

^ζ&ΖΖΖΖΖΖΖΖΖΖΖΖΖΖ^/. r^//////////////////^ F i g . 3.20: Sample rabbit; inner diameter = 16 mm

90

At

the lower

provided

end

of

the pneumatic tube another

( 5 ) by which, after irradiation,

minal in the radiochemical laboratory.

inlet for compressed air is

the rabbit is transported to the ter-

There the irradiated matter is removed

from the rabbit and processed further as desired. The inner space of the rabbit

(see F i g . 3.20) is about 5 cm long at a diameter

of 16 mm. The rabbits as well as nearly all parts of the tube system near the converter are made of aluminium since this material is inexpensive and durable against heat, radiation and mechanical shock. Moreover, it does not accumulate cumbersome

activity

bremsstrahlung (^® m Al,

2®A1,

reactions

or

activation;

photoneutron

2 ^Mg)

have

during

all

irradiation

radioisotopes are

either

produced

reasonably

through

short-lived

or extremely long-lived ( 2 6 A 1 ) or the corresponding nuclear

very

small activation

ions

( 2< *Na,

22Na).

The

entire

sample transportation

cross

sections at the irradiation

condit-

No other material is thinkable which is comparably suitable.

system

is represented

schematically

in

Fig.

3.21. The arrival of the rabbit at the target terminal is monitored acoustically by a microphone;

this kind of monitoring has proved most reliable since the

microphone does not have to be installed in the close vicinity of the radiation source and so does not s u f f e r from heat and radiation attack. Linac T a r g e t Area

Linac Control Area

microphone

Heat Extraction Multielement Laboratory Laboratory Terminal Area Terminal Area

r

Audio Amplifier Target

Terminal

¥

Loudspeaker'

Load-unload

Fig.

3.21:

Station

Schematic representation of the pneumatic tube sample transfer system at the BAM Linac

91

Photoneutrons a r e also used for activation analysis (see 3 . 4 ) . T h e r e f o r e , sample

rabbit

pneumatic

can

be

transported

tube b r a n c h e s

(a,

b,

to d i f f e r e n t irradiation

positions

c in F i g . 3 . 2 1 ) selectable by a

the

through

distributor.

Figures 3.18a and b show the plastic material photoneutron moderator equipped with

several

irradiation

positions

so as

to enable

photoneutron

irradiations

u n d e r d i f f e r e n t conditions. In the tangential channel (4) a pneumatic tube t e r minal is installed in the "fast n e u t r o n " position (c in F i g . 3 . 2 1 ) . Here photon e u t r o n irradiations can be conducted at the maximum achievable flux density (several

10*·" cm~^ s"*) at a cadmium ratio of about u n i t y .

In the

"thermal

n e u t r o n " position (a in F i g . 3 . 2 1 ) a b e t t e r cadmium ratio is achieved (about 20) favoured by a plastic layer of about 5 cm water-equivalent between t h e photoneutron

source and

the sample position.

A third

irradiation

position

(5) i s

provided to enable large volume (maximally about 150 ml) i r r a d i a t i o n s . The positions

3 and

target;

2 in F i g . 3 . 2 1 ) a r e equipped

4 (and,

of course,

the photon irradiation

position behind

with pneumatic tube terminals.

the

Another

pneumatic t u b e d i s t r i b u t o r is provided so as to enable t r a n s f e r of the i r r a d i a ted sample to either the heat extraction laboratory where the light

elements

(C, N, O, F) exclusively a r e analysed (see 6.1) or the multielement laboratory where i n s t r u m e n t a l multi-element analyses with help of semiconductor spectromet e r s a r e performed (see 6 . 2 ) . Other

irradiation

facilities

used

for

photon

activation

ο η c_ ΟΟ Q

analysis

linear a c c e l e r a t o r s a r e described in R e f s . · 5 " " 0 " and many o t h e r s .

at

electron

92

3.6

At

Conclusion

this

point an obvious

difference between

activation

analysis

with

reactor

neutrons and methods requiring accelerator irradiation should be pointed Both particle sources are basically case of accelerators,

designed

in a medical laboratory.

for use in a physical or, However,

out.

in the

whilst neutron activa-

tion analysis is a priori included in the construction concept of a nuclear research

reactor,

activation

analysis

normally

has a comparatively

level in the daily operation

schedule of an accelerator

radiochemistry

analysis

-

activation

in

particular

-

low

(see also"*·*").

is only

priority Usually

restrictedly

al-

lowed in accelerator laboratories in terms of irradiation time and space requirement.

As f a r as the authors know, there is only one electron linac which is

used almost exclusively

for photon activation analysis,

namely the accelerator

in the Bundesanstalt f ü r Materialprüfung which was used for the present work.

This remarkable difference is not explainable by the historical development of the methods; all kinds of activation analysis have about the same date of birth (see C h . l ) .

Probably the extremely high sensitivity of thermal neutron activa-

tion analysis for a number of elements plays a certain role.

However,

in some cases photon activation analysis is much more suitable than

neutron activation methods as is shown in the following chapters.

93

4

Photon spectrometers

At the time before the invention of radiation detectors with help of which one can discriminate between different radiation energies, a separation of the components to be determined from the sample matrix was necessary during activation analysis

-

ion after

preferably radiation

carried

exposure

out after activation, does

since inactive

no harm to the analysis.

contaminat-

The activities

of

the resulting different fractions were then measured separately. Gas ionisation detectors e . g . Geiger-Müller counting tubes were used for activity counting. In the

case

of

beryllium

or

deuterium

counting tubes or secondary targets

analysis

by

photodisintegration,

neutron

(photoneutron activation f o i l s ) had to be

used as noted above. A f t e r the advent and general availability of photon spectrometers almost invariably these devices have been utilised f o r activation analysis

since

most

of

the

product

nuclides of

any

nuclear activation

process

emit typical photon spectra including gamma and specific X-radiation which can easily

be

discriminated

sample can be analysed

(see

chapter

2).

Thus,

components of

an

irradiated

without a chemical separation before or after activat-

ion. Moreover, with help of advanced spectrometry technology simultaneous analyses of several radionuclides (multi-component analyses) have become possible. Product nuclide radiation other than photons have been used in exceptional cases only,

e.g.

if the product

nuclide does not emit specific photon

However,

in these cases instead of undertaking tedious separation

energies. procedures

one would generally apply another activation method producing gamma-ray emitting

radionuclides

or another analysis

method.

Another

advantage of

photon

counting is that absorption of the radiation within the sample matrix mostly is negligible whereas in the case of beta or, even worse, alpha particle counting it

might

during

lead

to severe

misinterpretations

quantitative data evaluation.

of

the

spectra

and

miscalculation

Only in the case of v e r y soft X-radiation

used for analysis one has to be aware of significant self-absorption, monstrated in Ch.6. Due to all the mentioned advantages,

as is de-

photon spectroscopy

has become the most frequently applied activity measurement method - not only in activation analysis. In this chapter, in more detail.

the photon spectrometers are discussed

This is done because the analyst in the activation analysis la-

boratory ( t o whom this book is d e v o t e d ) generally is much more concerned with the

spectrometers

than

with

the

activating

radiation

sources.

The

analyst

usually does the entire photon spectrometry work by himself whilst the accelerator is run by another operating s t a f f .

94 Two basic principles of photon counting have been in use, namely the detection by

scintillators

semiconductor

exploiting crystals.

the

radioluminescence

By both detector types,

effect

and the detection

by

photons are converted

into

electric pulses whose heights are quasi-linearly dependent upon the energies of the absorbed photon quanta - at least in the energy region of interest in photon activation analysis (5-3000 keV; see chapters 2 and 5 ) . The pulses are then amplified,

reshaped and finally discriminated by their heights with the help of

electronic devices which are discussed separately in the following paragraphs. The resulting spectra are then processed by computer. To shortly summarise all parts of a photon spectrometer necessary for activation analysis"*·**: 1 -

Detector;

scintillation

crystal plus photomultiplier or semiconductor

cry-

stal and operating voltage supply 2 - Preamplifier, voltage or charge-sensitive,

plus power supply

3 - Linear spectroscopy amplifier; including pile-up rejector and pulse shaping unit 4 - Pulse height analyser plus data storage and data output unit which is coupled to a data dumping unit or processing device, e . g .

computer

T h e r e are various additional optional units for special procedure requirements, of course, but the minimum instrumentation needed consists of the above listed ones. In

the

following,

the

fundamental functional principles of the detectors

electronic analysis systems will not be discussed in detail. paid to the analytically

relevant

provide an aid for the analyst given task.

and

Major attention is

properties of the spectrometers in order to select

the proper system

to

suitable for the

Also the required computer software for spectral data evaluation

will be discussed only briefly.

Since the required instrumentation for radiat-

ion spectrometry and data processing is exactly the same as used in "classical" neutron activation - with a few exceptions - excellent fundamental descriptions and discussions can be found in a large number of earlier works. This also applies to the the historical development of the photon spectrometers.

Hence,

in

the following paragraphs, only a short summary of their history is given. Also, reader

the fabrication of the different kinds of detectors is not discussed; can

find

Ref's.678"680.

information

about

this

problem

in

Ref s .

.

See

the also

95 4.1

Detectors

At this stage it is of use to briefly summarise the different action of photons with matter,

kinds of inter-

especially with material used for the detection

of photons. T h r e e relevant processes for photon detection can be distinguished, namely a) the photoelectric e f f e c t , b ) the Compton scattering, c ) the pair production.

The probability of their occurance within a given element is contin-

gent upon the energy of the incident photon. Among these, effect

is of major analytical interest

whilst all others,

the

photoelectric

if occuring,

have

to

be considered as sources of interference during analysis. a) In the photoelectric process all of the energy of the incident photon is absorbed by a bound electron of a target atom reappearing as kinetic energy of this electron as it is ejected from the atom. The energy of the ejected electron will then equal the difference between the energy of the incident photon and the binding energy of the level from which the electron was ejected. Although some energy is absorbed by recoil of the target atom nucleus, this is negligible compared with the energy of the incident gamma-ray and the photoelectron.

If

interaction

the

incident

photon

energy

will take place principally

sult of this process

exceeds

the

K-shell binding

with electrons of this shell.

level,

As a re-

the atom is left with a vacancy in this shell,

resulting

in the emission of specific X - r a y quanta or Auger electrons. In the low photon energy

region

4.1.2).

It is probable that a fraction of the mentioned X - r a y s excape from the

detector.

In

the photoelectric effect

dominates,

this case signals will be detected

(see

paragraphs 4 . 1 . 1

which are representative

and for

the full incident photon energy minus the emitted X - r a y e n e r g y . The important c h a r a c t e r i s t i c of the

photoelectric effect is that monoenergetic photons which

interact by the photo process will produce monoenergetic photoelectrons within the detector volume which results,

through different subsequent processes wi-

thin the detector, in a uniform, discrete signal which then can be processed. b ) In the Compton scattering process incident photons are scattered by target atom electrons accompanied by a partial energy loss. In this process,

scatter-

ing generally occurs with electrons which can be regarded as essentially

free,

and the energy of the incident photon is distributed between the target electron and the scattered photon. This distribution does not have a fixed value but ranges within a relatively large energy interval, depending upon the incoming photon e n e r g y . T h u s , the Compton process results in a broad electron energy distribution,

and therefore,

detector pulses originating from Compton

scatter-

ing cannot be used for evaluation of photon spectra measured a f t e r activation,

96

but rather are unwanted sources of interference, as noted above. At low initial photon energies, a gamma-ray may be elastically scattered from a bound electron with the atom energy

remaining in its initial state.

change,

yet

it

plays an important

sessment of a detector. scattering

-

This process does not yield any role in the integral efficiency as-

The cross section for this process - called

coherent

must not be considered in the discussion of the total absorption

cross section since it does not leave any energy in the detector. The relationship between the energies of the incoming and the scattered photon is given by the following expressions:

(1 — cos φ)

1 +

Ee· — Ey

where Ε

Υ

Ey.

is the incident photon e n e r g y ,

Ε - the scattered photon e n e r g y , Ε Υ ^

the scattered electron e n e r g y and φ the scattering angle.

From these expres-

sions one can deduce that the Compton electron e n e r g y spectrum extends from zero e n e r g y (φ = 0) up to a maximum e n e r g y (φ = π) which is somewhat less than the incident

photon e n e r g y .

The energy distribution of the scattered

photons

varies from the initial photon energy down to a minimum value which always is less than m · c 2 /2 (= 255. 5 k e V ) . c)

Pair production;

electron/positron

if

the incoming

photon

has an energy which exceeds

pair rest mass (= 1022 k e V ) ,

the

then a production of this pair

becomes possible. This process occurs in the coulomb field in the close neighbourhood of the nucleus.

The incident

photon ray disappears and the pair is

created. Its total e n e r g y will equal the e n e r g y of the primary photon, and the kinetic

energy

of

both

particles

will

be

equal

to

their

total

energy

minus

their rest e n e r g y

(2m · c

= 1022 k e V ) . Since the positron is unstable, as it

comes

the

of

to rest

in

field

an electron,

annihilation

of

the

two

particles

occurs with the emission of two photons, in e n e r g y equal to the rest mass equivalent of the pair (2 · 511keV). Interaction by the pair process in a detector will t h e r e f o r e result in an energy loss equal to the incident photon energy minus 1022 keV, if both 511 keV annihiliation quanta escape from the detector. If

97 only one of them escapes, a signal r e p r e s e n t a t i v e f o r the total incident photon e n e r g y minus 511 keV will a p p e a r . Consequently, all in all, various kinds of interaction of photon r a y s , in e n e r gies exceeding 1022 keV, within a detector body will result in a quite complex pulse amplitude spectrum containing signals r e p r e s e n t a t i v e f o r any e n e r g y from zero up to t h e full e n e r g y of the primary photon. Moreover, it is r e n d e r e d even more complex by other e f f e c t s , e . g . , due to t h e close environment of the detector as is explained in the following p a r a g r a p h s . Other signals also a p p e a r which a r e not due to the measured sample activity at all; they originate from e x t e r n a l radiation p e n e t r a t i n g the detector

shielding

or from radioactive contaminations within the shielding material. T h e s e signals a r e called e x t e r n a l b a c k g r o u n d . This b a c k g r o u n d has to be known v e r y well to avoid misinterpretations of pulse height s p e c t r a obtained from unknown samples. 4.1.1

Scintillation d e t e c t o r s

The f i r s t of all particle detection

principles used

was scintillation

counting.

It was introduced in the beginning of this c e n t u r y . Visible light flashes were produced on a zinc sulphide screen by alpha particles. The counting was p e r formed by numbering t h e flashes d u r i n g visual inspection. Fundamental work on the theory and practice of inorganic scintillators by H o f s t a d t e r and

Mclntyre

( R e f ' s . 3 4 0 , 3 4 1 ) and by Sciver and H o f s t a d t e r 3 4 2 yielded that thallium-activated sodium iodide

single c r y s t a l s were the most suitable

scintillators for gamma

detection. See also R e f ' s . 3 4 3 " 3 6 4 , 8 9 5 . Organic

including

liquid

scintillators

are

not

discussed

in

this

book

since

t h e y a r e not used for photon s p e c t r o s c o p y . An excellent review on the development of sodium iodide d e t e c t o r s and photomultipliers is given by Adams and Dams365. Thallium activation influences the fluorescence behaviour of the N a l - c r y s t a l ; t h i s problem is not discussed f u r t h e r . The r e a d e r might r e f e r to R e f ' s . 3 5 4 , 366-378, 516 f o r m o r e i n f o r m a t i o n .

A schematic Light

representation

of

a

scintillation

detector

is

given

in

Fig.4.1.

flashes a r e produced via secondary electrons from photoelectric e f f e c t ,

Compton s c a t t e r i n g or interactions due to pair production if X - r a y s or gamma photons a r e a b s o r b e d within the c r y s t a l (see a b o v e ) . These f l a s h e s produce

98 produce photoelectrons in a photocathode. The electrons are directed to a photomultiplier which is connected to an operating voltage of usually about 1 kV. By secondary electron emission, the incident electron pulses whose heights show a linear dependency upon the energy of the incoming photons are amplified and then can be processed in the following electronic system of the spectrometer. Nowadays,

a fairly large list of scintillation phosphors is available with va-

rious material parameters,

depending upon the individual requirements of the

u s e r . Detailed decriptions of the different phosphors are given in the recommended literature cited below. At this point a summary of some important properties is presented for the phosphors which are widely in use nowadays 3 ^ 9 , one

. The characteristic data of a scintillation detector are dependent on many parameters of which some are given in Table 4-1.

T a b . 4 - 1 : Scintillation phosphor characteristics

Material

Wavelength

Nal(Tl)

(nm) 1 410

yes

100

CsI(Na)

420

1.84

4.51

yes

85

CsI(Tl)

565

1.80

4.51

yes

45

CsF

390

1.48

4.11

no

5

470-485

1.96

4.08

yes

35

CaF2(Eu)

435

1.44

3.19

no

50

Bi4Ge3012

480

2.15

7.13

no

8

BaF2

325

1.49

4.88

no

10

TlClCBe, I)

465

2.4

7.00

no

2.5

KI(Tl)

426

1.71

3.13

yes

24

CaW0 4

430

1.93

6.062

no

50

CdVV04

540

2.3

7.90

no

65

Plastic

350-450

varies

6

LiI(Eu)4

Index of

Density

refract.2 1.85

(g/7 lity amplifiers . The pile-up rejection works t h u s : when an incoming pulse has reached its maximum, s u b s e q u e n t

pulses are automatically inhibited

the output pulse has recovered to the baseline.

until

This is achieved by a v e r y

complex electronic circuit which is not discussed here (the r e a d e r might r e f e r to R e f ' s . 5 4 5 , 5 5 8 - 5 8 0 ) ^

the

moPe

s

i n c e recently t h e i r basic principles have been

r e d i s c u s s e d critically and promising new systems of pulse processing - especially the handling of high count r a t e s - have been suggested 5 ® 1 " 5 *'®. To summarise,

linear spectroscopy amplifiers a r e to convert incoming

from the preamplifier into,

ideally G a u s s i a n - s h a p e d ,

pulses

n o i s e - f r e e pulses,

whose

h e i g h t s a r e proportional to the photon e n e r g y incident to the d e t e c t o r .

These

pulses should arise on a stable, a d j u s t a b l e baseline. The amplifier should be

143

able to process a count-rate range from zero to at least 10 5 /sec without any kind of pulse quality In

the

photon

degradation338'396·420'421·587·588.

activation

analysis

context,

one

other

spectroscopy

amplifier

version among the large number of available units is worth mentioning, the biased

amplifier.

With

help of this,

parts of a pulse amplitude

namely

spectrum

may be expanded to a smaller scale. Usually the desired portion can be selected arbitrarily

by

expanding

of spectral regions of interest can be achieved more efficiently by

setting

continuous bias level adjustment. However,

a digital offset in the

multichannel analyser.

in many cases,

This is explained

the fur-

ther in the following paragraph.

Further recommended literature about spectroscopy amplifiers can be found in Ref's.589'595. 4.2.2

Pulse height measurement

F i g . 4.30: Function principle of an integral discriminator; pulses, whose maxima are located beneath the threshold level ( a ) are discarded

144

Since, as noted above, pulse heights of solid state d e t e c t o r s a r e proportional to the incident photon ray energies a pulse-height discriminator is r e q u i r e d to keep

track

namely

of the

spectral

the integral

distribution

discriminator,

of the radiation.

is due

to the

basic

The idea

simplest of

one,

Schmitt"'®®,

whose diagram includes a threshold which rejects all electric pulses lower than an a d j u s t a b l e level

(see F i g . 4 . 3 0 ) .

T h u s it was possible t o "cut" off lower

p a r t s of a radiation spectrum sequentially. Many circuits of integral discriminators

have been

Parsons

599

developed

, Moody et a l .

519

since then

, Francis

(Elmore 5 ® 7 ,

et a l .

600

Westcott and

Hanna598,

).

The differential pulse height discriminator - also called single channel analys e r - was developed almost simultaneously.

Different working principles were

used to t r i g g e r t h e data output device by pulses whose heights fall within an a d j u s t a b l e "window" between two pulse height levels (see F i g . 4 . 3 1 ) ; mostly an anti-coincidence mechanism was u s e d . The f i r s t one was r e p o r t e d by R o b e r t s 6 0 1 . Later but as well fundamental work was performed by Glenn®"'*'® 03 , Watkins®"^, Fairstein522-526,

Gatti and

Piva605.

Special devices including linear amplifi-

e r s and window discriminator with high window-width and level stabilities were developed by Gatti®"® and Colombo et al.®" 7 . Using a single channel a n a l y s e r all signals outside the window are d i s c a r d e d . This wastefulness is only a c c e p t able if the radiation source is strong and long-lived enough to o f f e r a satisf a c t o r y high count rate within t h e window area t h r o u g h o u t t h e i n t e g r a l spectrum counting period. The extension of the single channel a n a l y s e r towards an i n t e grated

device

with

several

windows

with

adjacent

pulse

height

levels

was

s t r a i g h t f o r w a r d . By this multichannel a n a l y s e r a large p a r t of t h e pulse hight spectrum

(and t h e r e b y of the radiation spectrum to be analysed) i s processed

simultaneously. This is of special a d v a n t a g e and f r e q u e n t l y unalterably necess a r y in the case of s h o r t - l i v e d activity measurements. The

first

multidiscriminator analyser systems were r e p o r t e d in t h e late 1940s

(Freundlich et a l . 6 0 8 , there

were

earlier

(Wilkinson610).

Westcott and H a n n a 5 9 8 ,

developments

which

have

K e l l y 6 0 9 ) , although not

been

published

apparently explicit ely

The largest multidiscriminator analyser contained 120 channels

( C h a s e 5 2 1 ) . Multidiscriminator a n a l y s e r s s u f f e r e d from f r e q u e n t breakdowns and window width and level instabilities,

whereas o t h e r pulse height a n a l y s e r

sy-

stems, e . g . g r e y - w e d g e a n a l y s e r s and photographic systems (Maeder and Medicus ( R e f ' s . ® 1 1 , 6 1 2 , Bernstein et al.® 1 3 ) h a d insufficient resolution. Both problems were overcome and all o t h e r systems became obsolete by the i n vention of t h e Wilkinson type p u l s e - h e i g h t - t o - t i m e analog to digital c o n v e r t e r

145 (ADC; see below, 4 . 2 . 2 . 2 ) (Wilkinson 6 1 0 ). Fundamental work on ADC systems of various kinds was performed by Fulbright and M c C a r t h y 6 1 4 , G a t t i 6 0 6 , Byington and J o n s t o n e 6 1 5 , Schumann and McMahon 6 1 6 , C h a s e 6 1 8 , Colombo et a l . 6 0 7 , Kochand J o n s t o n 6 1 9 , Russell and L e F e v r e 6 2 0 , McMahon and Gosolowitch 6 1 7 , S c h u l z 6 2 1 . See also R e f ' s . 6 2 2 ' 6 2 ^ . A s t o r a g e memory of any kind is r e q u i r e d to keep track of t h e acquired data and to make them processable. The f i r s t multichannel a n a l y s e r with a computer memory was developed by Hutchinson and S c a r r o t 6 2 6 ; see also Franck

et a l . 6 2 7 .

McKibben

624

Different storage systems were r e p o r t e d

and Wells and P a g e

625

; see a l s o

628

by Gallagher and

. Wells and Page were the first

to use a magnetic core memory to store the accumulated d a t a . With help of these mentioned improvements special spectrometry techniques like anti-Compton c o u n t ing and o t h e r s became possible (Michaelis and S c h m i d t 5 0 1 ' 6 2 9 ) and the time of the first availability of improved high resolution photon spectrometers can be considered

the date of birth of instrumental multielement activation

A review of pulse discriminating devices is given in R e f .

675

analysis.

.

A counting of the pulses from a spectroscopy amplifier could be accomplished with help of a simple digital scaler;

in this case not even a measure of the

integral radiation activity of the counted sample could be o b t a i n e d . It is not only the inability of the pulse counter to discriminate the d i f f e r e n t energies within a photon unalterable.

spectrum which makes the application of pulse discriminators

Both

pulses due to electronic noise and

signals

due to

various

interaction e f f e c t s of the radiation in t h e detector ( e . g . Compton signals, see p a r a g r a p h s 4 . 1 . 3 f f ) cannot be recognised as such with help of only pulse c o u n t ing devices. 4.2.2.1

Single channel a n a l y s e r s

As touched on a b o v e , the integral discriminator is the simplest among all pulse height a n a l y s e r s .

Since only a lower threshold can be set by an integral dis-

criminator ( F i g . 4 . 3 0 ) , an integral of the spectrum can be measured only. Differential spectrum analyses can be performed by t h e use of single channel a n a l y s e r s , also called differential discriminators(see F i g . 4 . 3 1 ) . A whole spectrum can be measured by scanning a constant window over the entire pulse height distribution.

Pure

differential discriminators

a r e o f f e r e d by several

manufactu-

r e r s , but in analytical photon spectroscopy units a r e in use almost exclusively which combine a linear amplifier and a discriminator. These devices a r e called "amplifier/single

channel

analyser"

mostly used for scintillation

or

window amplifier.

spectroscopy

Nowadays

they

are

since usually only one or very few

photon e n e r g y lines a r e processed d u r i n g activation analysis using scintillat-

146

tion counting.

In photon activation analysis the most prominent example is the

analysis of the light elements ( C , N , 0 , F )

where only the 511 keV annihilation

line is processed after chemical separation of the mentioned elements from the matrix

(see chapter

6.1).

In this case,

the window is permanently

positioned

to measure the 511 keV line. Instead, in higher resolution photon specroscopy, primarily multicomponent spectra are processed, and the use of a single channel analyser is not practical.

Fig.

4.31:

Function

principle of a differential discriminator;

only those

puls-

es whose maxima are located between the window levels (a and b ) are registered

4.2.2.2

Multichannel analysers

T o summarise: all multichannel analysers contain the following elements: -

A quantising and digitising device

(analog to digital c o n v e r t e r )

that assoc-

iates each incoming signal with a specific amplitude channel,

- A data storage device (memory) which keeps track of the number of signals which fall in each of the amplitude channels,

147

- A display service (cathode ray tube) which allows immediate visual inspection of the collected data, -

A data output

facility of any kind which allows either data storage on any

carrier or immediate data processing by computer. Modern multichannel analysers with help of microprocessors and more and more expanding associated available software are extended to entire spectrum analysing,

processing and evaluating systems, with help of which, theoretically, the

data processing work could be performed without external computers i n v o l v e d . However as yet, these systems are not flexible enough to meet all the different requirements of an analytical laboratory performing various analysis of d i f f e r ent material kinds and classes and thereby v e r y different analysis procedures. Hence, f r e e l y programmable,

flexible computers are still necessary in these ca-

ses. A n y w a y , the "pretreatment" of the spectral data in microprocessor-equipped multichannel analysers can be v e r y useful f o r the reduction of the data passed on to the computer, saving both computing time and memory space as already noted.

In the following, the different operating units of a modern multichannel analyser,

including the most common data processing options will be discussed.

No

d i f f e r e n c e is made between standard and optional units; this is v e r y much due to the individual policy of the manufacturer.

Inputs Besides the input

for the analog

pulse from the linear spectroscopy

output various other signal inputs are available,

amplifier

namely:

a) An input intended for sequential multichannel scaling. Mostly logic rectangular pulses are used, but usually any other pulse shape exceeding a certain height and duration is accepted. b)

A gate input is provided

for the case that any kind of data

acquisition,

processing or output is to be gated by logic pulse. c)

Several remote control inputs are provided f o r remote initialising and terminating

of

various

operations

by

multichannel scaling sweep start, data readout

etc..

logic

pulse,

e.g.

data

collect

channel advance and sweep stop

trigger, trigger,

148

The execution of these functions might also be initialised by computer using a connection through a suitable data input/output (I/O) interface. This is the next item to be explained. I/O - units I/O units are combined input/output facilities. For fast and convenient data processing several I/O units are provided,

equipped with suitable electronic

interfaces to provide data formats acceptable by any peripheral unit. a) On-line computer I/O unit; with help of this data may be transferred to the computer where they are processed immediately or stored intermediately on a secondary data carrier. Conversely, the multichannel analyser may be controlled automatically by computer with help of adequate software using the mentioned I/O unit. b ) I/O unit for terminals; cathode ray tube terminals or printers may be used for data input/output and multichannel analyser remote control. c)

I/O unit for disc recorder; either solid or flexible discs are used mostly for immediate fast data dumping but may also serve for the above described correspondence with the multichannel analyser. This is also true for

d ) I/O for paper tape and magnetic tape recording and reading devices. Data outputs Most of the data outputs operate as I/O units mentioned above. Besides the internal cathode ray tube display which might also be considered as a data output device, following outputs are usually provided: a) Single channel analyser logic pulse output; the pulse rate might be acquired from any region of interest of the spectrum, selectable through a built-in single channel analyser. b ) X/Y and graphic plotter output for spectrum processing and documentation c ) Lane printer output; partitions.

usually this is used for fast digital dump of memory

149

Processor The

processor

is

many tasks, e . g .

the

"heart"

of

the

multichannel analyser.

It

has to fulfill

direct the signals from the analog-to-digital converter output

into the proper memory location;

enact the commands from the controls either

initialised manually by the user or remotely by computer, and many more. The most important operation unit within the processor is the memory. It is, as noted above is divided into channels, each representative for a certain range of incident pulse heights;

this means that the resolution of the multichannel ana-

lyser is linearly dependent upon the number of channels available in the memory.However, (conversion

this

gain)

resolution

of

the

capability

analog-to-digital

is

limited

converter

by

the

as

operating

is explained

range below.

A n y w a y , channel blocks exceeding this maximum are useful, too; they might serve as intermediate storage memory for visual inspection during undelayed collection of the next spectrum or internal data processing which will be discussed in detail later on. ter,

T o provide optimal e n e r g y resolution of the entire

a photopeak in a spectrum should contain at least

due to the

poor intrinsic

resolution

capability

five

spectrome-

channels.

of a scintillation

Hence,

crystal,

on-

ly camparably few channels are necessary f o r Nal-spectrometry, typically s e v e ral hundreds.

For high-resolution spectra,

however,

if they cover an energy

range from say 100 to 2000 keV, at least 4000 channels would be required

to

provide optimum e n e r g y resolution. Nowadays, by virtue of semiconductor storage units available,

memory sizes up to 64000 channels are optionally available in

multichannel analysers.

Usually,

1024 is the mimimum total memory size which

can be extended in binary increments i . e .

2048,4096, e t c . . This is due to the

binary operations logic of the multichannel analyser memory (the operation mode is the same as that of computer memories; tecture,

all in all,

due to its logic archi-

a modern multichannel analyser may be regarded as a computer with a

f i x e d basic program,

which usually is called the " f i r m w a r e " ) . The total count

capacity is mostly 2 ^ - 1 or 1048575 counts per channel. The maximum standard o f f e r e d , as f a r as the authors know, is 2 ^ - 1 or 16777215 counts per channel. According to the desired number of channels per entire spectrum, partitions of the total memory can be addressed from the analog-to-digital converter or other sources,

normally starting with 2® o r 256. In the case of pulse height analy-

sing, in the first channels (0 and 1) counting time data are stored and cannot be addressed from any other source but the internal clock. The memory can be cleared

entirely

or in partitions

selectable manually at the panel control

(or,

as noted above, remotely by any remote control unit, e . g . computer p r o g r a m ) . In many modern multichannel analyser models data clearance and many other operations, especially concerning the memory contents, require the o p e r a t o r ' s confix—

150

mation to avoid accidental loss of data. Groups of adjacent channels may be marked as regions of special interest to facilitate later spectrum

processing

(see below, analysis options).

The

contents

of groups of channels - usually starting with 256 as the smallest block and its binary increments - may be transferred into other locations within the memory. Unlike in magnetic core memories which had been used earlier, semiconductor memory data must be protected against failure of the main power supply. This is accomplished by an internal intermediate battery power unit which usually does not enable any multichannel analyser operation but is only intended to protect the memory contents.

Analog to digital converter As

noted above,

ters

almost

Wilkinson-type

exclusively

principles in use, due

used

by

photon

but for spectroscopy

to its excellent linearity.

is digitised

pulse-height-to-time

for

charging

There

conver-

are also

other

the Wilkinson-type device is superior

The operation

a capacitor

analog-to-digital

spectroscopy.

principle is as follows:

A pulse

to the amplitude of the input and

then

discharging the capacitor at a constant discharge rate. During the discharge a crystal timer-controlled

pulse sequence is counted in a register until the ca-

pacitor charge is decayed to zero. The number in the register then is proportional to the input signal height and corresponds to a specific channel

whose

contents is increased by one unit.

Important

factors of

the analog-to-digital

converter

are the conversion

gain,

the dead time and the linearity. The conversion gain, given in channels per input voltage range, or just channels,

refers

to

the

slope

of

the

analog

to

digital

converter

capacitor

dis-

charge function described above; it determines the number of channels in the memory which are addressed

(or t r i g g e r e d ) by the analog to digital c o n v e r t e r , Q

again usually starting with 2

normally selectable in binary increments up to a

maximum of 2^·^ (16384). The quartz timer frequencies are 50-400 MHz. The dead time r e f e r s to the time the analog-to-digital converter is busy while processing a pulse and cannot accept another. The dead time can be accounted f o r since it can be exactly calculated. Compensation f o r dead time is accomplished by data acquisition for "live time" periods,

rather than "clock" or " t r u e "

time. The live time is obtained by gating off the internal clock with the dead

151

time. However, t h e dead time correction d u r i n g operation of multichannel a n a l y s e r s is somewhat problematic; see R e f ' s .

.

Normally, t h e timing mode of data acquisition may be selected b y the o p e r a t o r , and usually both counting period information a r e available in t h e memory (normally in channels 0 and 1 a s touched on a b o v e ) . It is important to note t h a t t h e contribution of the electronic system to the total dead time of the spectromet e r can be compensated, this dead

but not the dead time of the detector c r y s t a l itself;

time is not explicitely

determinable.

Therefore,

in o r d e r to avoid

measurement e r r o r s in high-precision measurements, it is of use not to exceed a certain i n t e g r a l count r a t e . The linearity of the analog-to-digital c o n v e r t e r is given in terms of d i f f e r ential and i n t e g r a l nonlinearity. Integral nonlinearity may be described as t h e deviation energy

from a linear function of pulse height

versus

channel number,

respectively.

variation of the width of the single channels. i n t e g r a l nonlinearity ty.

Usually

v e r s u s channel number,

or

Differential nonlinearity is t h e Typical values a r e 0.025% for

(1 channel per 4096) and 1% for differential nonlineari-

in activation

analysis

application

of

multichannel

analysers,

li-

n e a r calibration f u n c t i o n s a r e sufficient f o r e n e r g y calibration. A digital offset can be set by the o p e r a t o r .

This is the capability of

sub-

t r a c t i n g a selectable channel number (usually in increments of 1 in modern multichannel a n a l y s e r s ) from the number of converted channels (see above, c o n v e r s ion gain) b e f o r e the memory is a c c e s s e d . biased amplifier (see a b o v e ) ,

This is equivalent to the use of a

but has the a d v a n t a g e of being digital and t h u s

more e x a c t . It is mostly used to cut off lower e n e r g y r a n g e s and expand h i g h e r ones a c r o s s t h e full memory size. An offset can also be set by s h i f t i n g the baseline output level of the s p e c t r o scopy amplifier (see 4 . 2 . 1 . 2 ) but this is recommended in exceptional cases only since both the amplifier and the multichannel a n a l y s e r operate optimally at a p proximately zero pulse baseline voltage. For more information about analog-to-digital c o n v e r t e r s R e f ' s . recommended.

634-642

are

152

Mixer/router Mixer/router inputs for data acquisition from multiple sources, typically up to 8, can be used for both pulse height analysing and multichannel scaling; some multichannel analyser models allow both kinds of pulse processing simultaneously.

This unit, on the one hand, is extremely useful in the case that it pro-

vides a pseudo-multiple analog-to-digital converter

pulse processing,

i.e.

all

operation functions can be directed and executed independently in all selected partitions of the analog-to-digital converter;

on the other hand, in the case

of excessive integral pulse frequency incident to all inputs spectra might be distorted since the dead times of the single partitions of the analog-to-digital converter are added up. In high-quality multichannel analysers the optional use of more than one analog-to-digital converter is provided; these usually are available as NIM-module plug-ins. Multichannel analysers can be used not only for pulse height analysing but also for multichannel scaling as shortly touched on above in the paragraph on the inputs. In this case the channels are activated or opened to the signal input (usually it is a separate input) sequentially at selectable dwell times. During the dwell time (selectable from microseconds to hours) incoming pulses are collected in the activated channel without regarding their heights as they exceed a predetermined

threshold height.

This application is particularly

useful for

analysis of decay functions for half-life determinations. In early multichannel analysers only a data acquisition with clock timing, optionally

plus dead time correction,

was possible.

In modern,

microprocessor-

equipped ones the data acquisition can be terminated by various other criteria as well, namely number of counts in any specific channel, overflow of any channel oontents,

integral in a specified region of the memory,

net area or its

statistical error of a specific peak and other criteria. Internal display Cathode-ray tube display units are used in most multichannel analysers.

CRT

screens in modern units are considerably large, typically about 30 cm in diagonal, to accomodate the operator's data inspection, operation setting and control. The display should be non-flickering and have high contrast. Frequently, different groups of data can be displayed in different colours to enhance the contrast of the displayed image. The primary task of the display is to allow immediate visual inspection of the data which have been collected and stored in

153

the memory, but it is not its only function. The display should enable the operator to keep track of all analyser functions which have been initialised also of those which are in operation and finally of those which are intended to be initialised,

i.e.

functions

whose

execution

is

initialised

by

an

internal

or

remote computing device within a sequential operation program. Usually a lot of information can be displayed on the CRT. In order not to overload the screen with information, groups or logical blocks of data are displayed on the CRT upon the operator's request. The different features of the display in modern multichannel analysers are summarised in the following. The memory contents or parts of it can be displayed, usually starting with 256 channels covering the horizontal full scale, increasing in binary increments up to a displayable maximum, typically

or 16384 channels. Normally also small-

er channel blocks may be expanded separately over the full horizontal scale. Single channels or blocks of adjacent channels may be identified and marked with single or dual markers. Different parts of the memory may be displayed simultaneously to allow immediate comparison, e . g . of two gamma-ray spectra. In some analysers it is possible to scan a window which covers a selectably sized part of the memory contents over the whole range to allow detailed inspection of the entire spectrum by displaying the screened part separately,

expanded

over the entire horizontal scale. The vertical scale display mode may be selected linear or logarithmic, in some models also at a square root scale.

In the case of linear display mode, the

vertical full scale range may be selected in different steps up to the maximum capacity of a channel, as mentioned above usually being 2^" counts. Following further information should be displayed, either permanently or upon the operator's request: preset counting time or other data acquisition limitations,

actual horizontal and vertical full scale range,

time and date,

actual

ADC dead time, input pulse frequency, number and contents of the cursor-located channel, in the case of dual markers integral channel contents between the markers. In some analyser models extra memory space is provided for any individual identification code or name of the data set; this code can be entered into the memory from any outer data I/O-device (see above, data inputs and outputs), and is then displayed on the CRT to allow immediate data set identification. Finally, all operations are traced by the display, mostly in a dialog mode, including command checks, warnings and comments, e . g . request for confirmation, to avoid missettings and accidental damage of data, as mentioned in the above

154 paragraph on the multichannel analyser processor. More about information to be displayed on the CRT is mentioned in the following paragraphs about the data analysis and computing units of the analyser. Analysis options The analysis software other than the above described components mostly is supplied optionally upon the users request since it serves very special demands. For instance, a nuclide library may be helpful if the spectrometer is primarily used

for analysis

of

radioactive

wastes or effluents or other

contamination

whereas it is of no use for those who mainly perform multiscaling measurements. Therefore, the user should be able to select the offered software options according to his special requirements. Some of these analysis options are not urgently

necessary

if

-

as is usual in activation

analysis -

the

multichannel

analyser is coupled on-line to a computer, but they might be helpful in reducing the data to a conveniently processible minimum and thus help to save computer memory space and computing time. Following analysis options are usually offered: - Internal energy calibration function computation - Peak centroid location - Net peak area calculation - Peak search - Spectrum smoothing - Spectrum stripping - Spectrum normalisation and ratio computation - Isotope identification by internal isotope library - Spectrometer efficiency calibration and quantitative activity analysis and others. Additionally

frequently

learn/execute

facilities

are

available

to

allow

se-

quential operation step execution, e . g . including sample changing, data processing or transfer e t c . . As yet,

due to the limited size of a multichannel analyser software capacity,

some of these analysis routines operate with limitations, e . g . usually no peak multiplet unfolding is possible,

and it is not possible to perform a complete

activation analysis evaluation. Therefore, as already stated, an external com-

155

puter is still a must in multielement activation analysis.

However,

regarding

the advances in nuclear electronics, this might change in the near future. 4.2.2.3

Miscellaneous options

In the following,

several electronic devices are briefly described which are

not necessarily imperative for a photon spectrometer but have proved useful for photon activation analysis work. - Coincidence unit; especially in the case of the light element analysis, as is explained in detail in chapter 6.1, a pulse coincidence unit may enhance both the sensitivity of the method and the accuracy of the results. Pulses originating from two sources (usually Nal crystals) are fed into the coincidence unit. All pulses falling in non-simultaneously are then gated off and discarded. In the case of coincidence, a signal is passed on to a following counting or analysing device. -

Spectrum

stabiliser;

this

unit

gain shifts due to any instability

fulfills serveral

tasks.

It compensates

source within the spectrometer

for

(detector,

high voltage supply, preamplifier, spectroscopy amplifier); it also compensates for baseline level excessively

shift in the spectroscopy

high count rates.

amplifier which often occurs at

To summarise, the spectrum stabiliser ensures

drift-free data acquisition over quasi-unlimited counting time. - Reference pulser; due to the complexity of a photon spectrometer it is of use to provide a monitoring device which tests the proper operation of the spectromemter and investigates malfunctions. With help of a high-precision pulser, quasi-"ideal" pulses can be fed into any of the electronic specrometry devices to simulate ideal input conditions in the electronic system. A verification or, if necessary, an adjustment of the corresponding output signal can be made with use of known input which is free of detector limitations. Thus, the reference pulser can be used for stability or linearity checks on the equipment, to determine contamination by electronic noise, to calibrate and monitor the pulse height analysis system and finally, to check the proper operation of the whole electronic part of the spectrometer. Moreover, the dead time of the electronic part of the spectrometer can be accounted for by feeding the constant reference pulser frequency into the appropriate preamplifier input and measuring the area of the corresponding pulser peak.

156

4.3

The spectrometers used for the present work

In this paragraph, the photon spectrometers are described which have been used for the present work,

especially for the determination of the data given in

Ch.5. Fig.4.8 shows the shielding configuration of the detector, the detail figure 4.32 represents the detector head plus sample positioner.

Fig. 4.32: Sample position setup used in the present work; 1 = detector head, 2 = plastic cylinder,

3 = sample holder,

4 = inlet

for

test-tube

sample holder, 5 = lead- or iron shielding

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a j CO

ο

«

«

CU

rH a j

Μ a

rg a

W a

χ

CO

CO

rp

CD.

χ

CO

CL, Ν a

χ

χ

CO

CO

L

CO ο

ο

Ο a A!

a J

a

α,

ο

a

qp

X

J«2

Λί

ϊ Λ

Ο

α.

α.

en

m

Χ

Χ

3

Qi

CD

ϊ£>

CO

CO

Ci

irt

•υ

Oi

in

00 τ—(

CO Ο

c 'So

TH

1-H

0)

(V

02

QS

ί-Η e J

i-H e J

φ

CO 00 i-H

ω Ο

CO

CO

00 i-H

r—

φ 05

α

0)

CS

03

»-H 8 J

i-H CO. J

61.5

(7)

9.5 h

Hg-195

Hg-196

5.4 E-3

63.1

(44)

30.7 d

Yb-169

Yb-170

1.3 E-2

64.0

(20)

15.15 h

Eu-157

Gd-158

2.4 E-3

64.0

(11)

41.2 d

Ag-105

Ag-107,, Cd-106

2.9 E-3

64.8

(1)

6.75 d

U-237

U-238

?

65.5

(2)

9.59 h

Dy-155

Dy-156

3 . 0 E-4

65.7

(1)

64 h

Re-182

Re-185, Os-184

2 . 0 E-5

66.9

(13)

13 d

Cs-136

Ba-137

1 . 4 E-4

67.0

(72)

7.1 h

Se-73

Se-74

1.1 E - l

67.1

(7)

142 d

Lu-174m

Lu-175

6 . 0 E-4

67.7

(41)

115 d

Tal82

W-183, Ta-181

1.0 E-3

67.8

(13)

64 h

Re-182

Re-185, Os-184

2.6 E-4

68.7

(0.2)

4.8 h

Ga-73

Ge-74

1.7 E-3

68.9

(0.06)

40.2 h

La-140

La-139

7.2 E-6

69.7

(2)

241.6 d

Gd-153

Gd-154

7 . 0 E-5

69.7

(5)

46.75 h

Sm-153

Sm-154

2.2 E - l

72.5

(11)

23.8 h

W-187

W-186

1.2 E-2

73.8

(0.5)

3.1 h

Ho-167

Er-168

6.0 E-4

74.4

(0.07)

13.03 h

Os-191m

Os-192

?

74.6

(10)

6.9 d

Tb-161

Dy-162

1.0 E-3

76.2

(0.5)

3.1 h

Er-161

Er-162

1 . 1 E-3

76.5

(5)

3.31 a

Lu-174

Lu-175

3 . 1 E-4

77.4

(17)

20 h

Pt-197

Pt-198

3.7 E - l

77.4

(19)

64.1 h

Hg-197

Hg-108

2.6 E-2

77.5

(3)

2.5 h

Ho-161

Er-162

1 . 1 E-3

78.6

(8)

1.37 a

Lu-173

Lu-175

5.3 E-4

78.7

(11)

6.7 d

Lu-17:

Lu-175

1 . 1 E-3

79.3

(2)

3.1 h

Ho-167

Er-168

2 . 4 E-3

217 T a b . 5 - 4 , continued E.keV

Τ

Nuclide

Target Nuclide

Ν * I

18.56 h

Gd-159

Gd-160

1.8 E-3

(11)

150 a

Tb-158

Tb-159

2 . 4 E-5

(11)

93.1 d

Tm-168

Tm-169

1.8 E-2

80.6

(6)

26.7 h

ho-166

Ho-165, Er-167

2.7 E-2

(1%)

79.5

(0.04)

79.6 79.8 80.6

(11)

7.7 h

Tm-166

Tm-169 , Yb-168

3.9 E-4

80.7

(9)

68 m

Ho-162m

Ho-165

?

82.2

(2)

11 h

Pt-189

Pt-190

2.0 E-3

82.3

(15)

56.7 h

Yb-166

Yb-168

3.2 E-4

82.5

(0.03)

15.4 d

Os-191

Os-192

2.3 E-7

83.0

(0.6)

8.1 h

Dy-157

Dy-158

2 . 1 E-4

83.5

(2)

3.1 h

Ho-167

Er-168

2.0 E-3

84.3

(3)

128.6 d

Tm-170

Tm-169 , Yb-171

4 . 5 E-3

84.7

(0.9)

71 d

Re-183

Re-185, Os-184

2.6 E-4

86.5

(29)

5.32 d

Tb-155

Dy-156

6 . 1 E-4

86.8

(13)

72.1 d

Tb-160

T b - 1 5 9 , , Dy-161

5.6 E-4

87.5

(0.4)

3.1 h

Er-161

Er-162

8 . 4 E-4

87.6

(1)

56 h

Br-77

Br-79

2.2 E-3

88.0

(0.3)

38.8 h

As-77

Se-78

2.5 E-4

88.0

(4)

(39.6 s )

Ag-109m

Pd-110

?

88.3

(9)

3.68 h

Lu-176ml

Lu-175, Hf-177

3.5 E - l

89.0

(9)

15.2 d

Eu-156

Gd-157

8.7 E-5

89.2

(18)

5.35 d

Tb-156

Tb-159

2 . 1 E-4

89.4

(2)

70 d

Hf-175

Hf-176

6.5 E-4

218

5.3.4

High e n e r g y ( e n e r g y g r e a t e r than 90 keV) gamma-rays

In table 5-5, all gamma-ray energies from 90 t o 3000 keV which have been d e t e c ted a f t e r b r e m s s t r a h l u n g irradiation,

a r e listed following the same format as

in the preceding table. Because of poorer e n e r g y resolution capability of a coaxial l a r g e volume Ge-detector compared with a planar low e n e r g y photon diode, the e n e r g y v a l u e s a r e given in i n t e g e r k e V - u n i t s in this t a b l e .

219

T a b . 5-5 E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

90

(85)

5.76 d

Sb-120m

Sb-121, Te-122

6.4 E-2

90

(72)

96 m

Eu-152ml

Eu-153

2.7

90

(1.0)

9.56 h

Dy-155

Dy-156

1.5 E-4

91

(26)

42 m

Cr-49

Cr-50, Fe-54

4.8 E - l

91

(27)

10.98 d

Nd-147

Nd-148

1.4 E-2

91

(3)

29 m

Ho-164

Ho-165

1.0

92

(0.8)

11.5 d

Ba-131

Ba-132

1.2 E-5

93

(17)

61.9 h

Cu-67

Zn-68, Ga-71

3.0 E-2

93

(38)

78.3 h

Ga-67

Ga-69

7.2 E-2

93

(5)

44.3 s

Ag-107m

Ag-109,, Cd-108

1.5

93

(5)

6.5 h

Cd-107

Cd-108

5 Ε·-3

93

(0.1)

19.5 m

Tb-163

Dy-164

3.6 E-4

93

(7)

28.4 m

Lu-178

Hf-179

2.3 E-3

93

(19)

22.7 m

Lu-178m

Hf-179

w 4.6 E-3

93

(7)

5.5 h

Hf-180m

Ta-181, Hf-180

93

(6)

9.25 m

Ta-178

Ta-180

1.4 E-2

93

(17)

2.2 h

Ta-178m

Ta-180

7.5 E - l

93

(4)

8.1 h

Ta-180m

Ta-181

1.8

94

(0.5)

33 h

Sr-83

Sr-84

1.4 E-4

94

(2)

30.7 d

Yb-169

Yb-170

5.6 E-4

94

(5)

11 h

Pt-189

Pt-190

4.9 E-3

95

(4)

2.35 h

Dy-165

Dy-164

3.8 E-2

96

(10)

3.9 m

Se-79m

Se-80

5.9 E - l

96

(7)

18.7 m

Eu-159

Gd-160

2.9 E-2

96

(9)

8.2 m

As-79

Se-80

1.2 E - l

97

(3)

120 d

Se-75

Se-76

3.9 E-4

97

(2)

1.73 h

Nd-149

Nd-150

5.1 E-2

97

(0.7)

46.75 h

Sm-153

Sm-154

3.1 E-2

97

(3)

2.8 d

Pt-191

Pt-192

1.6 E-3

97

(18)

6.75 d

U-237

U-238

?

97

(27)

241.6 d

Gd-153

Gd-154

9.0 E-4

97

(3)

4.4 m

Rh-104m

Rh-103, Pd-105

2.8 E - l

98

(23)

2.6 m

Nb-99

Mo-100

4.4 E-2

99

(5)

150 a

Tb-158

Tb-159

1.1 E-5

99

(4)

93.1 d

Tm-168

Tm-169

6.8 E-3

99

(3)

71 d

Re-183

Re-185, Os-184

8.7 E-4

99

(9)

2.5 h

Ir-195

Pt-196

3.4 E-3

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

99

(11)

183 d

Au-195

Au-197 , Hg-196

7 . 9 E-4

100

(14)

115 d

Ta-182

W-183, T a - 1 8 1

3 . 4 E-4

100

(15)

64 h

Re-182

Re-185, , Os-184

3 . 0 E-4

100

(14)

13 h

Re-182m

Re-185

100

(?)

12.1 d

Ir-190

Ir-191

w 9

101

(3)

1.37 a

Lu-173

Lu-175, , H£-174

2 . 0 E-4

101

(27)

6.75 d

U-237

U-238

?

102

(0.6)

8.1 h

Ta-180m

Ta-181

2.7 E - l

103

(8)

57.3 m

Se-81m

Se-82

2 . 0 E-2

103

(28)

46.75 h

Sm-153

Sm-154

1.2

103

(19)

241.6 d

Gd-153

Gd-154

6.7 E-4

103

(0.1)

6.9 d

Tb-161

Dy-162

9 . 7 E-6

103

(3)

2.5 h

Ho-161

Er-162

1 . 1 E-3

104

(70)

22.4 m

Sm-155

Sm-154

2.7 E - l

105

(2)

62 d

Nb-91m

Mo-92, Nb-93

4 . 4 E-3

105

(23)

4.96 a

Eu-155

Gd-156

w

105

(23)

5.32 d

Tb-155

Dy-156

4 . 8 E-4

105

(12)

161 d

Lu-177m

H£-178, Lu-176

8 . 0 E-5

106

(0.09)

120 d

Gd-151

Gd-152

3 . 1 E-7 2.0 E - l

106

(22)

17.7 m

Yb-167

Yb-168

106

(11)

18.6 m

Re-188m

R e - 1 8 7 , Os-189

1.8 E-2

108

(56)

14.5 m

Ba-131m

Ba-132

7 . 3 E-2

108

(3)

1.3 m

Dy-165m

Dy-164

3 . 3 E-2

108

(13)

5 d

Ta-183

W-184

7 . 4 E-4

109

(0.3)

58 d

Te-125m

Te-126

2.6 E-5

109

(0.2)

40.2 h

La-140

La-139

2.4 E-5

110

(0.9)

10.5 s

Tb-158m

Tb-159

·>

110

(18)

30.7 d

Yb-169

Yb-170

5.0 E-3

111

(17)

38 d

Re-184

Re-185

3 . 4 E-2

112

(20)

7.5 h

Er-171

Er-170

4 . 8 E-3

113

(7)

6.71 d

Lu-177

L u - 1 7 6 , Hf-178

6.7 E-4

113

(21)

161 d

Lu-177m

H f - 1 7 8 , Lu-176

1.4 E-4

113

(54)

17.7 m

Yb-167

Yb-168

4.9 E-l

113

(1)

6.7 d

Lu-172

Lu-175

1.0 E-4

113

(7)

56.6 h

Ta-177

Ta-180

1.2 E-4

114

(2)

4.2 d

Yb-175

Yb-176, , Lu-176

2.2

114

(21)

1.73 h

Nd-149

Nd-150

5.4 E-l

221

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

114

(0.3)

70 d

Hf-175

Hf-176

9.6 E-5

114

(2)

115 d

Ta-182

W-183, Ta-181

4.8 E-5

114

(2)

11 h

Pt-189

Pt-190

2 Ε·-3

114

(10)

6.75 d

U-237

U-238

?

115

(20)

14 h

Os-183

Os-184

5.4 E-4

116

(95)

23 h

Cr-48

Cr-50

3.8 E-4

116

(0.5)

22 m

Rh-107

Pd-108

2.8 E-3

117

(25)

12.4 m

Nd-151

Nd-150

?

117

(2)

7.5 h

Er-171

Er-170

8.5 E-4

117

(2)

30.7 d

Yb-169

Yb-170

5.6 E-4

118

(4)

6.75 d

U-237

U-238

?

121

(16)

120 d

Se-75

Se-76

2.0 E-3

121

(0.4)

10.98 d

Nd-147

Nd-148

2.2 E-4

121

(34)

(33 m)

Ho-159

Er-162

?

122

(10)

1.7 m

Mn-57

Fe-58

7.1 E-3

122

(85)

270 d

Co-57

Ni-58, Co-59

5.2 E-2

122

(64)

19 s

Nd-90m

Mo-92

9.6 E-2

122

(64)

5.7 h

Mo-90

Mo-92

9.6 E-3

122

(31)

12.4 a

Eu-152

Eu-153

2.6 E-4

122

(6)

9.3 h

Eu-152m2

Eu-153

4.5 E-2

123

(0.2)

1.73 h

Nd-149

Nd-150

5.2 E-3

123

(40)

8.5

Eu-154

Eu-153, Gd-155

7.6 E-5

123

(0.7)

90.64 h

Re-186

Re-187, Os-187

2.0 E-2

124

(28)

11.5 d

Ba-131

Ba-132

4.2 E-4

124

(9)

7.5 h

Er-171

Er-170

2.1 E-3

124

(83)

23.6 h

Hf-173

Hf-174

1.5 E-2

125

(0.02)

75.1 d

W-185

W-186

3.1 E-5

125

(0.4)

94 d

Os-185

Os-186

1.4 E-5

126

(11)

3.7 d

Pd-100

Pd-102

1.1 E-3

126

(0.2)

10 h

Os-183m

Os-184

2.0 E-5

127

(15)

36 h

Ni-57

Ni-58

1.5 E - l

127

(2)

14 m

Tc-101

Ru-102,, Mo-100

3.2 E-3

127

(70)

3.a

Rh-101

Rh-103,, Pd-102

5.8 E-4

127

(0.6)

4.4 d

Rh-101m

Pd-102, Rh-103

5.3 E-3

127

(13)

2.9 h

Cs-134m

Cs-133, Ba-135

2.9

129

(51)

2.13 h

Ba-129m

Ba-130

1.1 E-2

129

(15)

161 d

Lu-177m

Hf-178, Lu-176

1.0 E-4

222 T a b . 5 - 5 , continued E,keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

129

(3)

2.8 d

Pt-191

Pt-192

1.5 E-3

129

(20)

45 s

Rh-105m

Pd-106, Ru-104

8 . 0 E-2

130

(27)

50 s

Kr-79m

Sr-84

w

130

(26)

15.4 d

Os-191

Os-192

2 . 0 E-4

130

(0.1)

2.5 h

Ir-195

Pt-196

3 . 8 E-5

130

(0.1)

3.8 h

Ir-195m

Pt-196

1 Ε -5

130

(3)

4.02 d

Pt-195m

Pt-196

1.8 E-2

130

(0.8)

183 d

Au-195

Au-197, Hg-196

5.7 E-5

130

(3)

7.8 s

Au-197m

Au-197, Hg-198, Pt-198

?

130

(0.2)

23.8 h

Hg-197m

Hg-198

3 . 4 E-4

131

(0.5)

40.2 h

La-140

La-139

6 . 0 E-5

131

(0.6)

3.1 h

Er-161

Er-162

1.2 E-3

131

(11)

30.7 d

Yb-169

Yb-170

3 . 1 E-3 3.9 E-6

131

(3)

22.1 h

Os-182

Os-184

132

(4)

1.68 m

W-185m

W-186

1.4 E-2

132

(23)

(33 m)

Ho-159

Er-162

·?

2.6 E-2

132

(3)

17.7 m

Yb-167

Yb-168

133

(0.02)

8.47 h

Pd-101

Pd-102

1.7

133

(4)

14.6 h

Nb-90

Mo-92

1.5 E-3

133

(2)

11.5 d

Ba-131

Ba-132

3 . 0 E-5

133

(40)

42.4 d

Hf-181

Hf-180

1.5 E-4

134

(0.04)

6.7 d

Lu-172

Lu-175

3 . 9 E-6

134

(0.1)

38 m

W-179

W-180

3 . 9 E-4

134

(9)

23.8 h

W-187

W-186

1.0 E-2

134

(34)

23.8 h

Hg-197m

Hg-198

5.7 E-2

135

(5)

23.6 h

Hf-173

Hf-174

9 . 0 E-4

135

(2)

73.5 h

Tl-201

Tl-203

6 . 0 E-3

136

(11)

270 d

Co-57

Ni-58, Co-59

6.7 E-3

136

(55)

120 d

Se-75

Se-76

7 . 1 E-3

136

(100)

50 s

Te-103

Ku-104

?

136

(8)

2.13 h

Ba-129m

Ba-130

1.7 E-3

136

(8)

42.4 d

Hf-181

Hf-180

2.9 E-5

136

(0.1)

121.2 d

W-181

W-182

9 . 1 E-3

136

(0.1)

4.32 d

Pt-193m

Pt-194

9.3 E-4

137

(0.09)

4.2 d

Yb-175

Yb-176, Lu-176

1.0 E-3

137

(9)

90.64 h

Re-186

Re-187, Os-187

2.6 E - l

138

(3)

54 m

In-116ml

In-115, Sn-117

2.7 E - l

Tab . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν * I

138

(2)

12.1 d

Ir-190

Ir-191

1.4 E-2

138

(1)

9.7 h

Au-196m

Au-197

139

(?)

144.4 d

Dy-159

Dy-160

1.2 E - l 9

139

(0.1)

56 h

Br-77

Br-79

2.2 E-4

139

(0.5)

1.73 h

Nd-149

Nd-150

1.3 E-2

139

(0.5)

28 h

Pm-151

Sm-152

1.0 E-4

139

(4)

30 h

Os-193

Os-192

3 . 9 E-4

139

(0.2)

39 m

Se-73m

Se-74

6 . 4 E-3

140

(34)

48 s

Ge-75m

Ge-76, S e - 8 0

3.4 E+5

140

(13)

23.6 h

Hf-173

Hf-174

2.5 E-3

141

(89)

6 h

Tc-99m

Ru-100 , Mo-100

4.2 E - l

141

(67)

14.6 h

Nb-90

Mo-92

2.5 E-2

141

(3)

11 h

Pt-189

Pt-190

2.9 E-3

143

(2)

17.7 m

Yb-167

Yb-168

1.8 E-2

144

(0.08)

8.1 h

Dy-157

Dy-158

2.9 E-5

144

(3)

5 d

Ta-183

W-184

1.7 E-4

145

(83)

46.5 h

Zn-72

Ge-76

2 . 1 E-3

145

(49)

32.51 d

Ce-141

Ce-142

2.7 E-2

145

(0.2)

2.5 h

Nd-141

Nd-142

3.2 E-2

145

(0.3)

4.2 d

Yb-175

Yb-176 , Lu-176

3 . 3 E-3

146

(3)

18.7 m

Eu-159

Gd-160

1.2 E-2

147

(45)

32 m

Cl-34m

Cl-35, K-39

4.3

147

(0.2)

19.5 m

Tb-163

Dy-164

7 . 2 E-4

147

(36)

16 m

Ta-182m

W-183, Ta-181

3 . 6 E-4

147

(2)

24.3 h

Re-189

Os-190

4 . 6 E-4

147

(0.5)

10 h

Os-183

Os-184

5 . 0 E-5

148

(0.03)

3.1 h

Er-161

Er-162

6 . 2 E-4

148

(43)

9.7 h

Au-196m

Au-197

5.1

149

(2)

5.32 d

Tb-155

Dy-156

4 . 2 E-5

149

(?)

64 h

Re-182

Re-185, Os-184

?

150

(53)

9.5 d

Gd-149

Gd-152

1.4 E-5

150

(68)

25 m

Te-131

Te-130

4 . 2 E-4

150

(0.04)

17.7 m

Tb-167

Tb-168

3 . 6 E-4

150

(20)

1.9 h

Yb-177

Yb-176

3.8 E-3

150

(30)

49 m

Cd-lllm

Cd-112

1.2 E - l

151

(74)

4.48 h

Kr-85m

Rb-87

6.6 E-2

151

(12)

67.7 m

Sr-85m

Sr-86

1.3

224 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

151

(0.01)

46.75 h

Sm-153

Sm-154

4 . 4 E-4

152

(8)

4.6 m

Ho-169

Er-170

1.1 E - l

152

(7)

115 d

Ta-182

W-183, Ta-181

1.7 E-4

152

(0.2)

121.1 d

W-181

W-182

1.8 E-2

153

(12)

42 m

Cr-49

C r - 5 0 , Fe-54

2.3 E - l

153

(66)

4.7 d

Te-119m

Te-120

2 . 6 E-4

153

(8)

13 d

Cs-136

Ba-137

8 . 8 E-5

153

(18)

161 d

Lu-177m

Hf-178, Lu-176

1.2 E-4

154

(0.2)

1.3 m

Dy-165m

Dy-164

2.2 E-3

154

(0.1)

3.85 d

Sb-127

Te-128

1.5 E-5

154

(7)

120 d

Gd-151

Gd-152

2 . 4 E-5

154

(0.3)

19.5 m

Tb-163

Dy-164

1 . 1 E-3

155

(13)

20.8 m

In-112m

In-113

5.0 E-l

155

(15)

16.98 h

Re-188

Re-187, Os-189

8 . 6 E-2

155

(30)

41.5 h

Ir-188

Ir-191

2 . 3 E-4

155

(0.5)

41.2 d

Ag-105

Ag-107, Cd-106

1.3 E-4

156

(7)

1.73 h

Nd-149

Nd-150

1.8 E - l

156

(3)

115 d

Ta-182

W-183, Ta-181

6 . 1 E-5

157

(0.2)

4.4 d

Rh-101m

Pd-102, Rh-103

1.7 E-3

157

(0.5)

2.5 h

Ho-161

Er-162

1.9 E-4

158

(100)

6.1 d

Ni-56

Ni-58

2 . 1 E-3

158

(0.03)

8.47 h

Pd-101

Pd-102

2.5 E-2

158

(39)

3.13 d

Au-199

Hg-200

2.3 E-3

158

(52)

42.6 m

Hg-199m

Hg-200

2.8

159

(84)

14 d

Sn-117m

Sn-118

5.0 E - l

159

(70)

3.42 d

Sc-47

T i - 4 8 , Ca-48

6.7 E-2

159

(2)

3.7 d

Pd-100

Pd-102

2 . 0 E-4

159

(14)

1.95 h

In-117m

Sn-118

6 . 6 E-3

159

(86)

40.1 m

Sn-123m

Sn-124

5.1

159

(84)

119.7 d

Te-123m

Te-124

1.8 E-3

160

(10)

54 s

Ge-77m

Ge-76

7 . 1 E-3

160

(1)

18.7 m

Eu-159

Gd-160

4 . 1 E-3

4.6 m

Ho-169

Er-170

1.4 E-2

160

(1)

161

(0.03)

17.7 m

Yb-167

Yb-168

2.8 E-4

161

(10)

5 d

Ta-183

W-184

5.7 E-4

162

(0.02)

36 h

Ni-57

Ni-58

2 . 0 E-4

162

(52)

17.5 s

Se-77m

Se-78

5.7 E-2

225 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

162

(52)

17.5 s

Se-77m

Se-78

5.7 E-2

162

(0.1)

38.8 h

As-77

Se-78, Br-81

8 . 5 E-5

162

(1)

56 h

Br-77

Br-79

2.2 E-3

162

(1)

9.59 h

Dy-155

Dy-156

1 . 5 E-4

162

(7)

23.6 h

Hf-173

Hf-174

1.3 E-3

162

(24)

71 d

Ke-183

Re-185, Os-184

7 . 0 E-3

163

(6)

5.7 h

Mo-90

Mo-92

9 . 0 E-4

163

(2)

28 h

Pm-151

Sm-152

4 . 0 E-4

163

(7)

5.32 d

Tb-155

Dy-156

1.4 E-4

163

(0.1)

10 h

Os-183m

Os-184

1.0 E-4

163

(0.7)

94 d

Os-185

Os-186

2 . 5 E-5

164

(5)

13 d

Cs-136

Ba-137

5 . 5 E-5

164

(0.6)

1.68 m

W-185m

W-186

2.2 E-3

165

(0.3)

23.8 h

Hg-197m

Hg-198

5 . 1 E-4

165

(2)

6.75 d

U-237

U-238

?

166

(22)

82.7 m

Ba-139

Ba-138

2.4 E-3

166

(80)

137.5 d

Ce-139

Ce-140

1.1 E-l

167

(0.6)

19.5 m

Tb-163

Dy-164

2.2 E-3

167

(9)

73.5 h

Tl-201

Tl-203

2.7 E-2

168

(8)

28 d

Pm-151

Sm-152

1.6 E-3

168

(8)

14 h

Os-183

Os-184

2.2 E-4

Au-197

9.6 E-l

168

(8)

9.7 h

Au-196m

169

(0.4)

34.4 h

Ce-137

Ce-138

1.8 E-5

169

(99)

8.2 h

Fe-52

Fe-54

?

169

(0.16)

17.7 m

Yb-167

Yb-168

1.5 E-3

171

(89)

2.83 d

In-111

S n - 1 1 2 , In-113

4.6 E-l

171

(0.39)

10 h

Os-183m

Os-184

3.9 E-5

171

(2)

1.37 a

Lu-173

L u - 1 7 5 , Hf-174

1.3 E-4

172

(47)

16 m

Ta-182m

W-183, Ta-181

4.7 E-4

172

(3)

2.8 d

Pt-191

Pt-192

1.6 E-3

173

(0.08)

46.75 h

Sm-153

Sm-154

3 . 5 E-3

173

(7)

3.8 h

Ir-195m

Pt-196

1 . 1 E-3

174

(0.1)

40.2 h

La-140

La-139

1.2 E-5

174

(12)

161 d

Lu-177m

Hf-178, Lu-176

174

(22)

49 m

Ta-184m

W-186

8 . 0 E-5 ?

174

(3)

1.68 m

W-185m

W-186

1 . 1 E-2

174

(82)

16.3 m

K-45

Ca-46

3 . 5 E-5

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

168

(8)

28 d

Pm-151

Sm-152

1.6 E-3

168

(8)

14 h

Os-183

Os-184

2.2 E-4

168

(8)

9.7 h

Au-196m

Au-197

9.6 E - l

169

(0.4)

34.4 h

Ce-137

Ce-138

1.8 E-5

169

(99)

8.2 h

Fe-52

Fe-54

9

169

(0.16)

17.7 m

Yb-167

Yb-168

1.5 E-3

171

(89)

2.83 d

In-111

Sn-112

171

(0.39)

10 h

Os-183m

Os-184

In-113

4.6 E - l 3.9 E-5

171

(2)

1.37 a

Lu-173

Lu-175

172

(47)

16

Ta-182m

W-183, Ta-181

4.7 E-4

172

(3)

2.8 d

Pt-191

Pt-192

1.6 E-3 3.5 E-3

m

Hf-174

1.3 E-4

173

(0.08)

46.75 h

Sm-153

Sm-154

173

(7)

3.8 h

Ir-195m

Pt-196

1.1 E-3

174

(0.1)

40.2 h

La-140

La-139

1.2 E-5

174

(12)

161 d

Lu-177m

Hf-178, Lu-176

8.0 E-5

174

(22)

49 m

Ta-184m

W-186

?

174

(3)

1.68 m

W-185m

W-186

1.1 E-2

174

(82)

16.3 m

K-45

Ca-46

3.5 E-5

175

(6)

43.67 h

Sc-48

Ti-49

1.9 E-3

175

(0.2)

21.1 m

Ga-70

Ga-71, Ge-72, As-75

1.1 E-2

175

(4)

120 d

Gd-151

Gd-152

1.3 E-5

176

(0.4)

2.5 h

Ho-161

Er-162

2.2 E-4

176

(23)

17.7 m

Yb-167

Yb-168

2.1 E - l

177

(12)

2.13 h

Ba-129m

Ba-130

2.5 E-3

177

(0.3)

32.06 h

Cs-129

Ba-130

3.9 E-5

177

(14)

13 d

Cs-136

Ba-137

1.6 E-4

177

(4)

28 h

Pm-151

Sm-152

8.0 E-4

177

(1)

18.7 m

Eu-159

Gd-160

4.1 E-3

177

(0.7)

19.5 m

Tb-163

Dy-164

2.5 E-3

177

(22)

30.7 d

Yb-169

Yb-170

6.2 E-3

177

(3)

161 d

Lu-177m

Hf-178, Lu-176

2.0 E-5

178

(26)

49 m

Ta-185

W-186

?

178

(12)

80 s

Kh-109

Pd-110

2.5 E-2

178

(6)

(33 m)

Ho-159

Er-162

9

179

(6)

64 h

Ke-182

Re-185

Os-184

1.2 E-4

179

(0.8)

1.37 a

Lu-173

Lu-175, Hf-174

5.5 E-5

179

(1)

2.8 d

Pt-191

Pt-192

5.3 E-4

227 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν · I

179

(3)

115 d

Ta-182

W-183, Ta-181

7.2 E-5

180

(0.5)

4.4 d

Rh-101m

Pd-102, Rh-103

4 . 4 E-3

180

(7)

5.32 d

Tb-155

Dy-156

1.5 E-4

180

(33)

22.1 h

Os-182

Os-184

4 . 3 E-5

180

(0.4)

30 h

Os-193

Os-192

3 . 9 E-5

180

(2)

9.5 h

Hg-195

Hg-196

1.5 E-3

181

(0.3)

56 h

Br-77

Br-79

6 . 6 E-4

181

(6)

66 h

Mo-99

Mo-100

1.9 E-2 8 . 0 E-4

181

(0.8)

3.6 m

Gd-161

Gd-160

181

(20)

6.7 d

Lu-172

Lu-175

1.9 E-3

181

(62)

18.7 h

Au-200m

Hg-201

3.2 E-6

181

(1)

39 m

Se-73m

Se-74

3.2 E-2

182

(100)

2.13 h

Ba-129m

Ba-130

2 . 1 E-2

182

(9)

150 a

Tb-158

Tb-159

1.9 E-5

182

(2)

8.1 h

Dy-157

Dy-158

7.2 E-4

182

(3)

63.6 h

Tm-172

Yb-173

1.7 E-4

183

(0.4)

41.2 d

Ag-105

Ag-107, Cd-106

1.0 E-4

184

(1)

14 m

Tc-101

Ru-102, Mo-100

1.6 E-3

184

(0.1)

4.4 d

Rh-101m

Pd-102, Rh-103

8.7 E-4

Tm-169

5 . 6 E-4

184

(16)

7.7 h

Tm-166

184

(17)

93.1 d

Tm-168

Tm-169

2.9 E-2

184

(16)

6.24 d

Bi-206

Bi-209

4.7 E-4

185

(4)

9.59 h

Dy-155

Dy-156

6 . 1 E-4

185

(47)

61.9 h

Cu-67

Zn-68, Ga-71

8 . 0 E-2

185

(24)

78.3 h

Ga-67

Ga-69

4 . 6 E-2

185

(17)

7.6 m

Tb-162

Dy-163

5.8 E-2

185

(29)

68 m

Ho-162m

Ho-165

1.1 E - l

185

(23)

16 m

Ta-182m

W-183, Ta-181

2.3 E-4

186

(2)

24.3 h

Ke-189

Os-190

4 . 6 E-4

187

(0.06)

56 h

Br-77

Br-79

1.3 E-4

187

(79)

9.9 m

0s-190m

I r - 1 9 1 , Os-192

2.3

187

(52)

12.1 d

Ir-190

Ir-191

3.7 E - l

187

(68)

3.1 h

Ir-190m

Ir-191

2.0

187

(1)

11 h

Pt-189

Pt-190

1.0 E-3

188

(0.8)

1.68 m

W-185m

W-186

2.9 E-3

188

(19)

10.2 d

Pt-188

Pt-190

7 . 3 E-4

188

(0.4)

2.8 d

Pt-191

Pt-192

2 . 1 E-4

228 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

187

(52)

12.1 d

Ir-190

Ir-191

3.7 E-1

187

(68)

3.1 h

Ir-190m

Ir-191

2.0

187

(1)

11 h

Pt-189

Pt-190

1.0 E-3

188

(0.8)

1.68 m

W-185m

W-186

2.9 E-3

188

(19)

10.2 d

Pt-188

Pt-190

7 . 3 E-4

188

(0.4)

2.8 d

Pt-191

Pt-192

2 . 1 E-4

188

(38)

9.7 h

Au-196m

Au-197

4.5

189

(58)

4.69 m

Pd-109m

Pd-110

1.2

189

(2)

1.73 h

Nd-149

Nd-150

5.2 E-2

190

(17)

49.5 d

In-114m

In-115, Sn-115

3.9 E-2

190

(1)

41.3 d

Pm-148m

Sm-149

2 . 0 E-6

190

(0.1)

12.1 d

Ir-190

Ir-191

7 . 2 E-4

191

(4)

20 h

Pt-197

Pt-198

9 . 1 E-2

191

(0.5)

64.1 h

Hg-197

Hg-198

7 . 0 E-4

192

(20)

14.6 m

Mo-101

Mo-100

1 . 1 E-2

192

(0.7)

1.73 h

Nd-149

Nd-150

194

(1)

( 2 0 . 9 m)

Pm-141

Sm-144

1.8 E-2 9

195

(0.6)

2.2 h

Rh-106m

Pd-108

4 . 0 E-3

195

(0.3)

8.3 d

Ag-106m

Ag-107

1.3 E-4

195

(18)

10.2 d

Pt-188

Pt-190

6 . 9 E-4

197

(100)

5.76 d

Sb-120m

Sb-121

7 . 5 E-2

197

(0.2)

10.98 d

Nd-147

Nd-148

1 . 1 E-4

197

(74)

22.6 m

Sm-141m

Sm-144

w

197

(5)

72.1 d

Tb-160

Tb-159, , Dy-161

197

(14)

(5 h)

Ho-160n

Er-162

2 . 2 E-4 ι

197

(6)

12.1 d

Ir-190

Ir-191

4 . 3 E-2

198

(70)

3 a

Rh-101

Rh-103,, Pd-102

5 . 8 E-4

198

(50)

93.1 d

Tm-168

Tm-169

8 . 5 E-2

198

(36)

30.7 d

Yb-169

Yb-170

9 . 9 E-3

115 d

Ta-182

W-183, Ta-181

2 . 4 E-5

198

(1)

199

(1)

120 d

Se-75

Se-76

1.3 E-4

199

(1)

83 m

Ge-75

Ge-76, S e - 8 0

1.9 E-1

199

(1.0)

1.73 h

Nd-149

Nd-150

2.6 E-2

199

(0.8)

15.2 d

Eu-156

Gd-157

7 . 5 E-6

199

(42)

5.35 d

Tb-156

Tb-159

5 . 0 E-4

200

(1)

56 h

Br-77

Br-79

2.2 E-3

200

(0.04)

9.5 h

Hg-195

Hg-196

3 . 1 E-5

229 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν · I

200

(1)

40 h

Hg-195m

Hg-196

2 . 4 E-5

201

CI)

3.2 h

Erl61

Er-162

2 . 1 E-3

202

(39)

2.13 h

Ba-129m

Ba-130

8 . 2 E-3

202

(0.07)

23.8 h

Hg-197m

Hg-198

1.2 E-4

202

(0.04)

6.24 d

Bi-206

Bi-209

1.2 E-6

202

(97)

3.19 h

Y-90m

Zr-91

1.2 E - l

203

(6)

5.7 h

Mo-90

Mo-92

9 . 1 E-4

203

(0.06)

9.35 h

Te-127

Te-128

6.6 E-3

203

(5)

6.7 d

Lu-172

Lu-175

4 . 8 E-4

204

(66)

60 d

Tc-95m

Ru-96

1 . 1 E-3

204

(14)

161 d

Lu-177m

Hf-178, Lu-176

9 . 4 E-5

206

(8)

17 h

Ce-135

Ce-136

2.9 E-3

206

(0.4)

9.59 h

Dy-155

Dy-156

6 . 0 E-5

206

(9)

36 m

Er-159

Er-162

206

(40)

(8.3 s)

Ho-159m

Er-162

w ?

206

(0.1)

23.8 h

W-187

W-186

1 . 1 E-4

206

(3)

74 d

Ir-192

Ir-193

3 . 9 E-3

207

(2)

9.5 h

Hg-195

Hg-196

1.6 E-3

207

(0.5)

40 h

Hg-195m

Hg-196

1.2 E-5

208

(3)

1.73 h

Nd-149

Nd-150

7 . 8 E-2

208

(5)

3.1 h

Ho-167

Er-168

208

(41)

(2.3 s)

Er-167m

Tm-169

6 . 2 E-3 ?

208

(41)

9.25 h

Tm-167

Tm-169, Yb-168

1.5 E - l

208

(11)

6.71 d

Lu-177

Lu-176, Hf-178

1 . 1 E-3

208

(61)

161 d

Lu-177m

Hf-178, Lu-176

4 . 2 E-4

208

(0.8)

56.6 h

Ta-177

Ta-180

1.4 E-5

208

(2)

12.1 d

Ir-190

Ir-191

1.4 E-2

208

(8)

3.13 d

Au-199

Hg-200

208

(23)

6.75 d

U-237

U-238

4.7 E-4 7

209

(2)

78.3 h

Ga-67

Ga-69

3 . 8 E-3

209

(2)

4.4 m

In-118m

Sn-119

9 . 4 E-5

209

(0.2)

69.6 m

Te-129

Te-130

3 . 8 E-2

209

(2)

28 h

Pm-151

Sm-152

4 . 0 E-4

209

(3)

71 d

Re-183

R e - 1 8 5 , Os-184

8.7 E-4

209

(0.1)

2.8 d

Pt-191

Pt-192

5 . 3 E-5

210

(5)

5 d

Ta-183

W-184

2.9 E-4

211

(29)

11.3 h

Ge-77

Se-82

7 . 0 E-5

230 T a b . 5 - 5 , continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

211

(31)

211

(0.2)

1.73 h

Nd-149

Nd-150

8.0 E-l

2.5 h

Ho-161

Er-162

211

7 . 4 E-5

(12)

3.1 h

Er-161

Er-162

2.6 E-2

211

(0.6)

7.5 h

Er-171

Er-170

211

(?)

2.5 h

Ir-195

Pt-196

1.4 E-4 9

211

(?)

3.8 h

Ir-195m

Pt-196

9

212

(83)

154 d

Te-121m

Te-122

6 . 0 E-4

212

(0.7)

19.5 m

Tb-163

Dy-164

2 . 5 E-3

213

(82)

22.7 m

Lu-178m

Hf-179

2.8 E-2

213

(0.1)

9.25 m

Ta-178

Ta-180, , W-180

4 . 4 E-3

214

(68)

21.3 s

Pd-107m

Pd-108, , Ag-109

1.6

214

(12)

4.6 h

Lu-179

Hf-180

?

214

(87)

2.13 h

Ba-129m

Ba-130

1.8 E-2

214

(0.5)

1.73 h

Nd-149

Nd-150

1.3 E-2

214

(80)

2.2 h

Ta-178m

Ta-180, , W-180

1.8 E - l

214

(95)

18.7 s

Hf-179m

Hf-180, T a - 1 8 0

9 . 5 E+l

215

(37)

21 m

Rb-84m

R b - 8 5 , S r - 8 6 , Y-89

1.7 E+2

215

(2)

80 s

Rh-109

Pd-110

4 . 2 E-3

215

(82)

5.5 h

Hf-180m

T a - 1 8 1 , Hf-180

2 . 2 E-2

216

(91)

2.9 d

Ru-97

Ru-98

3.4 E - l

216

(4)

72.1 d

Tb-160

Tb-159, , Dy-161

1.7 E-4

216

(26)

11.3 h

Ge-77

Se-82

6 . 2 E-5

216

(22)

54 s

Ge-77m

S e - 8 2 , Ge-76

2 . 1 E-2

216

(22)

11.5 d

Ba-131

Ba-132

3 . 4 E-4 1.8 E-4

216

(5)

7.7 h

Tm-166

Tm-169

216

(10)

165 d

Re-184m

Re-185

•>

218

(0.9)

150 a

Tb-158

Tb-159

2 . 0 E-6

219

(4)

23.4 h

Nb-96

Mo-97

3 . 1 E-3

219

(10)

24.3 h

Re-189

Os-190

2.3 E-3

219

(0.3)

30 h

Os-193

Os-192

2.9 E-5

220

(0.8)

2.8 d

Pt-191

Pt-192

4 . 2 E-4

221

(2)

35.34 h

Br-82

B r - 8 1 , Rb-87

9.6 E-5

221

(53)

2.13 h

Ba-129m

Ba-130

1 . 1 E-2

221

(0.6)

5.32 d

Tb-155

Dy-156

1.3 E-4

221

(6)

22.2 h

K-43

Ca-44

2.4 E-3

222

(7)

8.3 d

Ag-106m

Ag-107

2.9 E-3

222

(8)

115 d

Ta-182

W-183, T a - 1 8 1

1.9 E-4

231

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

222

(9)

6.7 m

W-179m

W-180

3.0 E-3

223

(0.09)

1.37 a

Lu-173

Lu-175, Hf-174

6.1 E-6

224

(4)

12.1 d

Ir-190

Ir-191

2.8 E-2

226

(0.2)

18.56 h

Gd-159

Gd-160

8.8 E-3

227

(0.2)

1.73 h

Nd-149

Nd-150

5.2 E-3

227

(68)

9.59 h

Dy-155

Dy-156

1.0 E-2

228

(2)

18.7 m

Eu-159

Gd-160

7.9 E-3

228

(37)

161 d

Lu-177m

Hf-178, Lu-176

2.5 E-4

229

(2)

8.3 d

Ag-106m

Ag-107

8.4 E-4

229

(0.3)

6.7 d

Lu-172

Lu-175

2.9 E-5

229

(4)

115 d

Ta-182

W-183, Ta-181

9.6 E-5

229

(27)

64 h

Re-182

Re-185, Os-184

5.4 E-4

230

(32)

20 m

Ag-115

Cd-116

5.4 E-3

230

(0.6)

1.73 h

Nd-140

Nd-150

1.6 E-2

230

(0.8)

70 d

Hf-175

Hf-176

2.5 E-4

230

(0.8)

10 h

Os-183m

Os-184

8.0 E-5

231

(0.2)

55 m

Cd-105

Cd-106

1.1 E-4

231

(1)

53.38 h

Cd-115

Cd-116

6.1 E-3

231

(0.08)

72.1 d

Tb-160

Tb-159,, Dy-161

3.4 E-6

232

(85)

67.7 m

Sr-85m

Sr-86

9.4

232

(0.2)

22 m

Rh-107

Pd-108

1.1 E-3

232

(1)

28 h

Pm-151

Sm-152

2.0 E-4

6.7 d

Lu-172

Lu-175

2.9 E-5

233

(0.3)

233

(0.3)

1.37 a

Lu-173

Lu-175, Hf-174

2.0 E-5

234

(0.3)

39 h

Ge-69

Ge-70, Se-74

3.6 E-3

234

(3)

14 m

Tc-101

Ru-102,, Mo-100

4.8 E-3

234

(0.2)

4.4 d

Kh-101m

Pd-102, Rh-103

1.8 E-3

234

(0.4)

94 d

Os-185

Os-186

1.5 E-5

234

(0.3)

6.24 d

Bi-206

Bi-209

8.7 E-6

235

(25)

86.6 h

Nb-95m

Mo-96

2.1 E-3

235

(0.4)

12.1 d

Ir-190

Ir-191

2.8 E-3

236

(0.5)

3.1 h

Er-161

Er-162

1.0 E-3

236

(3)

14 h

Os-183

Os-184

8.1 E-5

237

(0.3)

7.5 h

Er-171

Er-170

7.2 E-5

238

(3)

14 m

Tc-101

Ru-102,, Mo-100

4.8 E-3

238

(0.2)

4.4 d

Rh-101m

Pd-102, Rh-103

1.7 E-3

72.1 d

Tb-160

Tb-159,, Dy-161

4.3 E-7

238

(0.01)

T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

238

(5)

3.1 h

Ho-167

Er-168

6.0 E-3

239

(2)

38.8 h

As-77

Se-78,

239

(22)

56 h

Br-77

Br-79

4 . 8 E-2

239

(0.3)

67.7 m

Sr-85m

Sr-86

3 . 1 E-2

239

(0.2)

120 d

Gd-151

Gd-152

6.8 E-7

239

(0.2)

5.32 d

Tb-155

Dy-156

4 . 2 E-6

239

(0.2)

2.7 m

W-179m

W-180

6.8 E-5

239

(46)

1.8 h

Os-181

Os-184

?

240

(0.06)

4.02 d

Pt-195m

Pt-196

3.5 E-4

240

(3)

11.5 d

Ba-131

Ba-132

4 . 5 E-5

240

(5)

1.73 h

Nd-149

Nd-150

1.3 E - l

240

(3)

28 h

Pm-151

Sm-152

6 . 0 E-4

241

(4)

23.4 h

Nb-96

Mo-97

3 . 1 E-3

242

(0.4)

40.2 h

La-140

La-139

4 . 8 E-5

242

(0.08)

9.5 h

Hg-195

Hg-196

6.2 E-5

243

(2)

9.13 h

Zn-62

Zn-64

1 . 6 E-3

243

(7)

120 d

Gd-151

Gd-152

2 . 4 E-5

244

(4)

11 h

Pt-189

Pt-190

3.9 E-3

245

(8)

12.4 a

Eu-152

Eu-153

6.7 E-5

245

(94)

2.83 d

In-111

S n - 1 1 2 , In-113

4.9 E - l

245

(3)

24.3 h

Re-189

Os-190

6 . 9 E-4

245

(6)

3.3 d

Ir-189

I r - 1 9 1 , Pt-190

2.9 E-3

246

(0.9)

7.5 d

Ag-111

Cd-112

9

246

(?)

1.2 m

Ag-lllm

Cd-112

1

246

(94)

49 m

Cd-lllm

Cd-112

3.7 E - l

246

(1)

1.73 h

Nd-149

Nd-150

2 . 6 E-2

246

(36)

22.4 m

Sm-155

Sm-154

1.6 E-2 2 . 1 E-3

Br-81

1.7 E-3

246

(36)

5 d

Ta-183

W-184

246

(2)

71 d

Re-183

R e - 1 8 5 , Os-184

5.8 Er-4

246

(0.1)

23.8 h

W-187

W-186

1 . 1 E-4

246

(0.3)

10 h

Os-183m

Os-184

3 . 0 E-5

247

(0.4)

6.7 d

Lu-172

Lu-175

248

(65)

21 m

Rb-84m

Rb-85, Sr-86,

3 . 9 E-5 Y-89

3 . 1 E+2

249

(4)

11.5 d

Ba-131

Ba-132

5 . 9 E-5

250

(0.4)

38.8 h

As-77

Se-78, Br-81

3.5 E-4

250

(3)

56 h

Br-77

Br-79

6 . 6 E-3

250

(?)

50 s

Rh-109m

Pd-110

?

233 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν * I

250

(0.2)

6.71 d

Lu-177

Lu-176, Hf-178

1.9 E-5 7.6 E-4

251

(0.4)

69.6 m

Te-129

Te-130

251

(7)

19.5 m

Tb-163

Dy-164

2.6 E-2

251

(0.08)

4.2 d

Yb-175

Y b - 1 7 6 , Lu-176

8.7 E-4

252

(0.4)

10 h

Os-183m

Os-184

4 . 0 E-5

252

(8)

3.85 d

Sb-127

Te-128

1 . 1 E-3

253

(0.7)

60 d

Tc-95m

Ru-96

1 . 1 E-5

253

(100)

2.1 m

Ga-75

Ge-76

9

253

(14)

(33 m)

Ho-159

Er-162

?

253

(0.5)

3.1 h

Er-161

Er-162

1 . 1 E-3

253

(3)

38 d

Re-184

Re-185

6 . 0 E-3

253

(0.1)

55 m

Cd-105

Cd-106

5.7 E-5

254

(3)

39 m

Se-73m

Se-74

9.7 E-2

254

(14)

2.6 m

Nb-99

Mo-100

2 . 6 E-2

254

(11)

34.4 h

Ce-137m

Ce-138

5.0 E-4

255

(2)

115.1 d

Sn-113

Sn-114

3.0 E-5

255

(0.2)

4.5 h

Pr-139

Pr-141

2.0 E - l

255

(0.6)

93.1 d

Eu-149

Eu-151

8 . 4 E-5

256

(17)

12.4 m

Nd-151

Nd-150

·>

256

(10)

64 h

Re-182

Re-185, Os-184

1.8 E-4

256

(80)

18.7 h

Au-200m

Hg-201

4.1 E-6

257

Mo-92

1.2 E-2

(78)

5.7 h

Mo-90

257

(?)

(3.9 s)

Au-193m

Hg-196

·>

258

(60)

11.1 h

Hg-193m

Hg-196

w

258

(0.4)

1.73 h

Nd-140

Nd-150

1.0 E-2

258

(0.5)

28 h

Pm-151

Sm-152

1.0 E-4

259

(2)

5.37 h

Ag-113

Cd-114

1.0 E-3

260

(1)

9.13 h

Zn-62

Zn-64

8 . 2 E-4

260

(0.05)

18 m

Se-81

Se-82

2.7 E-4

260

(0.01)

57.3 m

Se-81m

Se-82

2 . 6 E-5

260

(80)

7.6 m

Tb-162

Dy-163

2.7 E - l

260

(0.6)

19.5 m

Tb-163

Dy-164

2 . 1 E-3

261

(13)

34.9 h

Kr-79

Sr-84

w

261

(3)

53.38 h

Cd-115

Cd-116

1.8 E-3

262

(5)

5.32 d

Tb-155

Dy-156

1.0 E-4

262

(2)

9.5 h

Hg-195

Hg-196

1.5 E-3

262

(38)

40 h

Hg-195m

Hg-196

8 . 8 E-4

234 T a b . 5 - 5 , continued E.keV ' (1%)

Τ

263

(0.4)

39 m

263

(57)

6.9 h

263

(0.2)

55 m

263

(3)

264

(0.02)

264

(4)

265 265

Nuclide

Target Nuclide

Ν ' I

Se-73m

Se-74

1.2 E-2

Mo-93m

Mo-94

1.9 E - l

Cd-105

Cd-106

1.1 E-4

6.24 d

Bi-206

Bi-209

8.7 E-5

14.6 a

Cd-113m

Cd-114

w

115 d

Ta-182

W-183, Ta-181

9 . 6 E-5

(50)

11.3 h

Ge-77

Se-82

1.2 E-4

(11)

83 m

Ge-75

Ge-76, Se-80

2.1

265

(59)

120 d

Se-75

Se-76

7 . 6 E-3

265

(0.6)

6.7 d

Lu-172

Lu-175

5.8 E-5

266

(42)

17 h

Ce-135

Ce-136

1.6 E-2

266

(0.3)

22 m

Rh-107

Pd-108

1.6 E-3

267

(6)

10.1 h

Y-93

Zr-94

6 . 6 E-3

267

(0.3)

32.06 h

Cs-129

Ba-130

3.9 E-5

267

(0.5)

40.2 h

La-140

La-139

6 . 0 E-5

268

(16)

28.7 h

Ba-135m

Ba-136

4 . 2 E-2

268

(2)

2.8 d

Pt-191

Pt-192

1.1 E-3

269

(0.3)

20 h

Pt-197

Pt-198

6 . 6 E-3

269

(0.04)

64.1 h

Hg-197

Hg-198

5 . 6 E-5

270

(34)

6.1 d

Ni-56

Ni-58

7 . 1 E-4

270

(7)

8.47 h

Pd-101

Pd-102

5.8

270

(19)

1.73 h

Nd-140

Nd-150

5.0 E - l

270

(2)

6.7 d

Lu-172

Lu-175

1.9 E-4

271

(86)

2.44 d

Sc-44m

S c - 4 5 , Ti-46

1.4 E - l

271

(0.3)

56 h

Br-77

Br-79

6.6 E-4

271

(0.1)

16 h

Te-119

Te-120

5.1 E-5

271

(27)

4.7 d

Te-119m

Te-120

1 . 1 E-4

271

(1)

9.59 h

Dy-155

Dy-156

1.5 E-4

272

(13)

1.37 a

Lu-173

Lu-175, Hf-174

8 . 9 E-4

272

(0.3)

8.83 m

Sm-143

Sm-144

5.7 E-2

273

(0.7)

142 d

Lu-174m

Lu-175

6 . 0 E-5

274

(13)

13 d

Cs-136

Ba-137

1.5 E-4

274

( 0 . 0 0 5 ) 18.56 h

Gd-159

Gd-160

2.2 E-4

275

(0.8)

10.98 d

Nd-147

Nd-148

4 . 3 E-4

275

(0.7)

1.73 h

Nd-149

Nd-150

1.8 E-2

275

(6)

28 h

Pm-151

Sm-152

1.2 E-3

Se-82

4 . 9 E-3

276

(0.9)

18 m

Se-81

235 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν * I

276

(0.7)

57.3 m

Se-81m

Se-82

1.8 E-3

276

(8)

38.9 h

Ba-133m

Ba-134

1.0 E-2

276

(0.09)

3.1 h

Er-161

Er-162

1.9 E-4

276

(9)

64 h

Re-182

Re-185, , Os-184

1.8 E-4

277

(3)

93.1 d

Eu-149

Eu-151

4.2 E-4

277

(0.6)

7.5 h

Er-171

Er-170

1.5 E-4

277

(96)

88 m

Ge-78

Se-82

2 . 9 E-3

278

(2)

22 m

Rh-107

Pd-108

1.1 E-2

278

(0.6)

69.6 m

Te-129

Te-130

1.2 E-2

279

(2)

32.06 h

Cs-129

Ba-130

2.6 E-4

279

(2)

81 m

Pt-197m

Pt-198

4 . 5 E-2

279

(73)

(7.8 s)

Au-197m

Pt-198

?

279

(0.2)

40 h

Hg-195m

Hg-196

4.7 E-6

279

(5)

23.8 h

Hg-197m

Hg-198

8 . 5 E-3

279

(82)

46.6 d

Hg-203

Hg-204

3 . 0 E-2

279

(81)

52.1 h

Pb-203

Pb-204

1.1 E - l

280

(0.5)

2.35 h

Dy-165

Dy-164

4 . 8 E-3

280

(1)

6.7 d

Lu-172

Lu-175

1 . 0 E-4

280

(25)

120 d

Se-75

Se-76

3 . 3 E-3

280

(32)

41.2 d

Ag-105

Ag-107,, Cd-106

8 . 3 E-3

280

(1)

6.7 d

Lu-172

Lu-175

1.0 E-4

280

(0.2)

35.5 h

Rh-105

Pd-106

1.7 E-4

281

(0.6)

3.85 d

Sb-127

Te-128

9 . 0 E-5

281

(0.2)

5.32 d

Tb-155

Dy-156

4.2 E-6

281

(1)

30 h

Os-193

Os-192

9.7 E-5

282

(0.06)

38.8 h

As-77

Se-78, Br-81

5.2 E-5

282

(2)

56 h

Br-77

Br-79

4 . 4 E-3

283

(13)

3.3 h

Cu-61

Cu-63

1.6 E - l

283

(98)

4 h

Sn-110

Sn-112

3.0 E-l

283

(0.7)

1.73 h

Nd-149

Nd-150

1.8 E-2

283

(6)

3.6 m

Gd-161

Gd-160

6 . 0 E-3

283

(11)

68 m

Ho-162m

Ho-165

3.9 E-2

283

(3)

4.2 d

Yb-175

Yb-176, , Lu-176

3 . 3 E-2

283

(0.2)

6.7 m

W-179m

W-180

7 . 8 E-4

283

(0.5)

12.1 d

Ir-190

Ir-191

3 . 6 E-3

283

(0.3)

74 d

Ir-192

Ir-193

3 . 9 E-4

285

(0.4)

1.37 a

Lu-173

Lu-175, Hf-174

2.7 E-5

T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν* I

286

(3)

53.1 h

Pm-149

Sm-150

2.4 E-3

287

(0.2)

5.37 d

Tb-155

Dy-156

4.7 E-6

288

(0.7)

22 m

Rh-107

Pd-108

3.8 E-3

288

(0.8)

1.73 h

Nd-149

Nd-150

2.0 E-2

288

(12)

41.3 d

Pm-148m

Sm-149

2.4 E-5

288

(2)

12.1 d

Ir-190

Ir-191

1.4 E-2

290

(0.8)

18 m

Se-81

Se-82

4.4 E-3

290

(0.6)

33 h

Sr-83

Sr-84

1.7 E-4

290

(0.03)

18.56 h

Gd-159

Gd-160

1.3 E-3

291

(4)

1.65 h

Ru-95

Ru-96

6.8 E - l

291

(?)

50 s

Rh-109m

Pd-110

?

291

(2)

3.85 d

Sb-127

Te-128

3.1 E-4

291

(0.8)

28 h

Pm-151

Sm-152

1.6 E-4

292

(0.2)

55 m

Cd-105

Cd-106

1.1 E-4

292

(4)

5 d

Ta-183

W-184

2.3 E-4

292

(3)

71 d

Re-183

Re-185, Os-184

8.7 E-4

293

(42)

33 h

Ce-143

Ce-142

8.9 E-5

294

(0.4)

3.1 h

Er-161

Er-162

8.4 E-4

Ir-193, Pt-195

2.8 E-3

294

(3)

19.4 h

Ir-194

294

(11)

39.5 h

Au-194

Au-197

8.4 E-3

295

(0.2)

39.35 d

Ru-103

Ru-104

3.4 E-4

(0.02)

17 d

Pd-103

Pd-104

6.0 E-4

295 295

(0.7)

1.73 h

Nd-149

Nd-150

1.9 E-2

295

(6)

12.1 d

Ir-190

Ir-191

4.2 E-2

295

(0.07)

9.59 h

Dy-155

Dy-156

1.1 E-5

296

(18)

8.47 h

Pd-101

Pd-102

1.5 E+l

296

(29)

7.5 h

Er-171

Er-170

6.9 E-3

296

(?)

115 d

Ta-182

W-183, Ta-181

·>

296

(29)

74 d

Ir-192

Ir-193

3.8 E-2

297

(94)

4.8 h

Ga-73

Ge-74

8.2 E - l

297

(4)

56 h

Br-77

Br-79

8.8 E-3

297

(34)

23.6 h

Hf-173

Hf-174

6.5 E-3

298

(48)

1.1 m

Ag-113m

Cd-114

8.6 E-4

298

(0.6)

36 a

Eu-150

Eu-151

8.4 E-7

298

(0.01)

75 m

Er-163

Er-164

5.3 6-4

298

(9)

5.37 h

299

(27)

72.1 d

Ag-113 Tb-160

Cd-114 Tb-159,, Dy-161

4.6 E-3 1.2 E-3

237

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν · I

299

(31)

299

(78)

9.5 d

Gd-149

Gd-152

8.3 E-6

(1.1 s )

Ho-163m

Er-164

300

?

(21)

78.3 h

Ga-67

Ga-69

4.1 E-2

300

(24)

17 h

Ce-135

Ce-136

8.9 E-3

301

(2)

1.65 h

Ru-95

Ru-96

3.4 E - l

301

(0.4)

1.73 h

Nd-149

Nd-150

1.0 E-2

301

(2)

11 h

Pt-189

Pt-190

1.9 E-3

303

(18)

10.5 a

Ba-133

Ba-134

2.0 E-5

303

(6)

22 m

Rh-107

Pd-108

3.6 E - l

304

(1)

120 d

Se-75

Se-76

1.3 E-4

304

(1)

56 h

Br-77

Br-79

2.2 E-3

304

(14)

4.48 h

Kr-85m

Rb-87

1.2 E-2

305

(?)

8.47 h

Pd-101

Pd-102

9

306

(0.9)

41.2 d

Ag-105

Ag-107, Cd-106

2.3 E-4

306

(5)

35.5 h

Kh-105

Pd-106

4.2 E-3

306

(0.06)

18.56 h

Gd-159

Gd-160

3.6 E-3

307

(6)

23.6 h

Hf-173

Hf-174

1.1 E-3

307

(89)

14 m

Tc-101

Ru-102, Mo-100

1.5 E - l

307

(87)

4.4 d

Rh-101m

Pd-102, Rh-103

7.7 E - l

307

(0.2)

3.4 m

Pr-140

Pr-141

3.8 E - l

307

(0.2)

28 h

Pm-151

Sm-152

4.0 E-5

308

(99)

23 h

Cr-48

Cr-50

4.0 E-4

308

(0.8)

55 m

Cd-105

Cd-106

4.5 E-4

308

(1)

120 d

Gd-151

Gd-152

3.4 E-6

308

(64)

7.5 h

Er-171

Er-170

1.5 E-2

308

(10)

30.7 d

Yb-169

Yb-170

2.8 E-2

308

(30)

74.2 d

Ir-192

Ir-193

3.9 E-2

309

(0.5)

39 m

Se-73m

Se-74

1.6 E-2

309

(0.9)

72.1 d

Tb-160

Tb-159, Dy-161

3.8 E-5

310

(0.3)

3.85 d

Sb-127

Te-128

4.5 E-5

310

(14)

(33 m)

Ho-159

Er-162

·>

311

(0.03)

13.46 h

Pd-109

Pd-110

1.2 E - l

311

(0.6)

1.73 h

Nd-149

Nd-150

1.5 E-2

311

(11)

23.6 h

Hf-173

Hf-174

2.1 E-3

312

(5)

22 m

Rh-107

Pd-108

2.7 E-2

312

(4)

41.3 d

Pm-148m

Sm-149

7.9 E-6

313

(7)

5 d

Ta-183

W-184

4.0 E-4

T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν " I

315

(17)

1.95 h

In-117m

Sn-118

8 . 0 E-3

315

(22)

12 m

Pr-147

Nd-148

·>

315

(23)

3.6 m

Gd-161

Gd-160

3 . 0 E-2

315

(2)

3.1 h

Er-161

Er-162

4 . 2 E-3

316

(1)

5.37 h

Ag-113

Cd-114

5 . 2 E-4

316

(100)

1.1 m

Ag-113m

Cd-114

1.8 E-3

316

(8)

19.5 m

Tb-163

Dy-164

2.9 E-2

316

(83)

74 d

Ir-192

Ir-193

1.1 E - l

317

(1)

4.3 d

Tc-96

Ru-98

2 . 6 E-6

318

(0.2)

9.59 h

Dy-155

Dy-156

3 . 0 E-5

318

(3)

32.06 h

Cs-129

Ba-130

4 . 0 E-4

318

(6)

165 d

Re-184m

Re-185

?

318

(2)

11 h

Pt-189

Pt-190

1.9 E-3

(1)

39 h

Ge-69

Ge-70, S e - 7 4

1.2 E-2

319

(5)

41.2 d

Ag-105

Ag-107,, Cd-106

1.3 E-3

319

(2)

10.98 d

Nd-147

Nd-148

1 . 1 E-3

319

(0.2)

6.7 d

Lu-172

Lu-175

1.9 E-5

319

(0.2)

70 d

Hf-175

Hf-176

6 . 4 E-5

319

(19)

35.5 h

Rh-105

Pd-106

1.6 E-2

320

(95)

5.8 m

Ti-51

V-51

w

320

(10)

27.7 d

Cr-51

C r - 5 2 , Fe-56

3.8 E-2

39 m

Se-73m

Se-74

9 . 6 E-2

319

320

(3)

320

(13)

3.8 h

Ir-195m

Pt-196

2 . 0 E-3

321

(0.6)

8.47 h

Pd-101

Pd-102

5.0 E-l

321

(3)

15.15 h

Eu-157

Gd-158

3 . 6 E-4

321

(24)

3.1 h

Ho-167

Er-168

2.8 E-2

321

(0.2)

6.71 d

Lu-177

Lu-176, Hf-178

1.9 E-5

322

(2)

22 m

Rh-107

Pd-108

1 . 1 E-2

322

(1)

30 h

Os-193

Os-192

9 . 8 E-5

324

(1)

28 h

Pm-151

Sm-152

2.0 E-4

324

(1)

6.7 d

Lu-172

Lu-175

9.7 E-5

325

(11)

2.9 d

Ru-97

Ru-98

4 . 1 E-2

Rh-101

Rh-103,, Pd-102

9 . 3 E-5

325

(11)

3 a

325

(94)

22.7 m

Lu-178m

Hf-179

3 . 3 E-2

326

(94)

2.2 h

Ta-178m

T a - 1 8 0 , W-180

2.2 E - l

326

(14)

4.8 h

Ga-73

Ge-74

1.2 E - l

326

(94)

8.1 h

Dy-157

Dy-158

3 . 4 E-2

239 T a b . 5 - 5 , continued

326

(94)

(4.3 s )

Hf-178m

Hf-179, T a - 1 8 0

Ν * I 1

326

(94)

31 a

Hf-178n

Hf-179

w

326

(0.05)

6.2 d

Au-196

Au-197

1.3 E-3

327

(62)

80 s

Rh-109

Pd-110

1.3 E - l

327

(5)

1.73 h

Nd-149

Nd-150

1.3 E - l

328

(4)

93.1 d

Eu-149

Eu-151

5.6 E-4

328

(1)

8.3 d

Ag-106m

Ag-107

4 . 2 E-4

328

(13)

19.4 h

Ir-194

I r - 1 9 3 , Pt-195

1.2 E-2

329

(19)

40.2 h

La-140

La-139

2.3 E-2

329

(93)

171 d

Ir-194m

Ir-193, Pt-195

5.0 E-3

329

(61)

39.5 h

Au-194

Au-197

4.6 E-2

330

(0.6)

6.7 d

Lu-172

Lu-175

5.8 E-5

331

(78)

9.4 h

Pb-201

Pb-204

w

332

(5)

41.2 d

Ag-105

Ag-107 , Cd-106

1.3 E-3

332

(12)

22.7 m

Lu-178m

Hf-179

4 . 1 E-3

332

(94)

5.5 h

Hf-180m

Ta-181, , Hf-180

2 . 5 E-2

332

(32)

2.2 h

Ta-178m

Ta-180, , W-180

1.4

333

(0.03)

4.4 d

Kh-101m

Pd-102,, Rh-103

2.7 E-4

333

(23)

6.2 d

Au-196

Au-197

5.9 E - l

334

(94)

36 a

Eu-150

Eu-151

1.3 E-4

334

(4)

12.6 h

Eu-150m

Eu-151

2.4 E - l

336

(70)

1.65 h

Ru-95

Ru-96

1.2 E+l

E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

336

(46)

4.5 h

In-115m

Sn-116, , In-115

8 . 3 E-2

336

(0.8)

15.15 h

Eu-157

Gd-158

9.6 E-5

337

(0.4)

72.1 d

Tb-160

Tb-159 , Dy-161

1.7 E-5

339

(5)

19.5 m

Tb-163

Dy-164

1.8 E-2

339

(55)

171 d

Ir-194m

I r - 1 9 3 , Pt-195

3 . 0 E-3

340

( 0 . 0 0 4 ) 270 d

Co-57

Ni-58, Co-59

2.4 E-6

340

(22)

28 h

Pm-151

Sm-152

4 . 4 E-3

341

(47)

13 d

Cs-136

Ba-137

5.2 E-4

341

(1)

5.32 d

Tb-155

Dy-156

2 . 1 E-5

342

(5)

7.5 d

Ag-111

Cd-112

3 . 0 E-3

343

(0.04)

69.6 m

Te-129

Te-130

7.6 E-3

343

(0.03)

17.7 m

Yb-167

Yb-168

2.7 E-4

343

(87)

70 d

Hf-175

Hf-176

2.8 E-2

344

(27)

12.4 a

Eu-152

Eu-153

2.2 E-4

344

(2)

9.3 h

Eu-152m

Eu-153

1.5 E-2

240 T a b . 5-5, continued

E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I 7.0 E-4

344

(24)

6.24 d

Bi-206

Bi-209

345

(42)

41.2 d

Ag-105

Ag-107 , Cd-106

1.1 E-2

346

(13)

42.4 d

Hf-181

Hf-180

4.7 E-5

346

(11)

81 m

Pt-197m

Pt-198

3.0 E - l

347

(25)

9.5 d

Gd-149

Gd-152

6.8 E-6

347

(4)

55 m

Cd-105

Cd-106

2.2 E-3

347

(57)

3.1 h

Ho-167

Er-168

6.9 E-2

348

(2)

22 m

Rh-107

Pd-108

1.1 E-2

348

(0.2)

18.56 h

Gd-159

Gd-160

8.8 E-3

348

(6)

19.5 m

Tb-163

Dy-164

2.2 E-2

348

(0.3)

93.1 d

Tm-168

Tm-169

5.1 E-4

349

(2)

1.73 h

Nd-149

Nd-150

5.2 E-2

350

(1)

23.4 h

Nb-96

Mo-97

7.7 E-4

350

(0.3)

93.1 d

Eu-149

Eu-151

4.2 E-5

350

(0.02)

72.1 d

Tb-160

Tb-159 , Dy-161

8.6 E-7

351

(26)

19.5 m

Tb-163

Dy-164

9.4 E-2

351

(0.2)

1.37 a

Lu-173

Lu-175,, Hf-175

1.3 E-5

2.8 d

351

(3)

Pt-191

Pt-192

1.5 E-3

352

(0.003) 270 d

Co-57

Ni-58, Co-59

6.5 E-2

352

(10)

2.6 m

Nb-99

Mo-100

1.9 E-2

352

(0.2)

6.7 d

Lu-172

Lu-175

1.9 E-5

353

(0.02)

83 m

Ge-75

Ge-76, Se-80

3.8 E-3

354

(0.2)

70 d

Hf-175

Hf-176

6.4 E-5

354

(11)

5 d

Ta-183

W-184

6.3 E-4

355

(0.3)

8.47 h

Pd-101

Pd-102

2.5 E - l

355

(0.6)

14 h

Os-183

Os-184

1.6 E-5

355

(0.9)

54 m

In-116ml

In-115, Sn-117

8.2 E-2

356

(?)

36 h

Ni-57

Ni-58

7 6.8 E-5

356

(62)

10.5 a

Ba-133

Ba-134

356

(13)

5.35 d

Tb-156

Tb-159

1.5 E-4

356

(88)

6.18 d

Au-196

Au-197

2.3

357

(0.02)

17 d

Pd-103

Pd-104

6.0 E-4

358

(0.4)

22 m

Rh-107

Pd-108

2.3 E-3

358

(0.1)

6.7 d

Lu-172

Lu-175

1.0 E-5

359

(3)

4.32 h

Sb-129

Te-130

1.0 E-3

359

(6)

3.8 h

Ir-195

Pt-196

9.0 E-4

360

(?)

2.1 m

Ga-75

Ge-76

?

241

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν

-

I

356

(?)

36 h

Ni-57

Ni-58

?

356

(62)

10.5 a

Ba-133

Ba-134

6.8 E-5

356

(13)

5.35 d

Tb-156

Tb-159

1.5 E-4

356

(88)

6.18 d

Au-196

Au-197

2.3

357

(0.02)

17 d

Pd-103

Pd-104

6.0 E-4

358

(0.4)

22 m

Rh-107

Pd-108

2.3 E-3

358

(0.1)

6.7 d

Lu-172

Lu-175

1.0 E-5

359

(3)

4.32 h

Sb-129

Te-130

1.0 E-3

359

(6)

3.8 h

Ir-195

Pt-196

9.0 E-4

360

(?)

2.1 m

Ga-75

Ge-76

?

360

(6)

2.8 d

Pt-191

Pt-192

3.2 E-3

360

(0.1)

9.35 h

Te-127

Te-128

1.1 E-2

361

(61)

3.6 m

Gd-161

Gd-160

6.1 E-2

361

(100)

7.1 h

Se-73

Se-74

1.5 E - l

361

(99)

9.9 m

0s-190m

Os-192

1.8 E-2

361

(13)

12.1 d

Ir-190

Ir-191

9.3 E-2

361

(91)

3.1 h

Ir-190m

Ir-191

2.6

362

(0.8)

2.35 h

Dy-165

Dy-164

8.7 E-3

362

(0.5)

1.3 m

Dy-165m

Dy-164

5.5 E-3

363

(0.07)

6.47 d

Cs-132

Cs-133

1.7 E-3

363

(40)

25 d

Hf-179n

Hf-180

·>

363

(10)

18.56 h

Gd-159

Gd-160

4.4 E - l

364

(13)

15.2 m

Tm-175

Yb-176

3.9 E-2

365

(1)

8.2 m

As-79

Se-80

1.3 E-2

365

(13)

3.8 h

Ir-195m

Pt-196

2.0 E-3

366

(1)

66 h

Mo-99

Mo-100

3.1 E-3

366

(0.5)

5 d

Ta-183

W-184

2.9 E-5

367

(12)

11.3 h

Ge-77

Se-82

2.9 E-5

367

(79)

51.8 m

Ru-94

Ru-96

?

367

(2)

22 m

Rh-107

Pd-108

1.2 E-2

367

(0.8)

1.73 h

Nd-140

Nd-150

2.1 E-2

367

(2)

5.32 d

Tb-155

Dy-156

4.2 E-5

368

(21)

48.4 m

Au-200

Hg-201

6.7 E-3

368

(83)

18.7 h

Au-200m

Hg-201

4.3 E-6

368

(88)

26.1 h

Tl-200

Tl-203

7.4 E-5

371

(2)

14.6 h

Nb-90

Mo-92

7.6 E-4

371

(0.4)

20 h

Rh-100

Pd-102

1.0 E-4

242 T a b . 5-5, continued Ε, keV' (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I 9.5 E-5

371

(0.04)

3.1 h

Er-161

Er-162

371

(23)

12.1 d

Ir-190

Ir-121

1.6 E - l

372

(3)

23.4 h

Nb-96

Mo-9 7

2.3 E-3

372

(0.2)

35.3 m

Sn-11

Sn-112

2.8 E-3

372

(32)

32.06 h

Cs-129

Ba-130

4 . 1 E-3

372

(0.3)

7.5 h

Er-171

Er-170

7.2 E-5

373

(100)

22.2 h

K-43

Ca-44

4 . 0 E-2

373

(13)

11.5 d

Ba-131

Ba-132

2.0 E-4

373

(11)

15.15 h

Eu-157

Gd-158

1.3 E-3

373

(3)

6.7 d

Lu-172

Lu-175

2.8 E-4

374

(2)

3.3 h

Cu-61

Cu-63

2.4 E-2

374

(0.02)

5.37 h

Ag-113m

Cd-114

3.6 E-7

374

(0.7)

74 d

Ir-192

Ir-193

1.0 E-2

374

(12)

42.6 m

Hg-199m

Hg-200

6.3 E - l

374

(90)

66.9 m

Pb-204m

Pb-206

3.4 E-2

374

(0.3)

8.3 d

Ag-106m

Ag-107

1.2 E-4

Tb-163

Dy-164

2.2 E-3

19.5 m

376

(0.6)

377

(0.09)

3.1 h

Er-161

Er-162

1.9 E-4

377

(32)

8.51 m

Fe-53

F e - 5 4 , Ni-58

8.2 E - l

378

(3)

6.7 d

Lu-172

Lu-175

2.9 E-4

379

(0.3)

4.8 h

Ga-73

Ge-74

2.6 E-3

379

(28)

161 d

Lu-177m

Hf-178, Lu-176

1.8 E-4

380

(1)

17 h

Ce-135

Ce-136

3.7 E-4

380

(0.9)

28 h

Pm-151

Sm-152

1.8 E-4

380

(2)

12.1 d

Ir-190

Ir-191

1.4 E-2

381

(24)

33 h

Sr-83

Sr-84

6.7 E-3

381

(77)

13 h

Y-87m

Y-89

1.0 E - l

381

(0.04)

8,47 h

Pd-101

Pd-102

3 . 3 E-2

381

(0.04)

40.1 m

Sn-123m

Sn-124

2.4 E-3

382

(20)

33 h

Sr-83

Sr-84

5.6 E-3

382

(0.7)

22 m

Rh-107

Pd-108

3.9 E-3

382

(86)

14 h

Os-183

Os-184

2.3 E-3

382

(7)

10.2 d

Pt-188

Pt-190

2.6 E-4

383

(0.2)

9.59 h

Dy-155

Dy-156

3 . 1 E-5

385

(1)

56 h

Br-77

Br-79

2 . 3 E-3

385

(0.4)

1.73 h

Nd-149

Nd-150

1.0 E-2

386

(92)

3.9 h

Zn-71

Ge-76

1.2 E-2

243 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

386

(5)

19.5 m

Tb-163

Dy-164

1.8 E-2

386

(3)

3.1 h

Ho-167

Er-168

3.6 E-3

386

(0.5)

6.24 d

Bi-206

Bi-209

1 . 5 E-5 1.0 E-4

387

(1)

30 h

Os-193

Os-192

388

(0.6)

17 h

Ce-135

Ce-136

2.3 E-4

388

(79)

2.81 h

Sr-87m

Sr-88

3.4 E + l

388

(w)

80.3 h

Y-87

Y-89

w

388

(3)

40 h

Hg-195m

Hg-196

6.9 E-5 3.9 E - l

389

(35)

13 d

1-126

1-127

389

(2)

33 h

Sr-83

Sr-84

5 . 5 E-4

390

(24)

19.5 m

Tb-163

Dy-164

8.6 E-2

390

(4)

2.4 m

Zn-71

Ge-76

7 . 3 E-3

390

(13)

59.6 s

Na-25

Mg-26

4.7 E - l

391

(4)

8.3 d

Ag-106m

Ag-107

1.7 E-3

391

(35)

171 d

Ir-194m

Ir-193, Pt-195

1.9 E-3

392

(60)

1.1 m

Ag-113m

Cd-114

1.1 E-3

392

(9)

22 m

Rh-107

Pd-108

4.9 E-2

392

(64)

115.1 d

Sn-113

Sn-114

9.6 E-4

392

(13)

2.13 h

Ba-129m

Ba-130

2.7 E-3

392

(1)

72.1 d

Tb-160

T b - 1 5 9 , Dy-161

4.3 E-5

393

(64)

99.48 m

In-113m

In-115, Sn-114

1.3

393

(0.1)

14 m

Tc-101

Ru-102, Mo-100

1.6 E-4

393

(5)

39 m

Se-73m

Se-74

1.6 E - l

394

(97)

83.4 d

Zr-88

Zr-90

1.5 E - 3

394

(2)

9.13 h

Zn-62

Zn-64

1.6 E-3

394

(7)

78.3 h

Ga-67

Ga-69

1.3 E-2

395

(7)

12.1 d

Ir-190

Ir-191

5 . 0 E-2

396

(6)

4.2 d

Yb-175

Yb-176, Lu-176

6.6 E-2

397

(12)

22.2 h

K-43

Ca-44

4 . 8 E-3

397

(0.2)

14 h

Os-183

Os-184

5 . 5 E-6

398

(0.1)

40.2 h

La-140

La-139

1.2 E - 5

398

(0.5)

17 h

Ce-135

Ce-136

1.8 E-4

398

(0.8)

10.98 d

Nd-147

Nd-148

9

398

(11)

6.24 d

Bi-206

Bi-209

3 . 1 E-4

399

(0.1)

20 h

Rh-100

Pd-102

2.6 E - 5

399

(88)

8.2 h

Tm-173

Yb-174

3.9 E - l

400

(0.5)

6.7 d

Lu-172

Lu-175

4.8 E-5

244 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

401

(0.5)

10 h

Os-183m

Os-184

401

(38)

21.1 h

Mg-28

Si-30

5.0 E-5 ?

401

(12)

120 d

Se-75

Se-76

1.6 E-3

401

(4)

52.1 h

Pb-203

Pb-204

5.6 E - 3

402

(4)

39 m

Se-73m

Se-74

1.3 E - l

402

(2)

19.5 m

Tb-163

Dy-164

6.8 E-3

402

(?)

12.1 d

Ir-190

Ir-191

?

403

(0.03)

26.4 h

As-76

A s - 7 5 , Se-77

3.9 E-5

403

(4)

3.1 h

Ho-167

Er-168

4.8 E-3

404

(0.2)

9.59 h

Dy-155

Dy-156

3 . 1 E-5

404

(0.03)

15 h

Os-183

Os-184

8 . 2 E-7 8 . 8 E-4

404

(0.9)

11 h

Pt-189

Pt-190

405

(6)

29.7 m

Nd-139

Nd-142

1.4 E-5

406

(12)

2.2 h

Rh-106m

Pd-108

7.9 E-2

406

(13)

8.3 d

Ag.106m

Ag-107

5 . 5 E-3

406

(3)

12.6 h

Eu-150m

Eu-151

1.8 E - l

407

(0.5)

5 d

Ta-183

VV-184

2.8 E-5

407

(28)

12.1 d

Ir-190

Ir-191

2.0 E - l

409

(8)

2.8 d

Pt-191

Pt-192

4.3 E-3

410

(0.1)

10.98 d

Nd-147

Nd-148

5.5 E-5

410

(2)

6.7 d

Lu-172

Lu-175

2.0 E-4

411

(0.1)

3.12 h

Ag-112

Cd-113

1.6 E-5

411

(23)

32.06 h

Cs-129

Ba-130

2.9 E-3

412

(4)

3.85 d

Sb-127

Te-128

6.1 E-4

412

(96)

2.695 d

Au-198

Au-197, Hg-199

8.4 E-2

413

(17)

15.15 h

Eu-157

Gd-158

2.0 E - 3

414

(18)

41.3 d

Pm-148m

Sm-149

3.6 E-5

414

(19)

54 d

Eu-148

Eu-151

8.2 E-5

415

(0.02)

13.46 h

Pd-109

Pd-110

8.0 E-2

415

(88)

12.4 d

Sb-126

Te-128

7.5 E - 6

415

(5)

19.5 m

Tb-163

Dy-164

1.8 E-2

416

(24)

11.3 h

Ge-77

Se-82

5 . 8 E-5

416

(0.7)

74 d

Ir-192

Ir-193

3.1 E-4

417

(32)

54 m

In-116ml

In-115, Sn-117

2.9

418

(0.02)

4.4 d

Rh-101m

Pd-102, Rh-103

1.8 E-4

418

(1)

9.35 h

Te-127

Te-128

1.1 E - l

418

(7)

33 h

Sr-83

Sr-84

2.0 E-3

245 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

419

(9)

2.9 a

Rh-102

Rh-103,, Pd-104

7.7 E-5

419

(0.06)

39 h

Ge-69

Ge-70, S e - 7 4

7.2 E - 4

419

(0.3)

83 m

Ge-75

Ge-76, S e - 8 0

5.7 E - 2

419

(0.1)

206 d

Rh-102

Rh-103, , Pd-104

4.6 E-5

419

(0.3)

8.3 d

Ag-106m

Ag-107

1.3 E-4

419

(20)

161 d

Lu-177m

Hf-178, Lu-176

1.3 E-4

420

(25)

2.13 h

Ba-129m

Ba-130

5.3 E-3

420

(0.08)

7.5 h

Er-171

Er-170

1.9 E-5

422

(11)

19.5 m

Tb-163

Dy-164

3.9 E-2

422

(0.3)

3.1 h

Er-161

Er-162

6 . 3 E-4

422

(0.3)

93.1 d

Tm-168

Tm-169

5.1 E-4

422

(86)

3.62 h

Pb-202m

Pb-204

2 . 3 E-4

424

(2)

33 h

Sr-83

Sr-84

5.6 E-4

424

(11)

1.73 h

Nd-149

Nd-150

2.8 E - l

424

(5)

10.2 d

Pt-188

Pt-190

1.9 E-4

426

(94)

22.7 m

Lu-178m

Hf-179

3.2 E-2

426

(80)

( 4 . 3 s)

Hf-178m

Hf-179, T a - 1 8 0

?

426

(97)

31 a

Hf-178n

Hf-179

w

426

(7)

6.2 d

Au-196

Au-197

1.8 E - l

426

(100)

2.2 h

Ta-178m

T a - 1 8 0 , W-180

2.2 E - l

427

(0.1)

8.47 h

Pd-101

Pd-102

8 . 4 E-2

4 28

(30)

2.77 a

sb-125

Te-126

2.3 E-5

428

(4)

19.5 m

Tb-163

Dy-164

1.5 E - 2

4 29

(13)

2.2 h

Rh-106m

Pd-108

8.5 E-2

430

(13)

8.3 d

Ag-106m

Ag-107

5.5 E - 3

430

(0.1)

3.1 h

Ho-167

Er-168

1.2 E - 4

432

(2)

8.2 m

As-79

Se-80

2.5 E-2

432

(40)

22.6 m

Sm-141m

Sm-144

w

432

(1)

6.7 d

Lu-172

Lu-175

9.4 E-5

432

(3)

12.1 d

Ir-190

Ir-191

2.2 E - 2

433

(3)

45 m

Cd-105

Cd-106

1.7 E - 3

433

(3)

40.2 h

La-140

La-139

3.6 E-4

433

(6)

41.3 d

Pm-148m

Sm-149

1.2 E - 5

433

(3)

54 d

Eu-148

Eu-151

1.3 E-5

433

(0.6)

9.59 h

Dy-155

Dy-156

9 . 0 E-5

4 33

(1)

70 d

Hf-175

Hf-176

3.2 E-4

433

(13)

3.8 h

Ir-195m

Pt-196

2.0 E-3

Tab. 5-5, E.keV

continued

(1%)

Τ

Nuclide

T a r g e t Nuclide

Ν " I

434

(43)

16.8 s

Rh-108

Pd-110

w

434

(91)

5.9 m

Rh-108m

Pd-110

w

434

(0.5)

2.1 m

Ag-108

Ag-109,

434

(91)

127 a

Ag-108m

Ag-109

434

(0.2)

15.2 d

Eu-156

Gd-157

1.9 E-6

435

(0.5)

23.4 h

Nb-96

Mo-9 7

3.9 E-4

Cd-110

2.4 1.4 E-5

435

(0.07)

8.47 h

Pd-101

Pd-102

5.9 E-2

435

(1)

2.13 h

Ba-129m

Ba-130

2.1 E-4 3.6 E-3

435

(1)

19.5 m

Tb-163

Dy-164

436

(0.3)

9 h

Ce-137

Ce-138

1.9 E-4

436

(0.03)

75 m

Er-163

Er-164

1.6 E-3

438

(0.9)

33 h

Sr-83

Sr-84

439

(100)

13.9 h

Zn-69m

Zn-70, Ge-71,

439

(79)

36 a

Eu-150

Eu-151

4.1 E-4

439

(91)

12.2 d

T-202

Tl-203

3.9 E - l

440

(9)

12 s

Mg-23

Mg-24

1.0

440

(2)

56 h

Br-77

Br-79

4.4 E-3

440

(1)

10.98 d

Nd-147

Nd-148

5.4 E-4

440

(0.03)

75 m

Er-163

Er-164

1.6 E-3

440

(0.1)

9.5 h

Hg-195

Hg-196

7.7 E-5

441

(1)

28 h

Pm-151

Sm-152

2.0 E-4

Tb-163

Dy-164

3.2 E-3

2.5 E-4 Ga-73

4.1 E-2

441

(0.9)

19.5 m

443

(12)

41.2 d

Ag-105

Ag-107,

443

(16)

25 m

1-128

1-127

5.9 E - l 9

Cd-106

3.1 E-3

443

(26)

( 3 . 8 m)

Cs-128

Ba-130

443

(85)

5.5 h

Hf-180m

Tal81,

444

(2)

69.2 h

Ag-104

Cd-106

444

(0.3)

39.35 d

Ru-103

Ru-104

5.1 E-4

444

(2)

1.73 h

Nd-149

Nd-150

5.3 E-2

445

(6)

5.7 h

Mo-90

Mo-92

9.0 E-4

445

(4)

3.85 d

Sb-127

Te-128

6.0 E-4

446

(12)

20 h

Rh-100

Pd-102

2.6 E-3

446

(6)

4.4 m

In-118m

Sn-119

2.7 E-4

Hf-180

2.3 E-2 1.8 E-5

446

(4)

28 h

Pm-151

Sm-152

8.0 E-3

447

(2)

9 h

Ce-137

Ce-138

1.3 E-3

447

(0.1)

8.2 m

As-79

Se-80

1.9 E-3

447

(0.4)

3.1 h

Er-161

Er-162

8.4 E-4

247 T a b . 5 - 5 , continued E.keV ' (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

447

(22)

93.1 d

Tm-168

Tm-169

3.8 E-2

448

(3)

12.1 d

Ir-190

Ir-191

2 . 1 E-2

451

(24)

2.2 h

Rh-106m

Pd-108

1.6 E - l

451

(28)

8.3 d

Ag-106m

Ag-107

1.2 E-2

452

(0.5)

22 m

Rh-107

Pd-108

2.7 E - 3

452

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E-5

452

(0.2)

40 h

hg-195m

Hg-196

4.6 E-6

453

(0.07)

16.98 h

Re-188

Re-187, Os-189

4 . 1 E-4

453

(1)

15.15 h

Eu-157

Gd-158

1.2 E-4

453

(0.1)

6.24 d

Bi-206

Bi-209

453

(65)

24 d

Hf-179n

Hf-180

2.9 E-6 9

454

(0.6)

8.47 h

Pd-101

Pd-102

5.0 E - l

454

(63)

5.53 a

Pm-146

Sm-147

1.4 E-5

455

(0.3)

22.1 h

Os-182

Os-184

3.9 E-7

456

(0.08)

206 d

Rh-102

Rh-103, Pd-104

3.6 E-5

456

(3)

2.8 d

Pt-191

Pt-192

1.5 E - 3

457

(0.02)

26.4 h

As-76

As-75, Se-77

2.6 E-5

457

(0.08)

1.37 a

Lu-173

Lu-175, Hf-174

7.8 E - 6

458

(0.2)

35.3 m

Sn-111

Sn-112

2.8 E - 3

459

(0.1)

9.59 h

Dy-155

Dy-156

1.5 E-5

460

(28)

23.4 h

Nb-96

Mo-97

2.2 E - 2

460

(7)

69.6 m

Te-129

Te-130

1.4 2.9 E-3

460

(14)

2.13 h

Ba-129m

Ba-130

460

(2)

3.1 h

Ho-167

Er-169

2.3 E - 3

461

(4)

30 h

Os-193

Os-192

3.9 E-4

462

(3)

19.5 m

Tb-163

Dy-164

1 . 1 E-2

462

(?)

12.1 d

Ir-190

Ir-191

•>

463

(0.05)

6.24 d

Bi-206

Bi-209

1.5 E - 6

463

(0.9)

54 m

In-116ml

In-115, Sn-117

464

(32)

21 m

Rb-84m

Rb-85, Sr-86,

464

(11)

2.77 a

Sb-125

Te-126

8.7 E-6

464

(0.7)

15.15 h

Eu-157

Gd-158

8.4 E-5

465

(2)

6.47 d

Cs-132

Cs-133

4.8 E-2

465

(8)

8.2 h

Tm-173

Yb-174

3.5 E-2

466

(0.1)

20 h

Rh-100

Pd-102

2.6 E-5

467

(0.3)

40 h

Hg-195m

Hg-196

6.9 E-6

468

(3)

2.13 h

Ba-129m

Ba-130

6.3 E-4

8 . 2 E-2 Y-89

1.5 E+2

248

T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

468

(0.2)

3.1 h

Er-161

Er-162

4 . 2 E-4

468

(48)

74 d

Ir-192

Ir-193

6 . 3 E-2

469

(0.2)

83 m

Ge-75

Ge-76, S e - 8 0

3 . 8 E-2

469

(18)

4.44 h

Ru-105

Ru-104

3.6 E-3

469

(3)

206 d

Rh-102

Rh-103, , P d - 1 0 4

1.4 E - 3

470

(1)

16.8 d

Te-121

Te-122

2.1 E-4

471

(0.1)

22 m

Rh-107

Pd-108

5.5 E - 4

472

(1)

5.7 h

Mo-90

Mo-9 2

1.5 E-4 3.8 E-3

473

(25)

3.85 d

Sb-127

Te-128

474

(0.9)

8.3 d

Ag-106m

Ag-107

3 . 8 E-4

475

(85)

4.3 m

Tc-102m

Ru-104

w

475

(46)

206 d

Rh-102

R h - 1 0 3 , , Pd-104

2 . 2 E-2

475

(95)

2.9 a

Rh-102m

Rh-103, , P d - 1 0 4

8.1 E-4

475

(3)

19.5 m

Tb-163

Dy-164

1 . 1 E-2

476

(0.2)

8.2 m

As-79

Se-80

2.6 E-3

476

(2)

42.4 d

Hf-181

Hf-180

7.2 E-6

477

(2)

15.15 h

Eu-157

Gd-158

2.4 E - 4

477

(0.3)

14 h

Os-183

Os-184

8.2 E-6

478

(10)

53.4 d

Be-7

Be-9,

478

(1)

16.8 h

Re-188

Re-187, Os-189

5.9 E - 3

478

(15)

41.5 h

Ir-188

Ir-191, Pt-190

1.2 E - 4

478

(2)

•12,1 d

Ir-190

Ir-191

1.5 E-2

C-12

1.7 E - 4

479

(21)

23.8 h

VV—187

VV-186

2 . 3 E-2

480

(?)

1.73 h

Nd-149

Nd-150

?

480

(0.1)

3.1 h

Ho-167

Er-168

1.2 E - 4

480

(32)

6.1 d

Ni-56

Ni-58

6.7 E - 4

480

(0.09)

6.24 d

Bi-206

Bi-209

2 . 6 E-6

480

(91)

3.19 h

Y-90m

Zr-93

1.1 E-l

481

(6)

23.4 h

Nb-96

Mo-97

4.6 E-3

481

(2)

19.4 h

La-135

Ce-136, La-138

7.2 E - 4

481

(4)

3.8 h

Ir-195m

Pt-196

6.0 E-4

482

(8)

2.13 h

Ba-129m

Ba-130

1.7 E - 3

482

(0.7)

6.7 d

Lu-172

Lu-175

6 . 8 E-5

482

(81)

42.4 d

Hf-181

Hf-180

2.9 E-4

483

(97)

171 d

Ir-194m

Ir-193, Pt-195

5.2 E - 3

483

(1)

39.5 h

Au-194

Au-197

7.6 E-4

484

(2)

17 h

Ce-135

Ce-136

7 . 4 E-4

249 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

484

(1)

9.59 h

Dy-155

Dy-156

1.5 E-4

485

(0.7)

12.1 d

Ir-190

Ir-191

5.0 E-3

485

(1)

56 h

Br-77

Br-79

2.2 E-3

485

(91)

80.3 h

Y-87

Y-89

8.7 E-2

485

(2)

10 h

Os-183m

Os-184

2 . 0 E-4

485

(3)

74 d

Ir-192

Ir-193

3 . 9 E-3

486

(0.08)

16.98 h

Re-188

Re-187, Os-189

4 . 7 E-4

486

(0.09)

72.1 d

Tb-160

T b - 1 5 9 , Dy-161

3 . 9 E-5

Lu-175

6.9 E-5

486

(0.7)

6.7 d

Lu-172

487

(62)

3.9 h

Zn-71m

Ge-76

8 . 1 E-3

487

(1)

69.6 m

Te-129

Te-130

1.9 E - l

487

(2)

11.5 d

Ba-131

Ba-132

3.0 E-5

487

(45)

40.2 d

La-140

La-139

5.4 E-3

487

(1)

19.5 m

Tb-163

Dy-164

3.6 E-3

488

(0.2)

4.8 h

Ga-73

Ge-74

1.7 E-3

489

(7)

4.54 d

Ca-47

Ca-48

2.6 E-4

489

(0.1)

10.98 d

Nd-147

Nd-148

5.4 E-5

489

(0.06)

3.1 h

Er-161

Er-162

1.3 E-4

489

(4)

74 d

Ir-192

Ir-193

5.2 E-3

490

(0.2)

39 m

Se-73m

Se-74

6.4 E-3

490

(0.2)

15.2 h

Eu-156

Gd-157

1.8 E-6

490

(2)

4.7 d

Lu-172

Lu-175

1.9 E-4 3.3 E-2

491

(3)

13 d

1-126

1-127

491

(0.8)

12.1 d

Ir-190

Ir-191

5.7 E-3

492

(15)

53.38 h

Cd-115

Cd-116

9 . 3 E-2 ·>

492

( 0 . 0 0 3 ) 340 d

Sm-145

Sm-147

494

(?)

1.73 h

Nd-149

Nd-150

7.8 E-3

495

(23)

19.5 m

Tb-163

Dy-164

8.2 E-2

495

(69)

31 a

Hf-178n

Hf-179

w

496

(0.03)

8.47 h

Pd-101

Pd-102

2.6 E-2

496

(42)

11.5 d

Ba-131

Ba-132

6.3 E-4

496

(0.6)

14 h

Os-183

Os-184

1.6 E-5

497

(86)

39.35 d

Ru-103

Ru-104

1.4 E - l

497

(0.04)

17 d

Pd-103

Pd-104

1.2 E-3

497

(15)

6.24 d

Bi-206

Bi-209

4.4 E-4

498

(20)

1.6 m

Sb-124m

Te-125

w

498

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E-3

T a b . 5 - 5 , continued Ε, keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

498

(82)

18.7 h

Au-200m

Hg-201

4.2 E-6

499

(1)

9.59 h

Dy-155

Dy-156

1.5 E - 4

501

(7)

41.3 d

Pm-148m

Sm-149

1.4 E - 5 3.2 E - 3

501

(12)

5.5 h

Hf-180m

T a - 1 8 1 , Hf-180

503

(94)

9.9 m

0s-190m

Os-192

1.7 E-2

503

(1)

12.1 d

Ir-190

Ir-191

7.0 E - 3

503

(94)

3.1 h

Ir-190m

Ir-191

2.7

506

(0.8)

6.47 d

Cs-132

Cs-133

1.9 E-2

506

(5)

36 a

Eu-150

Eu-151

7.0 E-6

508

(18)

16.8 d

Te-121

Te-122

3.8 E - 3

516

(2)

1.3 m

Dy-165m

Dy-164

2.2 E - 2

516

(41)

6.24 d

Bi-206

Bi-209

1.2 E - 3

518

(14)

17 h

Ce-135

Ce-136

5.2 E - 3

518

(34)

12.1 d

Ir-190

Ir-191

2.4 E - l

519

(1)

20 h

Rh-100

Pd-102

2.7 E - 4

520

(0.1)

12.2 d

Tl-202

Tl-203

4 . 3 E-4 5 . 3 E-2

520

(24)

56 h

Br-77

Br-78

521

(46)

86.2 d

Rb-83

Rb-85, Sr-84

2.9 E-3

521

(0.4)

38.8 h

As-77

Se-78, Br-81

3 . 4 E-4

521

(0.2)

18.7 m

Eu-159

Gd-160

8.3 E-4

521

(0.04)

6.2 d

Au-196

Au-197

1.0 E - 3

524 c 97

(91)

1.7 m

Sc-50

Ti-50

w

(2)

25 m

1-128

1-127

7.4 E-2

527

(0.7)

26.4 m

Au-201

Hg-202

5.0 E-3

528

(50)

53.38 h

Cd-115

Cd-116

3.1 E - l

528

(2)

2.13 h

Ba-129

Ba-130

4.2 E-4

528

(0.4)

3.1 h

Er-161

Er-162

8.4 E-4

528

(4)

6.7 d

Lu-172

Lu-175

3.9 E - 4

529

(0.06)

66 h

Mo-9 9

Mo-100

1.9 E-4

529

(0.5)

93.1 d

Eu-149

Eu-151

7.0 E-5

529

(2)

39.5 h

Au-194

Au-197

1.5 E - 3

529

(31)

86.2 d

Rb-83

Rb-85, Sr-84

1.9 E-3

2.4 h

Br-83

Rb-87

2.3 E-3

530

(1)

530

(1)

3.6 m

Gd-161

Gd-160

5.0 E - 3

531

(0.1)

4.54 d

Ca-47

Ca-48

3.7 E - 6

531

(0.9)

14 m

Tc-101

Ru-102, Mo-100

1.5 E - 3

531

(12)

10.98 d

Nd-147

Nd-148

6.5 E-3

251

Tab.

5 - 5 , continued

Ε, k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν

' I

531

(0.06)

46.75 h

Sm-153

Sm-154

2.6 E-3

532

(0.3)

39 h

Ge-69

Ge-70, Se-74

3.6 E-2

532

(0.09)

69.6 m

Te-129

Te-130

1.7 E-2

532

(1)

9.25 d

Tm-167

Tm-169 ,

533

(10)

19.5 m

Tb-163

Dy-164

3.6 E-2

534

(66)

5.35 d

Tb-156

Tb-159

7.9 E-4

535

(3)

2.13 h

Ba-129m

Ba-130

6.3 E - 4

536

(0.05)

93.1 d

Eu-149

Eu-151

7.0 E - 6

536

(0.7)

6.7 d

Lu-172

Lu-175

6.8 E-5

537

(87)

7.6 m

In-lllm

In-113, Sn-112

4.2 E-7

537

(0.1)

35.3 m

Sn-111

Sn-112

1.4 E - 3

537

( 0 . 0 0 1 ) 18.56 h

Gd-159

Gd-160

4.4 E-5

537

(31)

6.24 d

Bi-206

Bi-209

9.0 E - 4

538

(0.03)

18 m

Se-81

Se-82

1.6 E-4

538

(0.7)

55 m

Cd-105

Cd-106

3.9 E-4

539

(0.3)

38 d

Re-184

Re-185

6.0 E - 4

Yb-168

3.5 E-3

539

(14)

2.8 d

Pt-191

Pt-192

7.4 E-3

540

(7)

15.8 s

Tc-100

Ru-101

3.1 E - l

540

(78)

20 h

Rh-100

Pd-102

2.0 E-2

540

(1)

6.7 d

Lu-172

Lu-175

9.9 E-5

541

(9)

1.73 h

Nd-149

Nd-150

2.4 E - l

542

(0.1)

4.8 h

Ga-73

Ge-74

8.6 E-4

543

(3)

3.85 d

Sb-127

Te-128

4.5 E-4

543

(15)

2.13 h

Ba-129m

Ba-130

8.4 E-4

543

(15)

30.8 m

Pt-199

Pt-198

w

545

(19)

4.23 h

Sb-129

Te-130

6.2 E-3

545

(6)

14 m

Tc-101

Ru-102,, Mo-100

9.6 E-3

545

(4)

4.4 d

Rh-101

Pd-102,

3.5 E-2

545

(2)

19.5 m

Tb-163

Dy-164

7.2 E-3

545

(4)

11 h

Pt-189

Pt-190

3.9 E-3

546

(0.7)

17 h

Ce-135

Ce-136

6.5 E-2

546

(0.2)

2.35 h

Dy-165

Dy-164

1.9 E-3

547

(11)

2.13 h

Ba-129m

Ba-130

2.3 E-3

Rh-103

547

(2)

93.1 d

Tm-168

Tm-169

3.4 E-3

548

(14)

9.13 h

Zn-62

Zn-64

1.1 E-2

549

(0.05)

74 m

Nb-97

Mo-98

3.5 E-4

549

(4)

32.06 h

Cs-129

Ba-130

5.2 E-4

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

549

(0.2)

3.1 h

550

(0.4)

23.6 h

550

(3)

550 550

T a r g e t Nuclide

Ν ' I

Er-161

Er-162

4.2 E-4

Hf-173

Hf-174

7.6 E-5

5.37 d

Pm-148

Sm-149

5 . 1 E-4

(93)

41.3 d

Pm-148m

Sm-149

1.8 E-4

(0.9)

9.59 h

Dy-155

Dy-156

1.3 E-4

551

(16)

54 d

Eu-148

Eu-151

5.0 E-4

551

(0.4)

18.7 m

Eu-159

Gd-160

1.6 E - 3

551

(0.4)

6.7 d

Lu-172

Lu-175

3.9 E-5

551

(5)

23.8 h

W—187

W-186

5.5 E-3

552

(0.06)

18 m

Se-81

Se-82

3.2 E-4

552

(2)

1.65· h

Ru-95

Ru-96

3.4 E - l 7 . 0 E-4

552

(0.05)

35.3 m

Sn-111

Sn-112

552

(0.01)

69.6 m

Te-129

Te-130

1.9 E - 3

553

(0.6)

39 h

Ge-69

Ge-70, S e - 7 4

7.2 E - 3

553

(16)

86.2 d

Rb-83

Rb-85, Sr-84

1.1 E-3

553

(100)

38 m

In-117

Sn-118

1.1 E - l

As-75, Se-77

2.6 E - 3

554

(2)

26.4 h

As-7 6

554

(70)

35.34 h

Br-82

Br-81, Rb-87

3.5 E - 3

554

(61)

6.3 h

Hb-82m

Sr-84

3.7 E - 3

554

(16)

2.13 h

Ba-129m

Ba-130

3.4 E - 3

556

(98)

1.02 m

Rb-86m

Rb-87, Sr-87

1 . 1 E+l

556

(60)

9.5 h

Sr-91

Zr-96

w

556

(96)

49.7 m

Y-91m

Zr-92

5.0 E - l

556

(2)

42 s

Rh-104

R h - 1 0 3 ,, P d - 1 0 5

2.6

Rh-103, , P d - 1 0 5

1.8 E-2

556

(0.2)

4.4 m

Rh-104m

556

(92)

69.2 h

Ag-104

Cd-106

8 . 5 E-4

556

(60)

33.5 m

Ag-104m

Cd-106

7 . 9 E-3

556

(1)

1.73 h

Nd-149

Nd-150

2 . 6 E-2

557

(2)

206 d

Rh-102

Rh-103, Pd-104

9.1 E-4

557

(0.8)

39.35 d

Ru-103

Ru-104

1.4 E - 3

557

(0.1)

33.6 d

Te-129m

Te-130

7.0 E-5

557

(0.2)

93.1 d

Tm-168

Tm-169

3 . 5 E-4

557

(1)

30 h

Os-193

Os-192

1.0 E - 4

11.3 h

Ge-77

Se-82

4.1 E-5

Pd-109

Pd-110

8.1 E-3

558

(17)

558

( 0 . 0 0 2 ) 13.46 h

558

(3)

49.5 d

In-114m

In-115, Sn-115

7 . 1 E-3

558

(0.06)

93.1 d

Eu-149

Eu-151

8 . 4 E-6

253

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

558

(0.3)

1.37 a

Lu-173

Lu-175,, Hf-174

2.0 E-5

558

(30)

12.1 d

Ir-190

Ir-191

2.2 E - l

559

(44)

26.4 h

As-76

As-75, Se-77

5.7 E-2 1

560

(?)

9.59 h

Dy-155

Dy-156

560

(0.007) 69.6 m

Te-129

Te-130

1.3 E-3

560

(0.02)

18.56 h

Gd-159

Gd-160

8.8 E-4

560

(2)

198.5 m

Tb-163

Dy-164

7.2 E-3

560

(9)

40 h

Hg-195m

Hg-196

2.1 E-4

562

(70)

171 d

Ir-194m

Ir-193, Pt-195

3.8 E-3

564

(0.2)

35.3 m

Sn-111

Sn-112

2.8 E-3

564

(70)

2.7 d

Sb-122

Sb-123, Te-123

1.8

566

(0.15)

18 m

Se-81

Se-82

8.1 E-4

566

(3)

8.47 h

Pd-101

Pd-102

2.5

566

(7)

2.13 h

Ba-129m

Ba-130

1.4 E-3

566

(0.1)

2.35 h

Dy-165

Dy-164

9.4 E-4

567

(0.3)

6.47 d

Cs-132

Cs-133

7.2 E-3

568

(1)

22 m

Rh-107

Pd-108

5.5 E-3

569

(1)

56 h

Br-77

Br-79

2.2 E-3

569

(56)

23.4 h

Nb-96

Mo-9 7

4.3 E-2

569

(28)

12.1 d

Ir-190

Ir-191

2.0 E - l

569

(4)

11 h

Pt-189

Pt-190

3.9 E-3

570

(0.01)

270 d

Co-5 7

Ni-58, Co-59

6.1 E-6

570

(0.8)

2.9 d

Ru-97

Ru .98

3.0 E-3

570

(98)

38 a

Bi-207

Bi-209

2.7 E-4

571

(0.9)

39 m

Se-73ra

Se-74

2.9 E-2

571

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E-5

572

(11)

17 h

Ce-135

Ce-136

4.1 E-3

572

(0.2)

26.4 h

As-76

As-75, Se-77

2.6 E-4

572

(0.04)

120 d

Se-75

Se-76

5.2 E-6

573

(80)

16.8 d

Te-121

Te-122

1.7 E-2

5 73

(2)

15.15 h

Eu-157

Gd-158

2.4 E-4

574

(13)

39 h

Ge-69

Ge-70, Se-74

1.5 E - l

574

(?)

40.27 h

La-140

La-139

9

574

(84)

31 a

Hf-178n

Hf-179

W

575

(0.08)

2.35 h

Dy-165

Dy-164

7.6 E-4

575

(2)

3.8 h

lr-195m

Pt-196

3.0 E-4

576

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E-3

254 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I 5.3 E-5

576

(0.1)

2.8 d

Pt-191

Pt-192

577

(5)

17 h

Ce-135

Ce-136

1.9 E - 3

577

(0.3)

6.7 d

Lu-172

Lu-175

2 . 9 E-5 2.7 E-2

578

(0.03)

68.3 m

Ga-68

Ga-69, Ge-70

578

(3)

39 m

Se-73m

Se-74

1.0 E - l

579

(3)

56 h

Br-77

Br-79

6.6 E - 3

579

(0.15)

1.73 h

Nd-149

Nd-150

3.9 E-3

579

(80)

18.7 h

Au-200m

Hg-201

4.2 E - 6

581

(59)

5.9 m

Rh-108m

Pd-110

w

581

(0.06)

18.56 h

Gd-159

Gd-160

2.6 E - 3

582

(0.49)

6.24 d

Bi-206

Bi-209

1.4 E-5

582

(35)

60 d

Tc-95m

Ru-96

5.6 E-4

584

(0.18)

5.37 h

Ag-113

Cd-114

9 . 4 E-5

584

(0.3)

3.85 d

Sb-127

Te-128

4 . 5 E-5

584

(52)

36 a

Eu-150

Eu-151

7.3 E-5

584

(7)

19.5 m

Tb-163

Dy-164

2.5 E-2

584

(0.08)

2.8 d

Pt-191

Pt-192

4 . 2 E-5

585

(0.4)

6.7 d

Lu-172

Lu-175

3.9 E-5

585

(2)

9.5 h

Hg-195

Hg-196

1.5 E-3

585

(13)

59.6 s

Na-2 5

Mg-26

4.7 E - l

585

(1)

56 h

Br-77

Br-79

2.2 E - 3

586

(0.4)

8.3 d

Ag-106m

Ag-107

1.7 E-4

586

(85)

17.5 s

K-47

Ca-48

3.6 E - 2

586

(0.2)

10 h

Os-183m

Os-184

2.0 E-5

587

(0.3)

9.59 h

Dy-155

Dy-156

4.5 E-5

588

(0.2)

39 h

Ge-69

Ge-70, S e - 7 4

2.4 E - 3

588

(87)

4.16 m

Zr-89m

Zr-90

1.8 E+2

588

(6)

20 h

Rh-100

Pd-102

1.6 E-3

588

(0.1)

2.8 d

Pt-191

Pt-192

5.3 E - 5

589

(0.3)

39 m

Se-73m

Se-74

9 . 6 E-3

589

(1)

3.3 h

Cu-61

Cu-63

1.2 E - 2

589

(0.6)

32.06 h

Cs-129

Ba-130

7.8 E-5

589

(0.4)

18.7 m

Eu-159

Gd-160

1.6 E-3

589

(4)

74 d

Ir-192

Ir-193

5.2 E-3

589

(0.1)

19.4 h

Ir-194

I r - 1 9 3 , Pt-195

9 . 3 E-5

590

(12)

8.47 h

Pd-101

Pd-102

1.0 E+l

591

(1)

23.4 h

Nb-96

Mo-97

7.9 E-4

255 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

591

(17)

14.6 m

Mo-101

Mo-100

9.4 E-3

591

(5)

15.8 s

Tc-100

Ru-101

2.1 E - l

591

(1)

1.65 h

Ru-95

Ru-96

1.7 E - l

591

(1)

20 h

Rh-100

Pd-102

1.7 E-2

592

(5)

8.5 a

Eu-154

Eu-153, Gd-155

9.5 E-6

592

(1)

94 d

Os-185

Os-186

3.6 E-5

593

(3)

3.1 h

Er-161

Er-162

6.3 E-3

594

(13)

22.2 h

K-43

Ca-44

5.2 E-3

594

(3)

7.7 h

Tm-166

Tm-169

1.1 E-4

595

(0.2)

10.98 d

Nd-147

Nd-148

1.1 E-4

595

(0.6)

6.7 d

Lu-172

Lu-175

5.8 E - 5

596

(99)

8.3 m

Ga-74

Ge-76

596

(60)

17.77 d

As-74

As-75, Se-76,

596

(0.3)

18.7 m

Eu-159

Gd-160

597

(24)

9.13 h

Zn-62

Zn-64

1.9 E-2

597

(16)

2.13 h

Ba-129m

Ba-130

3.4 E - 3

598

(?)

1.73 h

Nd-149

Nd-150

·>

598

(0.08)

8.1 h

Dy-157

Dy-158

2.9 E-5

599

(12)

41.3 d

Pm-148m

Sm-149

2.4 E-5 1.9 E-5

4 . 6 E-3 Br-79

4.0 E - l 1.2 E-3

599

(2)

15.2 d

Eu-156

Gd-157

6 00

(2)

9.5 h

Hg-195

Hg-196

1.6 E-3

6 01

(5)

14.1 h

Ga-72

Ge-73, Ga-71

6.5 E - 3

601

(2)

8.3 d

Ag-106m

Ag-107

8.4 E-4

601

(18)

2.77 a

Sb-125

Te-126

1.5 E-5

601

(62)

171 d

Ir-194m

Ir-193, Os-195

3.3 E - 3

602

(0.9)

18.7 m

Eu-159

Gd-160

3.7 E - 3

603

(0.01)

13.46 h

Pd-109

Pd-110

4 . 1 E-2

603

(98)

60.3 d

Sb-124

T e - 1 2 5 , Sb-123

3.5 E-4

603

(20)

1.6 m

Sb-124m

Te-125

w

604

(4)

3.85 d

Sb-127

Te-128

6.0 E - 4

6 04

(8)

74 d

Ir-192

Ir-193

1 . 1 E-2

6 04

(0.3)

20 h

Tc-95

Ru-96

2.4 E-3

605

(0.4)

20 h

Rh-100

Pd-102

1.0 E - 4

605

(98)

2.05 a

Cs-134

Cs-133, Ba-135

7 . 2 E-4

605

(5)

6.8 m

La-134

Ce-136

?

605

(39)

12.1 d

Ir-190

Ir-191

2.7 E - l

606

(8)

34.9 h

Kr-79

Sr-84

w

T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

606

(2)

14.4 m

In-112

In-113

1.0 E - l

606

(22)

17 h

Ce-135

Ce-136

8.1 E-3

607

(3)

3.12 h

Ag-112

Cd-113

4 . 8 E-4

607

(4)

55 m

Cd-105

Cd-106

2.2 E - 3

607

(0.6)

6.7 d

Lu-172

Lu-175

5.8 E-5

(16)

8.3 m

Ga-74

Ge-76

7.5 E-4

608 608

(0.6)

17.77 d

As-74

As-75, Se-76,

608

(4)

19.5 m

Tb-163

Dy-164

1.4 E-2

608

(5)

11 h

Pt-189

Pt-190

4 . 9 E-3

610

(5)

39.35 d

Ru-103

Ru-104

8 . 5 E-3

611

(6)

41.3 d

Pm-148m

Sm-149

1.2 E-5

611

(19)

54 d

Eu-148

Eu-151

8.3 E-5

612

(0.1)

8.47 h

Pd-101

Pd-102

8 . 4 E-2

(5)

74 d

lr-192

Ir-193

6.5 E - 3

612

Br-79

4.1 E-3

613

(1)

18.4 m

Eu-159

Gd-160

4.1 E-3

614

(54)

1.5 h

As-78

Se-80

1.2 E - 2 7.3 E+3

614

(14)

6.46 m

Br-78

Br-79

616

(20)

2.2 h

Rh-106m

Pd-108

1.3 E - l

616

(22)

8.3 d

Ag-106m

Ag-107

9 . 2 E-3

616

(99)

9.9 m

0s-190m

Os-192

1.8 E-2

616

(1)

60 d

Tc-95m

Ru-96

1.6 E-5

Ca-44

3 . 5 E-2

617

(87)

22.2 h

K-43

617

(7)

17.6 m

Br-80

B r - 8 1 , Rb-85

4 . 9 E+3

617

(0.2)

24 m

Ag-106

Ag-107,, Cd-108

2.2

617

(42)

3.12 h

Ag-112

Cd-113

6.8 E-3

617

(94)

3.1 h

Ir-190m

Ir-191

2.6

617

(6)

14.4 m

In-112

In-113

3.1 E - l 5.2 E-2

618

( 0 . 0 0 4 ) 120 d

Se-75

Se-76

618

(0.06)

83 m

Ge-75

Ge-76, S e - 8 0

1.1 E-2

618

(1)

41.2 d

Ag-105

Ag-107,, Cd-106

2.6 E-4

618

(0.01)

18.56 h

Gd-159

Gd-160

4 . 4 E-4

618

(6)

21.8 h

VV-187

W-186

6.6 E-3

619

(0.3)

2.41 m

Ag-108

Ag-109,, Cd-110

1.4

619

(44)

35.34 h

Br-82

B r - 8 1 , Rb-87

2.1 E-3

619

(37)

6.3 h

Rb-82m

Sr-84

2.3 E-3

Pd-102

3 . 4 E-2

Pd-109

w

619

(0.04)

8.47 h

Pd-101

619

(14)

16.8 s

Rh-108

T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

619

(4)

15.15 h

Eu-157

Gd-158

4 . 8 E-4

620

(57)

3.9 h

Zn-71m

Ge-76

7 . 4 E-4

620

(0.03)

12.6 h

Eu-150m

Eu-151

1.8 E-3

620

(6)

6.24 d

Bi-206

Bi-209

1 . 8 E-4

621

(0.09)

2.35 h

Dy-165

Dy-164

8 . 3 E-4

621

(2)

39.5 h

Au-194

Au-197

1.5 E - 3

622

(0.4)

17 h

Ce-135

Ce-136

1.5 E-4

622

(10)

30 s

Rh-106

Pd-108

1.3 E-3

622

(0.9)

7.6 m

Tb-162

Dy-163

3.1 E-3

622

(0.7)

66.9 m

Pb-204m

Pb-206

2.7 E-4

623

(0.3)

24 m

Ag-106

A g - 1 0 7 , Cd-108

3.3

624

(0.09)

69.6 m

Te-129

Te-130

1.7 E-2

624

(37)

36 m

Er-159

Er-162

w

624

(1)

2.8 d

Pt-191

Pt-192

5.3 E - 4

626

(0.09)

3.1 h

Er-161

Er-162

1.9 E-4

626

(0.3)

6.7 d

Lu-172

Lu-175

2.9 E-5

6 26

(1)

23.8 h

W-187

VV-186

1.1 E-3

627

(0.4)

14 m

Tc-101

R u - 1 0 2 , Mo-100

6 . 4 E-4

627

(18)

1.65 h

Ru-95

Ru-96

3.1

627

(1)

11 h

Pt-189

Pt-190

1.0 E - 3

628

(5)

206 d

Rh-102

Rh-103, Pd-104

2.4 E - 3

629

(3)

4.6 m

Ho-169

Er-170

4 . 3 E-2

630

(25)

14.1 h

Ga-72

Ge-73, Ga-71

3.2 E-2

630

(10)

26 h

As-72

Se-74

1.0 E - 4

Cs-132

630

(1)

6.47 d

Cs-133

2.2 E-2

630

(0.2)

1.73 h

Nd-149

Nd-150

5.2 E - 3

630

(89)

41.3 d

Pm-148m

Sm-149

1.7 E - 4

630

(71)

54 d

Eu-148

Eu-151

3 . 3 E-4

630

(1)

19.5 m

Tb-163

Dy-164

3.6 E - 3

630

(29)

4.3 m

Tc-102m

Ru-104

w

631

(56)

2.9 a

Rh-102

R h - 1 0 3 , Pd-104

4 . 7 E-4

631

(0.3)

6.7 d

Lu-172

Lu-175

2.9 E-5

631

(4)

12.1 d

Ir-190

Ir-191

2 . 8 E-2

632

(8)

11.3 h

Ge-77

Se-82

1.9 E-5

632

(8)

93.1 d

Tm-168

Tm-169

1.4 E-2

632

(4)

6.24 d

Bi-206

Bi-209

1.2 E - 4

633

(2)

2.41 m

Ag-108

A g - 1 0 9 , Cd-110

9.8

258 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

633

(0.6)

2.35 h

Dy-165

Dy-164

5.7 E-3

633

(1)

16.98 h

Re-188

Re-187, Os-189

5.8 E-3

633

(23)

41.5 h

Ir-188

I r - 1 9 1 , Pt-190

1.8 E-4

635

(15)

17.77 d

As-74

As-75, Se-76.

635

(0.5)

55 m

Cd-105

Cd-106

2.8 E-4

636

(0.01)

13.46 h

Pd-109

Pd-110

6.0 E-2

636

(12)

2.77 a

Sb-125

Te-126

9.4 E-6

636

(0.9)

1.37 a

Lu-173

L u - 1 7 5 , Hf-174

5.9 E-5

637

(3)

4.4 m

In-118m

Sn-119

1.4 E-4

637

(0.2)

206 d

Kh-102

Rh-103, Pd-104

9 . 3 E-5

638

(0.4)

3.58 d

Sb-127

Te-128

6 . 1 E-5

640

(0.2)

17.6 m

Br-80

B r - 8 1 , Rb-85

1.4 E+2

641

(1)

9.59 h

Dy-155

Dy-156

1 . 5 E-4

642

(2)

38 d

Re-184

Re-185

4 . 0 E-3

644

(84)

16 h

Te-119

Te-120

4 . 3 E-3

644

(0.2)

6.7 d

Lu-172

Lu-175

1.9 E-5

Br-79

1.0 E - l

645

(12)

41.2 d

Ag-105

A g - 1 0 7 , Cd-106

3 . 1 E-3

645

(1)

19.4 h

Ir-194

Ir-193, Pt-195

9 . 5 E-4

645

(2)

39.5 h

Au-194

Au-197

1.5 E-3

646

(1)

8.3 d

Ag-106m

Ag-107

4.3 E-4

646

(7)

60.3 d

Sb-124

T e - 1 2 5 , Sb-123

2.5 E - 5

646

(20)

1.6 m

Sb-124m

Te-125

w

646

(7)

15.2 d

Eu-156

Gd-157

6.6 E-5

646

(0.4)

18.7 m

Eu-159

Gd-160

1.6 E-3 ·>

646

(16)

(5 h)

Ho-160

Er-162

646

(1)

93.1 d

Tm-168

Tm-169

1.7 E-3

646

(82)

94 d

Os-185

Os-186

3 . 0 E-3

647

(0.02)

13.46 h

Pd-109

Pd-110

8 . 0 E-2

648

(2)

55 m

Cd-105

Cd-106

1 . 1 E-3

649

(0.7)

3.1 h

Er-161

Er-162

1.4 E-3

649

(28)

36 m

Er-159

Er-162

w

650

(0.01)

18 m

Se-81

Se-82

5 . 5 E-5

652

(0.4)

3.85 d

Sb-127

Te-128

6.0 E-5

653

(0.01)

33 h

Sr-83

Sr-84

2.8 E-6

653

(48)

65 s

Mo-91m

Mo-9 2

6.7

653

(1)

1.65 h

Ru-95

Ru-96

1.7 E - l

654

(0.3)

9.59 h

Dy-155

Dy-156

4 . 5 E-5

259 T a b . 5-5, continued Ε, keV (14)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

655

(0.7)

20 h

Rh-100

Pd-102

1.8 E-4

655

(8)

1.73 h

Nd-149

Nd-150

2.1 E - l

656

(0.4)

39 m

Se-73m

Se-74

1.3 E-2

656

(10)

3.3 h

Cu-61

Cu-63

1.3 E - l

656

(4.48)

2.13 h

Ba-129m

Ba-130

9.4 E-4

656

(1)

12.1 d

Ir-190

Ir-191

7 . 1 E-3

657

(6)

26.4 h

As-76

As-75, Se-77

7.6 E-3

657

(2)

6.24 d

Bi-206

Bi-209

5.8 E-5

6 58

(5)

24.6 s

Ag-110

A g - 1 0 9 , Cd-111

7.0 E - l

658

(94)

250.4 d

Ag-110m

A g - 1 0 9 , Cd-111

3.9 E-5

658

(98)

69.1 m

In-110

Sn-112

9 . 8 E-2

658

(99)

4.9 h

In-110m

Sn-112

1 . 1 E-2

658

(33)

3.62 h

Pb-202m

Pb-204

9.0 E-5

659

(0.4)

33 h

Sr-83

Sr-84

1 . 1 E-4

659

(98)

74 m

Nb-97

Mo-9 8

1.9

659

(0.01)

109 d

Te-127m

Te-128

1.4 E - 5

660

(1)

18.7 m

Eu-159

Gd-160

4 . 1 E-3

661

(0.5)

48.4 m

Au-200

Hg-201

1.6 E-4

662

(90)

2.55 m

Ba-137m

Ba-138, La-138

6.2 E + l

662

(0.08)

56 h

Br-77

Br-79

1.8 E-4

664

(3)

17 h

Ce-135

Ce-136

1.1 E-3

664

(2)

9.59 h

Dy-155

Dy-156

3.0 E-4

665

(3)

18.7 m

Eu-159

Gd-160

1.3 E-2

665

(0.2)

26.4 h

As-76

As-75, Se-77

2.6 E-4

666

(42)

15.2 s

As-80

Se-82

w

666

(1)

17.6 m

Br-80

B r - 8 1 , Rb-85

6.9 E+2

666

(100)

12.4 d

Sb-126

Te-128

8 . 5 E-6

666

(34)

13 d

1-126

1-127

3.8 E - l

667

(0.3)

35 a

Eu-150

Eu-151

w

668

(0.5)

3.85 d

Sb-127

Te-128

7 . 5 E-5

668

(100)

6.47 d

Cs-132

Cs-133

2.4

668

(0.2)

3.1 h

Ho-167

Er-168

669

(?)

60.2 d

Sb-124

T e - 1 2 5 , Sb-123

2.4 E-4 7

670

(9)

38.4 m

Zn-63

Zn-64

3.9

670

(2)

22 m

Eh-107

Pd-108

1.1 E-2

672

(0.02)

33.6 d

Te-129m

Te-130

1.4 E-5

672

(0.1)

16.93 h

Re-188

Re-187, Os-189

5.9 E-4

T a b . 5-5, continued Ε, keV (1%)

Τ

Nuclide

T a r g e t Nuclide

673

(1)

5.37 h

Ag-113

Cd-114

5.2 E - 4

673

(9)

7.7 h

Tm-166

Tm-169

3.2 E - 4

674

(0.08)

33 h

Sr-83

Sr-84

2.2 E-5

674

(0.1)

93.1 d

Tm-168

Tm-169

1.7 E-4

676

(0.4)

5.98 h

Pr-145

Nd-146

4 . 4 E-4

676

(0.5)

36 a

Eu-150

Eu-151

?

676

Ν ' I

(4)

4.6 m

Ho-169

Er-170

5.6 E-2

676

(1)

2.695 d

Au-198

A u - 1 9 7 , Hg-199

8 . 8 E-4

677

(2)

18.7 m

Eu-159

Gd-160

8.2 E-3

678

(11)

250.4 d

Ag-110m

Ag-109, Cd-111

4 . 6 E-6 2.3 E-3

679

(15)

2.13 h

Ba-129m

Ba-130

679

(0.2)

9.58 h

Dy-155

Dy-156

3.0 E-5

680

(2)

8.3 d

Ag-106m

Ag-107

8 . 4 E-4

681

(0.6)

206 d

Rh-102

Rh-103, Pd-104

2 . 8 E-4

681

(0.7)

5.37 h

Ag-113

Cd-114

3.6 E - 4

681

(0.7)

52.1 h

Pb-203

Pb-204

9 . 6 E-4

682

(0.5)

3.85 d

Sb-127

Te-128

7 . 5 E-5

682

(2)

18.7 m

Eu-159

Gd-160

8.2 E-3

682

(1.2)

72.1 d

Tb-160

T b - 1 5 9 , Dy-161

5.2 E - 5

682

(0.7)

6.7 d

Lu-172

Lu-175

6 . 8 E-5

683

(55)

4.4 m

In-118m

Sn-119

2.6 E-3

683

(0.1)

16 h

Te-119

Te-120

5 . 1 E-6

684

(0.4)

17 h

Ce-135

Ce-136

1 . 5 E-4

684

(6)

4.32 h

Sb-129

Te-130

2.0 E-3

685

(100)

6.9 h

Mo-93m

Mo-94

3.2 E - l

685

(13)

3.8 h

Ir-195m

Pt-196

2 . 0 E-2

3.85 d

Sb-127

Te-128

5.4 E - 3 3 . 8 E-4

686

(36)

686

(0.7)

10.98 d

Nd-147

Nd-148

686

(26)

23.8 h

W-187

W-186

2 . 8 E-2

686

(2)

1.5 h

As-78

Se-80

4.3 E-4

687

(0.8)

20 h

Rh-100

Pd-102

2.0 E-4

687

(1)

15.15 h

Eu-157

Gd-158

1.2 E - 4

687

(0.008) 2.8 d

Pt-191

Pt-192

4.2 E-6

688

(59)

171 d

Ir-194m

Ir-193, Pt-195

3.2 E - 3

689

(4)

2.13 h

Ba-129m

Ba-130

8 . 4 E-4

689

(0.9)

12.4 a

Eu-152

Eu-153

7 . 6 E-6

690

(0.2)

12.1 d

Ir-190

Ir-191

1.4 E - 3

261

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

Target Nuclide

1.4 E-3

Ν ' I

691

(0.3)

3.1 h

Er-161

Er-162

691

(7)

7.7 h

Tm-166

Tm-169

6.3 E-4

692

(0.2)

270 d

Co-57

Ni-58, Co-59

2.5 E-4

693

(4)

2.7 d

Sb-122

Sb-123, Te-123

1.2 E-4

694

(4)

3.12 h

Ag-112

Cd-113

1.0 E - l

694

(0.5)

18.7 m

Eu-159

Gd-160

6.4 E-4

694

(0.01)

2.35 h

Dy-165

Dy-164

2.1 E-3

695

(18)

1.5 h

As-78

Se-80

9.5 E-5

695

(0.1)

6.46 m

Br-78

Br-79

3.9 E-3

695

(100)

12.4 d

Sb-126

Te-128

5.2 E+l

695

(0.2)

9.59 h

Dy-155

Dy-156

8.3 E-6

696

(3)

33.6 d

Te-129m

Te-130

3.0 E-5

696

(1)

17.3 m

Pr-144

Nd-145

2.1 E-3

697

(44)

2.9 a

Rh-102m

Rh-103,, Pd-104

6.8 E-2

697

(2)

7.6 m

Tb-162

Dy-163

3.7 E-4

697

(6)

6.7 d

Lu-172

Lu-175

6.8 E-3

697

(?)

6.24 d

Bi-206

Bi-209

5.8 E-4

698

(29)

35.34 h

Br-82

Br-81, Rb-87

·>

698

(0.02)

6.1 m

Br-82m

Br-81

1.5 E-3

699

(4)

3.85 d

Sb-127

Te-128

1.1 E+l

7 00

(10)

16 h

Te-119

Te-120

6.0 E-4

701

(2.4)

2.13 h

Ba-129m

Ba-130

5.1 E-4

701

(99)

2.5 m

Fe-53m

Fe-54, Ni-58

5.1 E-4

702

(0.003) 13.46 h

Pd-109

Pd-110

1.6 E-3

7 02

(0.02)

33.6 d

Te-129m

Te-130

1.2 E-2

7 02

(0.02)

8.74 h

Pd-101

Pd-102

1.4 E-5

703

(0.3)

39 m

Se-73m

Se-74

1.7 E-2

7 03

(100)

4.9 h

Tc-94

Ru-96

9.6 E-3

703

(5)

2.2 h

Rh-106m

Pd-108

5.0 E-2

703

(4)

8.3 d

Ag-106m

Ag-107

3.3 E-2

703

(0.3)

55 m

Cd-105

Cd-106

1.7 E-3

7 03

(0.3)

15.9 m

Sb-120

Sb-121

1.7 E-4

7 04

(0.2)

17.6 m

Br-80

Br-81, Rb-85

2.3

705

(10)

7.7 h

Tm-166

Tm-169

1.4 E+2

707

(0.002) 13.46 h

Pd-109

Pd-110

3.5 E-4

707

(16)

250.4 d

Ag-110m

Ag-109,, Cd-111

8.0 E-3

7 08

(26)

5.5 h

Nd-139m

Nd-142

6.6 E-6

262 T a b . 5-5, continued E.keV ' (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

7 02

(0.02)

33.6 d

702

(0.02)

8.74 h

Te-129m

Te-130

1.4 E - 5

Pd-101

Pd-102

7 03

(0.3)

1.7 E-2

39 m

Se-73m

Se-74

9.6 E-3

703 703

(100)

4.9 h

Tc-94

Ru-96

5.0 E-2

(5)

2.2 h

Rh-106m

Pd-108

3.3 E-2

703

(4)

8.3 d

Ag-106m

Ag-107

1.7 E-3

7 03

(0.3)

55 m

Cd-105

Cd-106

1.7 E-4

703

(0.3)

15.9 m

Sb-120

Sb-121

2.3

704

(0.2)

17.6 m

Br-80

B r - 8 1 , Rb-85

1.4 E+2

7 05

(10)

7.7 h

Tm-166

Tm-169

3 . 5 E-4

707

( 0 . 0 0 2 ) 13.46 h

Pd-109

Pd-110

8 . 0 E-3

707

(16)

250.4 d

Ag-110m

Ag-109, , Cd-111

6.6 E-6

708

(26)

5.5 h

Nd-139m

Nd-142

6 . 0 E-5

709

(20)

57.7 m

Cd-104

Cd-106

w

7 09

(0.9)

15.2 d

Eu-156

Gd-157

8 . 1 E-4

709

(0.7)

6.7 d

Lu-172

Lu-175

6 . 8 E-5

710

(0.1)

55 m

Cd-105

Cd-106

5.7 E - 5

710

(0.08)

22 m

Rh-107

Pd-108

4.4 E-4

712

(3)

2.13 h

Ba-129m

Ba-130

712

(1)

36 a

Eu-150

Eu-151

6.3 E-4 ?

714

(8)

11.3 h

Ge-77

Se-82

1.9 E-5 1.7 E-5

714

(0.06)

33 h

Sr-83

Sr-84

715

(0.2)

8.2 m

As-79

Se-80

2.6 E-3

715

(2)

53 d

Eu-148

Eu-151

8.6 E-6

715

(0.5)

2.35 h

Dy-165

Dy-164

4.8 E-3

716

(0.06)

14 m

Tc-101

Ru-102, Mo-100

9.4 E-5

716

(29)

8.3 d

Ag-106m

Ag-107

1.2 E-2 2.0 E - l

717

(30)

2.2 h

Rh-106m

Pd-108

717

(4)

94 d

Os-185

Os-186

1.5 E-4

718

(0.2)

3.12 h

Ag-112

Cd-113

3.2 E - 5

719

(0.3)

23.6 h

Hf-173

Hf-174

5.7 E-5

719

(0.4)

17 h

Ce-135

Ce-136

1.5 E-4

719

(0.1)

74 m

Nb-97

Mo-98

1.9 E-3

7 20

(0.2)

3.08 h

Ti-45

Ti-46

5.9 E-3

720

(7)

23.4 h

Nb-96

Mo-97

5.4 E-3

720

(58)

12.5 d

Sb-126

Te-128

5.0 E-6

720

(0.2)

18.7 m

Eu-159

Gd-160

8 . 3 E-4

263 T a b . 5-5, continued E , k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν · I

Tm-168

Tm-169

1.8 E-2

720

(11)

93.1 d

721

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E-5

721

(6)

11 h

Pt-189

Pt-190

5.9 E-3

722

(2)

3.85 d

Sb-127

Te-128

3 . 0 E-4

7 23

(75)

51 m

Nb-98

Mo-100

4 . 1 E-3

723

(11)

60.3 d

Sb-124

Te-125, Sb-123

4.0 E-5

723

(19.1)

8.5 a

Eu-154

Eu-153, Gd-155

3.6 E-5

723

(6)

15.2 d

Eu-156

Gd-157

5.6 E-5

723

(0.5)

6.7 d

Lu-172

Lu-175

4 . 8 E-5

7 24

(0.06)

8.2 m

As-79

Se-80

7 . 8 E-4

724

(44)

64 d

Zr-95

Zr-96

2 . 3 E-2

724

(48)

4.44 h

Ru-105

Ru-104

9 . 6 E-3

724

(2)

8.47 h

Pd-101

Pd-102

1.6

7 25

(0.2)

39 m

Se-73m

Se-74

6 . 4 E-3

725

(3)

49.5 d

In-114m

In-115, S n - 1 1 5

6 . 6 E-3

726

(32)

41.3 d

Pm-148m

Sm-149

6.4 E-5

726

(12)

54 d

Eu-148

Eu-151

5.1 E-5

726

(0.7)

18.7 m

Eu-159

Gd-160

2.9 E-3

7 26

(4)

12.1 d

Ir-190

Ir-191

2.4 E-2

727

(0.7)

3.1 h

Er-161

Er-162

1.5 E-3

7 28

(30)

5 h

Ho-160m

Er-162

?

730

(0.7)

33.6 d

Te-129m

Te-130

4 . 9 E-4

731

(4)

93.1 d

Tm-168

Tm-169

6.8 E-3

732

(0.06)

33 h

Sr-83

Sr-84

1.7 E - 5

733

(0.2)

18.7 m

Eu-159

Gd-160

8 . 2 E-4

7 34

(0.2)

77.3 d

Co-5 6

Ni-58

2.6 E-6

734

(0.1)

206 d

Rh-102

Rh-103, Pd-104

4 . 7 E-5

7 35

(0.4)

1.65 h

Ru-95

Ru-96

6.8 E-2

7 35

(0.3)

20 h

Rh-100

Pd-102

7.8 E-5

735

(0.4)

20 h

Pt-189

Pt-190

3.9 E-4

33 h

737

(0.2)

Sr-83

Sr-84

5.6 E-5

7 37

( 0 . 0 0 2 ) 13.46 h

Pd-109

Pd-110

8.2 E-3

737

(0.2)

3.1 h

Er-161

Er-162

4.2 E - 4

7 37

(0.3)

14 h

Os-183

Os-184

8.2 E-6

737

(9)

36 a

Eu-150

Eu-151

1.3 E - 5

738

(35)

5.5 h

Nd-139m

Nd-142

8.0 E-5

7 39

(6)

4.8 h

Ga-73

Ge-74

5 . 1 E-2

264

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

739

(13)

66 h

Mo-9 9

Mo-100

4.0 E-2

740

(0.2)

26.4 h

As-76

As-75, Se-77

2.6 E-4

740

(0.5)

206 d

Rh-102

Rhl03, Pd-104

2.4 E-4 6.4 E-5

741

(7)

69.2 h

Ag-104

Cd-106

741

(0.03)

69.6 m

Te-129

Te-130

5.7 E-3

741

(0.03)

33.6 d

Te-129m

Te-130

2.1 E-5

741

(11)

93.1 d

Tm-168

Tm-169

1.9 E-2

742

(39)

265 d

Pm-143

Sm-144

6.6 E-4

743

(98)

53 s

Nb-97m

Mo-98

1.1

743

(0.6)

41.2 d

Ag-105

Ag-107, Cd-106

1.6 E-4

744

(85)

5.7 d

Mn-52

Fe-54

1.4 E-4

744

(1)

18.7 m

Eu-159

Gd-160

4.1 E-3

744

(0.4)

9.59 h

Dy-155

Dy-156

6.0 E-5

745

(0.2)

3.1 h

Ho-167

Er-168

0.4 E-4

745

(0.3)

23.8 h

VV-187

VV-186

3.3 E-4

746

(0.5)

55 m

Cd-105

Cd-106

2.8 E-4

746

(0.1)

3.85 d

Sb-127

Te-128

1.5 E-5

7 48

(0.5)

8.47 h

Pd-101

Pd-102

4.2 E - l

748

(20)

2.2 h

Rh-106m

Pd-108

1.3 E - l 8.8 E-3

748

(21)

8.3 d

Ag-106m

Ag-107

748

(0.3)

93.1 d

Tm-168

Tm-169

5.1 E-4

748

(0.4)

5.98 h

Pr-145

Nd-146

4.4 E-4

749

(2)

1.65 h

Ru-95

Ru-961

3.4 E - l

749

(1)

20 h

Rh-100

Pd-102

2.6 E-4 1.4 E-3

749

(7)

2.13 h

Ba-129m

Ba-130

750

(8)

6 a

Eu-150

Eu-151

1.2 E-5

7 50

(48)

6.1 d

Ni-56

Ni-58

9.8 E-4

752

(4)

40.2 h

La-140

La-139

4.8 E-4

752

(0.4)

15.15 h

Eu-157

Gd-158

4.8 E-5

753

(0.1)

33 h

Sr-83

Sr-84

2.8 E-5

754

(4)

13 d

1-126

1-127

4.4 E-2

754

(93)

56.5 s

Ce-139m

Ce-140

1.3 E+2

754

(0.04)

1.73 h

Nd-149

Nd-150

1.0 E-3

754

(90)

65 s

Sm-143m

Sm-144

1.2

754

(1)

18.7 m

Eu-159

Gd-160

4.1 E-3

755

(0.5)

6.24 d

Bi-206

Bi-209

1.5 E-5

756

(2)

56 h

Br-77

Br-79

4.4 E-3

265

T a b . 5-5, continued Ε, keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

757

(?)

2.246 m

Al-28

Si-29, P-31, Al-27

?

757

(55)

64 d

Zr-95

Zr-96

2.7 E-2

757

(91)

62 s

Nd-141m

Nd-142

5.0

757

(4.1)

8.5 a

Eu-154

Eu-153,, Gd-155

7.8 E-6

7 59

(6)

69.2 h

Ag-104

Cd-106

5.5 E-5

7 59

(0.04)

6.2 d

Au-196

Au-197

1.0 E-3

760

(0.3)

9.9 m

La-136

La-138

6.9 E-4

760

(74)

18.7 h

Au-200m

Hg-201

3.9 E-6

760

(0.1)

9.59 h

Dy-155

Dy-156

1.5 E-5

761

(11)

4.6 m

Ho-169

Er-170

1.6 E - l

761

(0.7)

37.3 m

Sn-111

Sn-112

9.7 E-3

7 62

(0.2)

34.4 h

Ce-137m

Ce-138

9.0 E-6

7 62

(0.2)

39 h

Ge-69

Ge-70, Se-74

2.4 E-3

7 63

(30)

33 h

Sr-83

Sr-84

8.4 E-3

7 63

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E-3

763

(100)

2.3 m

In-119

Sn-120

1.1 E - l

764

(22)

250.4 d

Ag-110m

Ag-109 , Cd-111

9.0 E-6

765

(2)

72.1 d

Tb-160

Tb-159 , Dy-161

8.6 E-5

765

(4)

(5 h)

Ho-160m

Er-162

f

766

(100)

35.15 d

Nb-95

Mo-96, Zr-96

2.6 E-3

7 66

(93)

20 h

Tc-95

Ru-96

7.4 E - l

767

(0.2)

4.54 d

Ca-47

Ca-48

7.4 E-6

7 67

(34)

2.9 a

Rh-102m

Rh-103 , Pd-104

2.8 E-4

767

(66)

69.2 h

Ag-104

Cd-106

6.1 E-4

768

(2)

4.8 h

Ga-73

Ge-74

1.8 E-2

769

(0.3)

16 h

Te-119

Te-120

5.1 E-6

7 69

(0.003) 33.6 d

Te-129m

Te-130

2.1 E-6

7 69

(3)

2.13 h

Ba-129m

Ba-130

6.3 E-4

769

(2)

12.1 d

Ir-190

Ir-191

1.4 E-2

770

(0.5)

39 m

Se-73m

Se-74

1.6 E-2

770

(0.7)

38 d

Re-184

Re-185

1.4 E-3

772

(0.1)

26.4 h

As-76

As-75, Se-77

1.3 E-4

772

(0.08)

6.47 d

Cs-132

Cs-133

1.9 E-3

773

(4)

23.8 h

VV-187

W-186

4.4 E-3

777

(83)

35.34 h

Br-82

Br-81, Rb-87

4.1 E-3

777

(0.2)

6.1 m

Br-82m

Br-81

1.1 E+2

777

(14)

1.3 m

Rb-82

Sr-84

5.3 E-3

266

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

Sr-84

5.1 E-3

777

(83)

6.3 h

Rb-82m

778

(2)

33 h

Sr-83

Sr-84

5.6 E-4

778

(97)

23.4 h

Nb-96

Mo-9 7

7.5 E-2 1.3 E-2

778

(4)

66 h

Mo-99

Mo-100

778

(100)

4.3 d

Tc-96

Ru-98

2.6 E-4

778

(2)

52 m

Tc-96m

Ru-98

2.6 E-6

778

(11)

4.6 m

Ho-169

Er-170

1.6 E - l

779

(13)

12.4 a

Eu-152

Eu-153

1.1 E-4

779

(20)

7.7 h

Tm-166

Tm-169

7.0 E-4

780

(9)

150 a

Tb-158

Tb-159

2.0 E-5

780

(8)

9.5 h

Hg-195

Hg-196

6.2 E-3

781

(0.01)

13.46 h

Pd-109

Pd-110

4.1 E-2

781

(7)

2.13 h

Ba-129m

Ba-130

1.5 E-3

783

(10)

17 h

Ce-135

Ce-136

3.7 E-3

784

(15)

3.85 d

Sb-127

Te-128

2.3 E-3

784

(0.5)

6.24 d

Bi-206

Bi-209

1.5 E-5

786

(9)

60 d

Tc-95m

Ru-96

1.4 E-4

786

(9)

69.2 h

Ag-104

Cd-106

8.2 E-5

786

(0.5)

26 h

As-72

Se-74

5.0 E-6

786

(10)

7.7 h

Tm-166

Tm-169

3.5 E-4

787

(100)

53 m

Cs-135m

Ba-136

7.7 E-4

787

(3)

14.1 d

Ga-72

Ge-73, Ga-71

3.9 E-3

787

(93)

51 m

Nb-98

Mo-100

5.0 E-3

787

(50)

3.62 h

Pb-202m

Pb-204

1.4 E-4

788

(0.3)

77.3 d

Co-5 6

Ni-58

3.9 E-6

788

(0.4)

39 h

Ge-69

Ge-70, Se-74

4.8 E-3

788

(0.3)

16 h

Te-119

Te-120

3.3 E-5

789

(?)

2.58 h

Mn-56

Mn-55, Fe-57

?

789

(2)

1.44 m

Pr-138

Pr-141

w

789

(99)

2.02 h

Pr-138m

Pr-141

w

790

(0.7)

86.2 d

Rb-83

Rb-85, Sr-84

4.5 E-5

790

(0.09)

22 m

Rh-107

Pd-108

5.0 E-4

790

(0.08)

3.85 d

Sb-127

Te-128

1.2 E-5

790

(0.02)

8.47 h

Pd-101

Pd-102

1.7 E-2

792

(38)

38 d

Re-184

Re-185

7.6 E-2

793

(6)

8.3 d

Ag-106m

Ag-107

2.6 E-3

793

(0.01)

2.7 d

Sb-122

Sb-123, Te-123

2.6 E-4

267 T a b . 5-5, continued Τ

Nuclide

T a r g e t Nuclide

Ν ' I

793

(0.8)

11 h

Pt-189

Pt-190

7.8 E-4

796

(5)

2.06 a

Cs-134

Cs-133,

796

(0.6)

7.5 h

Er-171

Er-170

1.4 E-4

797

(0.06)

6.5 h

Cd-107

Cd-108

6 . 0 E-5

799

(0.1)

3.1 h

Er-161

Er-162

799

(0.1)

86.2 d

Rb-83

Rb-85,

8 01

(1)

3.8 h

Ir-195m

Pt-196

1.5 E-4

802

(0.2)

69.6 m

Te-129

Te-130

3.8 E-2

803

(10)

2.13 h

Ba-129m

Ba-130

2.0 E-3

803

(99)

6.24 d

Bi-206

Bi-209

2.9 E-3

804

(12)

8.3 d

Ag-106m

Ag-107

5.0 E-3

804

(0.2)

3.1 h

Er-161

Er-162

4 . 2 E-4

805

(3)

2.2 h

Rh-106m

Pd-108

8 . 5 E-2

805

(0.02)

33 h

Sr-83

Sr-84

5.6 E-6

E.keV (1%)

Ba-135

6.1 E-4

2 . 1 E-4 Sr-84

6.3 E-5

805

(3)

18.7 m

Eu-159

Gd-160

1.3 E-2

806

(0.09)

68.3 m

Ga-68

Ga-69, Ge-70

8 . 1 E-2

8 06

(4)

1.65 h

Ru-95

Ru-96

6.8 E - l

807

(43)

7.6 m

Tb-162

Dy-163

807

(1)

41.2 d

Ag-105

Ag-107,

808

(7)

4.54 d

Ca-47

Ca-48

8 08

(4)

8.3 d

Ag-106m

Ag-107

1.7 E-3

809

(0.3)

3.1 h

Er-161

Er-162

6.3 E-4

1.5 E - l Cd-106

2.6 E-4 2 . 6 E-4

810

(2)

14.1 h

Ga-72

Ge-73,

810

(10)

23.4 h

Nb-96

Mo-97

Ga-71

2.6 E-3 7.6 E-3

810

(0.3)

12.4 a

Eu-152

Eu-153

2 . 5 E-6

810

(16)

6.7 d

Lu-172

Lu-175

1.6 E-3

811

(100)

70.78 d

Co-58

Co-59, Ni-60, Cu-63

1.4 E - l

812

(10)

15.2 d

Eu-156

Gd-157

9.3 E-5

812

(75)

6.1 d

Ni-56

Ni-58

1.6 E-3

812

(0.3)

9.59 h

Dy-155

Dy-156

4 . 5 E-5 6 . 1 E-4

812

(0.3)

3.1 h

Er-161

Er-162

813

(82)

4.3 d

Tc-96

Ru-98

813

( 0 . 0 0 4 ) 17.6 m

Br-80

Br-81,

813

(46)

4.32 h

Sb-129

Te-130

814

(3)

4.4 m

In-118m

Sn-119

1.4 E-4

814

(?)

107 d

Y-88

Y-89, Zr-90

7

816

(0.1)

3.12 h

Ag-112

Cd-113

1.6 E-5

2 . 1 E-4 Rb-85

2.8 1.5 E-2

268

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

816

(23)

40.2 h

La-140

La-139

2.7 E-3

816

(46)

93.1 d

Tm-168

Tm-169

7.8 E-2

816

(1)

6.7 d

Lu-172

Lu-175

1.0 E-4

817

(0.03)

39 h

Ge-69

Ge-70, Se-74

3.6 E-4

817

(0.3)

3.3 h

Cu-61

Cu-63

3.6 E-3

817

(0.4)

3.84 d

Sb-127

Te-128

6.0 E-5

817

(0.09)

33.6 d

Te-129m

Te-130

6.3 E-5

818

(100)

13 d

Cs-136

Ba-137

1.1 E-3

818

(2)

56 h

Br-77

Br-79

4.4 E-3

819

(0.8)

33 h

Sr-83

Sr-84

2.2 E-4

819

(0.6)

1.65 h

Ru-95

Ru-96

1.0 E - l

819

(12)

54 m

In-116ml

In-115, Sn-117

1.1

819

(3)

9.9 m

La-136

La-138

7.0 E-3

820

(4)

2.13 h

Ba-129m

Ba-130

8.4 E-4

821

(0.2)

3.85 d

Sb-127

Te-128

3.1 E-5

821

(5)

60 d

Tc-95m

Ru-96

7.8 E-5

821

(0.02)

8.47 h

Pd-101

Pd-102

1.7 E-2

821

(11)

93.1 d

Tm-168

Tm-169

1.9 E-2

821

(0.3)

9.5 h

Hg-195

Hg-196

2.3 E-4

823

(0.1)

66 h

Mo-99

Mo-100

3.1 E-4

823

(21)

20 h

Rh-100

Pd-102

5.5 E-3

824

(0.01)

56 h

Br-77

Br-79

2.2 E-5

825

(15)

8.3 d

Ag-106m

Ag-107

6.3 E-3

825

(0.4)

34.4 h

Ce-137m

Ce-138

1.8 E-5

826

(0.1)

9.59 h

Dy-155

Dy-156

1.5 E-5

8 27

(61)

3.1 h

Er-161

Er-162

1.3 E - l

1.5 h

As-78

Se-80

1.7 E-3

828

(8)

828

(0.3)

18 m

Se-81

Se-82

1.7 E-3

828

(26)

35.34 h

Br-82

Br-81, Sr-87

1.3 E-3

828

(1)

14.6 h

Nb-90

Mo-92

3.8 E-4

828

(5)

17 h

Ce-135

Ce-136

1.9 E-3

828

(10)

5.5 h

Nd-139

Nd-142

2.3 E-5

829

(0.2)

6.5 h

Cd-107

Cd-108

2.0 E-4

829

(4)

12.1 d

Ir-190

Ir-191

2.9 E-2

830

(0.6)

18.7 m

Eu-159

Gd-160

2.5 E-3

830

(6)

93.1 d

Tm-168

Tm-169

1.0 E-2

269 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

830

(0.4)

16.98 h

Re-188

Re-187, Os-189

2.4 E-3

832

(1)

34.9 h

Kr-79

Sr-84

w

832

(0.2)

12.6 h

Eu-150m

Eu-151

1.2 E-2

833

(0.04)

69.6 m

Te-129

Te-130

7.6 E-3

833

(1)

19.5 m

Tb-163

Dy-164

3.6 E-3

8 34

(6)

3 m

Cu-69

Zn-70

1.9 E-3

834

(96)

14.1 h

Ga-72

Ge-73, Ga-71

1.2 E - l

834

(100)

26 h

As-72

Se-74

1.0 E-3

834

(0.04)

33.6 d

Te-129m

Te-130

2.8 E-5

834

(3)

2.13 h

Ba-129m

Ba-130

6.3 E-4

835

(100)

312.2 d

Mn-54

Mn-55, F e - 5 6 , Co-59

2.0 E-2

Ν ' I

835

(30)

60 d

Tc-95m

Ru-96

4.8 E-4

835

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E - 5

835

(0.1)

34.4 h

Ce-137m

Ce-138

4 . 5 E-6

835

(100)

43 s

V-54

Cr-54

w

837

(0.02)

22 m

Rh-107

Pd-108

1 . 1 E-4

839

(1)

12.1 d

Ir-190

Ir-191

7 . 1 E-3

840

(96)

53 m

Cs-135m

Ba-136

7.4 E-4

840

(0.7)

10 h

Os-183m

Os-184

7.0 E - 5

841

(0.2)

3.3 h

Cu-61

Cu-63

2.4 E-3

8 41

(0.3)

9.59 h

Dy-155

Dy-156

4 . 5 E-5

841

(0.7)

9.5 h

Hg-195

Hg-196

5.9 E-4

841

(0.4)

12.4 a

Eu-152

Eu-153

3.4 E-6

842

(1)

1.65 h

Ru-95

Ru-96

1.7 E - l

842

(13)

9.3 h

Eu-152m2

Eu-153

9 . 8 E-2

843

(0.2)

14 m

Tc-101

Ru-102,, Mo-100

3.2 E-4

844

(0.3)

16 h

Te-119

Te-120

1.5 E-5

844

(72)

9.46 m

Mg-27

Al-27

1.7 E - l

845

(0.1)

17 h

Ce-135

Ce-136

3.8 E-5

845

(0.03)

22 m

Rh-107

Pd-108

1.7 E-4

845

(0.03)

33.6 d

Te-129m

Te-130

2.1 E - 5

847

(99)

2.58 h

Mn-56

Mn-55, Fe-57

3.7 E - l

847

(99)

77.3 d

Co-56

Ni-58

1.3 E-3

848

(4)

8.3 d

Ag-106m

Ag-107

1.7 E-3

848

(3)

5.7 d

Mn-52

Fe-54

5 . 1 E-6

848

(0.2)

33 h

Sr-83

Sr-84

5.5 E - 5

849

(0.2)

9.59 h

Dy-155

Dy-156

3 . 0 E-5

T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

850

(21)

23.4 h

Nb-96

Mo-9 7

1.6 E-2

850

(98)

4.9 h

Tc-94

Ru-96

4.9 E-2

850

(97)

4.3 d

Tc-96

Ru-98

2 . 5 E-4

851

(0.9)

39 m

Se-73m

Se-74

2.9 E-2

851

(1)

3.12 h

Ag-112

Cd-113

1.6 E-4

851

(4)

14 h

Os-183

Os-184

1.0 E - 4

853

(12)

4.6 m

Ho-169

Er-170

1.7 E - l

8 54

(0.2)

33 h

Sr-83

Sr-84

5.5 E-5

854

(0.1)

8.47 h

Pd-101

Pd-102

8 . 4 E-2

857

(17)

12.4 d

Sb-126

Te-128

1.4 E-6

858

(10)

69.2 h

Ag-104

Cd-106

9.2 E-5

8 58

(6)

15.2 m

Tm-175

Yb-176

1.8 E-2

8 59

(0.1)

53.1 h

Pm-149

Sm-150

8.1 E-5

862

(0.2)

3.12 h

Ag-112

Cd-113

3.2 E - 5

863

(7)

69.2 h

Ag-104

Cd-106

8 64

(1)

70.78 d

Co-58

Co-59, Ni-60,

865

(0.6)

7.1 h

Se-73

Se-74

9.1 E-4

865

(1)

3.1 h

Er-161

Er-162

2.1 E-3

865

(0.3)

23.8 h

W-187

VV-186

3 . 3 E-4

866

(5)

4.6 m

Ho-169

Er-170

7 . 0 E-2

867

(?)

36 h

Ni-57

Ni-58

867

(4)

12.4 a

Eu-152

Eu-153

3 . 3 E-5

867

(1)

15.2 d

Eu-156

Gd-157

9 . 6 E-6

8 68

(6)

40.2 h

La-140

La-139

7.2 E-4

8 69

(2)

36 a

Eu-150

Eu-151

2 . 8 E-6

870

(5)

54 d

Eu-148

Eu-151

2 . 1 E-5

870

(0.08)

9.3 h

Eu-152m

Eu-153

6.0 E-4

6 . 4 E-5 Cu-63

1.4 E-3

871

(0.2)

6.26 m

Nb-94m

Mo-95, Nb-93

1.6 E-2

871

(100)

4.9 h

Tc-94

Ru-96

5.0 E-2

871

(94)

53 m

Tc-94m

Ru-96

7.0 E - 3

871

(3)

17 h

Ce-135

Ce-136

1.1 E-3

8 71

(0.2)

18.7 m

Eu-159

Gd-160

8.2 E-4

872

(9)

39 h

Ge-69

Ge-70, S e - 7 4

1.1 E - l

872

(0.2)

72.1 d

Tb-160

Tb-159

Dy-161

8 . 6 E-6

8 73

(0.2)

24 m

Ag-106

Ag-107

Cd-108

2.2

873

(6)

2.13 h

Ba-129m

Ba-130

1.2 E - 3

873

(11)

8.5 a

Eu-154

E u - 1 5 3 , Gd-155

2 . 0 E-5

271

T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν · I

875

(7)

94 d

Os-185

Os-186

2.6 E-4

876

(0.2)

9.76 m

Cu-62

Cu-63, Zn-64

1.6

876

(2)

4.6 m

Ho-169

Er-170

2.8 E-4

878

(0.02)

64.9 d

Sr-85

Sr-86

2 . 0 E-6

879

(2)

8.2 m

As-79

Se-80

2.5 E-2

879

(2)

10 h

Os-183m

Os-184

2.0 E - 4

879

(30)

72.1 d

Tb-160

T b - 1 5 9 , Dy-161

879

(20)

(5 h)

Ho-160m

Er-162

1.3 E - 3 9

879

(0.1)

23.8 h

VV-187

W-186

1.1 E-4

880

(0.8)

13 d

1-126

1-127

8 . 8 E-3

880

(5)

94 d

Os-185

Os-186

1.8 E-4 8 . 4 E-2

881

(0.1)

8.47 h

Pd-101

Pd-102

881

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E - 3

881

(67)

6.24 d

Bi-206

Bi-209

2.0 E - 3

882

(74)

34.5 d

Rb-84

Rb-85, Sr-86

2.0 E - l

882

(13)

7.6 m

Tb-162

Dy-163

4 . 4 E-2

884

(0.3)

5.37 h

Ag-113

Cd-114

1.6 E-4

885

(0.6)

55 m

Cd-105

Cd-106

3 . 3 E-4

885

(73)

250.4 d

Ag-110m

Ag-109 , C d - 1 1 1

3 . 0 E-5

885

(95)

4.9 h

In-110m

Sn-112

887

(0.03)

17.77 d

As-74

As-75, Se-76,

888

(39)

7.6 m

Tb-162

Dy-163

1.4 E-2

1 . 1 E-2 Br-79

2.0 E - 4

889

(1)

1.5 h

As-78

Se-80

2.2 E - 4

889

(100)

84 d

Sc-46

Ti-47, Sc-45

2.1 E-3

889

(0.2)

33 h

Sr-83

Sr-84

5.5 E-5

889

(2)

1.65 h

Ru-95

Ru-96

3.4 E - l

891

(2)

14.6 h

Nb-90

Mo-9 2

7 . 6 E-4

891

(0.5)

9.59 h

Dy-155

Dy-156

892

(21)

51.8 m

Ru-94

Ru-96

7 . 7 E-5 ?

893

(21)

2.13 h

Ba-129m

Ba-130

4.4 E-3

894

(10)

14.1 h

Ga-72

G e - 7 3 , Ga-71

1.3 E-2

894

(0.8)

26 h

As-72

Se-74

8 . 0 E-6

894

(8)

15.2 m

Tm-175

Yb-176

2 . 6 E-2

895

(3)

13 h

Re-182m

Re-185

w

895

(16)

38 d

Re-184

Re-185

3.2 E-2

895

(15)

6.24 d

Bi-206

Bi-209

4.3 E-4

896

(0.7)

3.1 h

Er-161

Er-162

1.4 E - 3

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

898

(0.1)

38 a

Bi-207

Bi-209

2.7 E-7

898

(?)

36 h

Ni-57

Ni-58

898

(14)

17.8 m

Rb-88

Rb-87

898

(91)

108 d

Y-88

Y-89,

898

(0.06)

6.5 h

Cd-107

Cd-108

6.0 E-5

898

(0.3)

150 a

Tb-158

Tb-159

6.6 E-7

899

(1)

23.6 h

Hf-173

Hf-174

1.9 E-4

899

(0.6)

1.9 h

Yb-177

Yb-176

1 . 1 E-4

899

(99)

66.9 m

Pb-204m

Pb-206

3 . 8 E-2

901

(28)

6.7 d

Lu-172

Lu-175

2 . 8 E-3

903

(38)

38 d

Re-184

Re-185

7.6 E-2

9 06

(2)

17 h

Ce-135

Ce-136

7.4 E-4

906

(2)

9.59 h

Dy-155

Dy-156

3 . 0 E-4

906

(0.2)

32.06 h

Cs-129

Ba-130

2.6 E-5

907

(0.09)

36 h

Ni-57

Ni-58

9 . 0 E-4

908

(0.4)

33 h

Sr-83

Sr-84

1 . 1 E-4

908

(?)

20 h

Rh-100

Pd-102

?

908

(0.6)

7.5 h

Er-171

Er-170

1.5 E-4

909

(1)

3.3 h

Cu-61

Cu-63

1.2 E-2

909

(99)

16 s

Y-89m

Zr-90, Y-89

5.1

909

(99)

78.4 h

Zr-89

Zr-90

1.6

910

(0.07)

154 d

Te-121m

Te-122

5.3 E-7

1.4 E-2 Zr-90

1.0 E - l

911

(0.07)

9.5 h

Hg-195

Hg-196

5.4 E - 5

912

(96)

66.9 m

Pb-204m

Pb-206

3.5 E-2

912

(2)

10.5 d

Nb-92m

Nb-93, Mo-94

1.1 E-2

912

(1)

63.6 h

Tm-172

Yb-173

5 . 5 E-5

912

(15)

6.7 d

Lu-172

Lu-175

1 . 5 E-3

913

(0.04)

39 h

Ge-69

Ge-70, S e - 7 4

4.8 E-4

913

(6)

4.7 d

Te-119m

Te-120

2.3 E - 5

914

(13)

5.37 d

Pm-148

Sm-149

2.9 E-4

915

(0.08)

8.47 h

Pd-101

Pd-102

6 . 7 E-2

915

(21)

4.32 h

Sb-129

Te-130

7 . 0 E-3

915

(19)

41.3 d

Pm-148m

Sm-149

3.8 E-5

915

(2)

54 d

Eu-148

Eu-151

8.3 E-6

915

(3)

93.1 d

Tm-168

Tm-169

5 . 1 E-3

Ru-96

3 . 5 E-3

Ce-138

4 . 5 E-5

916

(7)

4.9 h

Tc-94

916

(0.07)

9 h

Ce-137

273 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

916

(0.2)

18.7 m

Eu-159

Gd-160

8.3 E-4

917

(0.1)

33 h

Sr-83

Sr-84

2.8 E - 5

919

(56)

19 m

Y-94

Zr-96

1.7 E - l

920

(2)

40.2 h

La-140

La-139

2.4 E-4

920

(0.1)

17.7 m

Yb-167

Yb-168

9.2 E-4

921

(8)

165 d

Re-184m

Re-185

·>

922

(0.2)

12.6 h

Eu-150m

Eu-151

1.2 E-2

924

(0.5)

3.85 d

Sb-127

Te-128

7.5 E - 5

924

(0.7)

11.5 d

Ba-131

Ba-132

1.0 E-5

925

(99)

69.2 h

Ag-104

Cd-106

8.3 E - 4

925

(7)

40.2 h

La-140

La-139

8.4 E-4

928

(1)

15.97 d

V-48

C r - 5 0 , V-50

3.2 E - 6

928

(0.6)

115 d

Ta-182

VV-183, Ta-181

1.4 E - 5

Dy-155

Dy-156

9.5 E-5

929

(0.6)

9.59 h

929

(3)

6.7 d

Lu-172

Lu-175

2.9 E - 4

931

(0.6)

16.8 h

Re-188

Re-187, Os-189

3 . 6 E-3

931

(0.03)

206 d

Rh-102

Rh-103,, Pd-104

1.4 E - 5

931

(2)

54 d

Eu-148

Eu-151

8.3 E-6

931

(0.05)

94 d

Os-185

Os-186

1.8 E - 6

931

(0.5)

9.5 h

Hg-195

Hg-196

3.8 E-4

932

(2)

3.1 h

Er-161

Er-162

4.2 E - 3

934

(1)

55 m

Cd-105

Cd-106

5.5 E - 4

934

(2)

44.8 d

Cd-115m

Cd-116

4.8 E-6

935

(14)

3.54 h

Y-92

Zr-94

1.4 E-3

935

(99)

10.5 d

Nb-92

Nb-93, Mo-94

5.4 E - l

935

(6)

2.13 h

Ba-129m

Ba-130

1.3 E-3

936

(84)

5.7 d

Mn-52

Fe-54

1.4 E-4

936

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E-3

937

(34)

250.4 d

Ag-110m

Ag-109,, Cd-111

1.5 E - 5

937

(70)

4.9 h

In-110m

Sn-112

7.7 E-3

937

(11)

68 m

Ho-162m

Ho-165

4 . 0 E-2

939

(0.6)

19.4 h

Ir-194

I r - 1 9 3 , Pt-195

5.5 E - 4

939

(1)

39.5 h

Au-194

Au-197

7.6 E - 4

940

(0.3)

9.59 h

Dy-155

Dy-156

4.5 E-5

941

(0.1)

3.1 h

Er-161

Er-162

2.1 E-4

941

(14)

15.2 m

Tm-175

Yb-176

4.2 E-2

942

(38)

21.1 h

Mg-28

Si-30

w

T a b . 5 - 5 , continued Ε, keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

942

(5)

5 h

Mo-90

Mo-9 2

7.5 E - 4

942

(25)

69.2 h

Ag-104

Cd-106

2.3 E-4

942

(5)

4.7 d

Te-119m

Te-120

2.0 E - 5

942

(1)

1.9 h

Yb-177

Yb-176

1.8 E-4

944

(9)

15.97 d

V-48

C r - 5 0 , V-50

3.6 E - 5

944

(1)

15.2 d

Eu-156

Gd-157

9.3 E-6

944

(43)

150 a

Tb-158

Tb-159

9 . 5 E-5

945

(0.2)

33 h

Sr-83

Sr-84

5.6 E-5

947

(2)

10.1 h

Y-93

Zr-94

2.2 E - 3

948

(2)

20 h

Tc-95

Ru-96

1.6 E-2

948

(0.9)

55 m

Cd-105

Cd-106

5.0 E - 6

948

(2)

39.5 h

Au-194

Au-197

1.5 E - 3

951

(0.6)

40.2 h

La-140

La-139

7.2 E - 5

953

(19)

10.3 m

Y-95

Zr-96

7.7 E - l

9 54

(0.2)

35.3 m

Sn-111

Sn-112

2.8 E-3

955

(2)

10 h

Os-183m

Os-184

2.0 E - 4

9 57

(5)

2.13 h

Ba-129m

Ba-130

1.0 E - 3

960

(0.4)

115 d

Ta-182

VV-183, Ta-181

1.0 E-5

(1)

15.2 d

Eu-156

Gd-157

9.4 E-6

960 960

(0.3)

12.2 d

Tl-202

Tl-203

4 . 3 E-4

961

(0.1)

66 h

Mo-99

Mo-100

3.1 E-4

961

(92)

3.62 h

Pb-202m

Pb-204

2.5 E - 4

962

(5)

55 m

Cd-105

Cd-106

2.7 E-3

9 62

(7)

38.4 m

Zn-63

Zn-64

7.3

962

(20)

150 a

Tb-158

Tb-159

4.4 E-5

962

(9)

72.1 d

Tb-160

T b - 1 5 9 , , Dy-161

3.9 E-4

962

(18)

5 h

Ho-160m

Er-162

?

962

(0.2)

3.1 h

Er-161

Er-162

4.2 E-4

9 63

(12)

9.3 h

Eu-152m2

Eu-153

9 . 0 E-2

964

(14)

12.4 a

Eu-152

Eu-153

1.1 E - 4

965

(0.3)

17 h

Ce-135

Ce-136

1.1 E - 4

965

(0.02)

8.47 h

Pd-101

Pd-102

1.7 E-2

966

(25)

72.1 d

Tb-160

T b - 1 5 9 , , Dy-161

966

(16)

5 h

Ho-160m

Er-162

1.1 E-3 ?

966

(8)

4.32 h

Sb-129

Te-130

2.7 E-3

967

(3)

54 d

Eu-148

Eu-151

1.2 E-5

968

(0.2)

6.7 d

Lu-172

Lu-175

1.9 E-5

275 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

971

(1)

14.1 h

Ga-72

Ge-73, Ga-71

1.3 E-3

973

(0.3)

3.1 h

Er-161

Er-162

6.3 E-4

975

(15)

59.6 s

Na-25

Mg-26

5.4 E - l

976

(3)

4.7 d

Te-119m

Te-120

1.2 E - 5

977

(1)

77.3 d

Co-5 6

Ni-58

1.3 E - 5

979

(3)

4.7 d

Te-119

Te-120

1.2 E - 5

980

(0.3)

3.1 h

Er-161

Er-162

6.3 E-4

982

(0.02)

2.5 h

Nd-141

Nd-142

3.2 E-3

982

(0.3)

9.59 h

Dy-155

Dy-156

4.5 E-5

982

(0.02)

69.6 m

Te-129

Te-130

3 . 8 E-3

982

(26)

5.5 h

Nd-139m

Nd-142

6.0 E-5

982

(11)

15.2 m

Tm-175

Yb-176

3.3 E-2

983

(100)

15.97 d

V-48

C r - 5 0 , V-50

3.2 E - 4

984

(100)

43.67 h

Sc-48

Ti-49

3 . 1 E-2

986

(82)

43 s

V-54

Cr-54

w

987

(0.2)

55 m

Cd-105

Cd-106

1.1 E-4

988

(0.9)

41.5 h

Ir-188

Ir-189

6.8 E-6

989

(0.1)

15.9 m

Sb-120

Sb-121

7.6 E - l

989

(0.3)

22.2 h

K-43

Ca-44

·>

989

(0.4)

5.37 h

Ag-113

Cd-114

2.1 E - 4

989

(0.01)

9.5 h

Hg-195

Hg-196

7.6 E-6

990

(1)

5 h

Mo-90

Mo-92

1.5 E-4

990

(0.6)

1.65 h

Ru-95

Ru-96

1.0 E - l

992

(0.7)

142 d

Lu-174m

Lu-175

6.1 E-5

993

(0.07)

8.2 m

As-79

Se-80

9.1 E-4

993

(1)

8.47 h

Pd-101

Pd-102

8 . 4 E-3

994

(0.3)

39 m

Se-73m

Se-74

9.6 E-3

994

(0.02)

17.77 d

As-74

As-75, Se-76,

994

(0.7)

33 h

Sr-83

Sr-84

2.0 E-4

996

(10)

8.5 a

Eu-154

Eu-153, Gd-155

1.9 E-5

998

(0.4)

55 m

Cd-105

Cd-106

2.2 E-4

1000

(0.8)

14.1 h

Ga-72

Ge-73, Ga-71

1.1 E-3

1000

(8)

2.13 h

Ba-129m

Ba-130

1.7 E-3

1000

(3)

9.59 h

Dy-155

Dy-156

4.5 E-5

1002

(1)

2.44 d

Sc-44m

Sc-45, Ti-46

1.6 E-3

1002

(2)

115 d

Ta-182

W-183, Ta-181

4 . 8 E-5

1003

(0.2)

39 m

Se-73m

Se-74

6 . 4 E-3

Br-79

1 . 4 E-4

T a b . 5 - 5 , continued E . k e V (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

1003

(1)

72.1 d

Tb-160

T b - 1 5 9 , , Dy-161

4.3 E-5

1003

(5)

6.7 d

Lu-172

Lu-175

4 . 8 E-4

1005

(17)

8.5 a

Eu-154

Eu-153, Gd-155

3.2 E-5

1005

(1)

56 h

Br-77

Br-79

2.2 E - 3

1006

(89)

1.6 m

V-53

Cr-54

3.5 E - l

1007

(10)

3m

Cu-69

Zn-70

3.3 E-3

1007

(0.2)

55 m

Cd-105

Cd-106

8 . 8 E-5

1009

(0.03)

9.5 h

Hg-195

Hg-196

2.3 E - 5

1011

(0.7)

1.65 h

Ru-95

Ru-96

1.2 E - l

1011

(0.07)

3.1 h

Er-161

Er-162

1.5 E - 4

1012

(86)

2.5 m

Fe-53m

F e - 5 4 , Ni-58

1.4 E - 3

1012

(13)

14.6 m

Mo-101

Mo-100

7 . 3 E-3

1013

(2)

4.7 d

Te-119m

Te-120

7.8 E - 6

1013

(0.3)

9.59 h

Dy-155

Dy-156

4.5 E - 5

1014

(20)

43.3 d

Pm-148m

Sm-149

4.0 E-5

1015

(30)

9.46 m

Mg-27

Al-27

7 . 2 E-2

1015

(0.02)

8.47 h

Pd-101

Pd-102

1.7 E-2

1015

(0.5)

18.7 m

Eu-159

Gd-160

2.1 E-3

1016

(0.5)

34.5 d

Rb-84

Rb-85, Sr-86

1.3 E - 3

1019

(8)

6.24 d

Bi-206

Bi-209

2.3 E - 4

1020

(1)

8.3 d

Ag-106m

Ag-107

4.2 E-4

1020

(0.1)

6.46 m

Br-78

Br-79

5.2 E + l

1020

(0.07)

33 h

Sr-83

Sr-84

2.0 E-5

1021

(0.07)

3.1 h

Er-161

Er-162

1.4 E-4

1021

(0.2)

9.5 h

Hg-195

Hg-196

1.5 E - 4

1022

(3)

22.2 h

K-43

Ca-44

1.2 E - 3

1022

(1)

6.7 d

Lu-172

Lu-175

9.4 E-5

1023

(100)

5.76 d

Sb-120m

Sb-121

7.5 E - 2

1023

(0.02)

33.6 d

Te-129m

Te-130

1.4 E - 5

1023

(0.5)

38 d

Re-184

Re-185

9 . 8 E-4

1024

(36)

9.5 h

Sr-91

Zr-96

w

1025

(1)

74 m

Nb-97

Mo-98

1.9 E-2

1025

(0.9)

35 h

Sn-111

Sn-112

1.3 E-2

1028

(0.6)

1.90 h

Yb-177

Yb-176

1.1 E-4

1030

(13)

4.32 h

Sb-129

Te-130

4.3 E-3

1031

(0.1)

6.47 d

Cs-132

Cs-133

2.4 E-3

1032

(0.2)

55 m

Cd-105

Cd-106

1.1 E - 4

277 T a b . 5 - 5 , continued Nuclide

Target Nuclide

Ν · I

Rh-100

Pd-102

5.2 E - 4

Eu-148

Eu-151

3.3 E - 5

Ba-129m

Ba-130

1.9 E-3

10 h

Os-183m

Os-184

7 . 0 E-4

12.1 d

Ir-190

Ir-191

1.4 E - 2

Sr-84

2.8 E-5

E.keV (1%)

Τ

1034

(2)

20 h

1034

(8)

54 d

1035

(9)

2.13 h

1035

(7)

1036

(2)

1037

(0.1)

33 h

Sr-83

1037

(0.6)

17.7 m

Yb-167

Yb-168

5 . 4 E-3

1037

(0.8)

23.6 h

Hf-173

Hf-174

1.5 E-4

1038

(98)

43.67 h

Sc-48

Ti-49

3.1 E-2

1038

(0.04)

17 h

Ce-135

Ce-136

1.5 E-5

1038

(14)

77.3 d

Co-56

Ni-58

1.8 E - 4

1038

(0.6)

55 m

Cd-105

Cd-106

3.3 E - 4

1038

(100)

2.02 h

Pr-138m

Pr-141

w

1038

(0.2)

18.7 m

Eu-159

Gd-160

8 . 2 E-4

1039

(9)

5.1 m

Cu-66

Cu-65, Zn-67, Ga-71

1.4 E - l

1039

(0.5)

21.1 m

Ga-70

Ga-71, Ge-72, As-75

2 . 8 E-2

1039

(3)

60 d

Tc-95m

Ru-96

4 . 8 E-5

1041

(0.6)

6.7 d

Lu-172

Lu-175

5.8 E-5

1041

(0.3)

10 h

Os-183m

Os-184

3.0 E-5

1042

(0.06)

8.47 h

Pd-101

Pd-102

5.0 E - 2

1043

(1)

55 m

Cd-105

Cd-106

5.5 E-5

1044

(9)

35.34 h

Br-82

B r - 8 1 , Rb-87

1.5 E-3

1044

(33)

6.3 h

Rb-82m

Sr-84

2 . 0 E-3

1044

(0.4)

33 h

Sr-83

Sr-84

1 . 1 E-4

1044

(0.5)

18.7 m

Eu-159

Gd-160

2 . 1 E-3

1044

(0.2)

115 d

Ta-182

W-183, Ta-181

4.8 E-6

1045

(16)

2.13 h

Ba-129m

Ba-130

3.4 E-3

1046

(30)

8.3 d

Ag-106m

Ag-107

1.2 E - 2

1046

(0.1)

36 h

Ni-57

Ni-58

1.0 E - l

1047

(31)

2.2 h

Rh-106m

Pd-108

2.0 E - l

1047

(0.4)

206 d

Rh-102

Rh-103,, Pd-104

1.9 E-4

1047

(34)

2.9 a

Rh-102m

Rh-103,, Pd-104

2.9 E-4

1048

(3)

4.7 d

Te-119m

Te-120

1.2 E-5

1048

(80)

13 d

Cs-136

Ba-137

8 . 8 E-4

1048

(1)

11.5 d

Ba-131

Ba-132

1.5 E-5

1048

(0.08)

3.1 h

Er-161

Er-162

1.7 E-4

1049

(5)

6 a

Eu-150

Eu-151

7.2 E-6

T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

1049

(0.9)

39.4 h

Au-194

Au-197

6.8 E-4

1049

(0.02)

9.5 h

Hg-195

Hg-196

1.5 E-5

1050

(0.2)

24 m

Ag-106

Ag-107,, Cd-108

2.2

1050

(0.02)

33.6 d

Te-129m

Te-130

1.4 E - 5

1051

(82)

4.4 m

In-118m

Sn-119

3.7 E-3

1051

(7)

14.1 h

Ga-72

Ge-73, Ga-71

9 . 1 E-3

1051

(1)

26 h

As-72

Se-74

1.0 E - 5

1051

(3)

1.65 h

Ru-95

Ru-96

5.2 E - l

1052

(0.07)

17 h

Ce-135

Ce-136

2.6 E-5

1052

(0.3)

39 h

Ge-69

Ge-70, S e - 7 4

3.6 E-3

1055

(0.2)

33 h

Sr-83

Sr-84

5.6 E - 5

1057

(2)

8.83 m

Sm-143

Sm-144

3.8 E - l

1060

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E - 3

1062

(0.4)

9.59 h

Dy-155

Dy-156

6.0 E-5

1064

(0.7)

1.65 h

Ru-95

Ru-96

1.2 E - l

1064

(74)

38 a

Bi-207

Bi-209

2.0 E - 4 4.7 E - 5

1065

(5)

15.2 d

Eu-156

Gd-157

1065

(11)

5.35 d

Tb-156

Tb-159

1.4 E - 4

1065

(0.1)

3.1 h

Er-161

Er-162

2.1 E-6

1067

(0.6)

7.6 m

Tb-162

Dy-163

2.0 E - 3

1068

(0.5)

9.59 h

Dy-155

Dy-156

7.2 E-5

1069

(0.1)

72.1 d

Tb-160

T b - 1 5 9 , , Dy-161

4.3 E-6

1069

(3)

5 h

Ho-160m

Er-162

?

(1)

55 m

Cd-105

Cd-106

5.7 E-4 3.2 E - 2

1072 1074

(4)

20 h

Tc-95

Ru-96

1077

(9)

18.7 d

Rb-86

Rb-87, Sr-87

1.8 E-2

1078

(100)

30 s

Cu-68

Zn-70

3 . 1 E-2

1078

(3)

68.3 m

Ga-68

Ga-69, Ge-70

2.7

1078

(2)

39 m

Se-73m

Se-74

6 . 4 E-2

1078

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E - 3

1078

(0.08)

3.1 h

Er-161

Er-162

1.7 E - 4

1079

(4)

15.2 d

Eu-156

Gd-157

3.8 E-5

1080

(2)

1.5 h

As-78

Se-80

4.4 E-4

1080

(0.09)

2.35 h

Dy-165

Dy-164

8.6 E-4

1080

(5)

1.9 h

Yb-177

Yb-176

9.5 E-4

1081

(2)

4.7 d

Te-119m

Te-120

7.8 E-6

1081

(1)

6.7 d

Lu-172

Lu-175

9 . 6 E-5

279

T a b . 5-5, continued Τ

Nuclide

Target Nuclide

Ν ' I

9.5 h

Hg-195

Hg-196

6.2 E-5

69.6 m

Te-129

Te-130

1.2 E-2

40.3 h

La-140

La-139

9

12.4 a

Eu-152

Eu-153

8.3 E-5

(0.1)

39 m

Se-73m

Se-74

3.2 E-2

1088

(0.2)

2.965 d

Au-198

Au-197, Hg-199

1.8 E-4

1088

(4)

41.2 d

Ag-105

Ag-107, Cd-106

1.0 E-3

1089

(0.6)

129.2 d

Sn-123

Sn-124

1.4 E-5

1090

(3)

10.5 m

Yb-165

Yb-168

3.6 E-3

E.keV (1%) 1083

(0.08)

1084

(0.6)

1085

(?)

1086

(10)

1087

1090

(2)

12.4 a

Eu-152

Eu-153

1.6 E-5

1090

(3)

9.59 h

Dy-155

Dy-156

4.5 E-4

1091

(?)

2.58 h

Mn-56

Mn-55, Fe-57

·>

1091

(0.2)

6.2 d

Au-196

Au-197

5.2 E-3

1091

(49)

23.4 h

Nb-96

Mo-97

3.8 E-2

1094

(63)

6.7 d

Lu-172

Lu-175

6.1 E-3

1094

(6)

63.6 h

Tm-172

Yb-173

3.3 E-4

1095

(1)

18.7 m

Eu-159

Gd-160

4.1 E-3

1096

(2)

4.7 d

Te-119m

Te-120

7.8 E-6

1097

(3)

4.4 m

In-118m

Sn-119

1.4 E-4

1097

(22)

1.65 h

Ru-95

Ru-96

3.7

1097

(56)

54 m

In-116ml

In-115, Sn-117

5.1

1097

(1)

41.5 h

Ir-188

Ir-191

8.0 E-6

1098

(0.3)

33 h

Sr-83

Sr-84

8.4 E-5

1098

(0.2)

3.1 h

Er-161

Er-162

4.2 E-4

1098

(13)

6.24 d

Bi-206

Bi-209

3.8 E-4

1099

(56)

44.6 d

Fe-59

Fe-58, Ni-64

w

1100

(0.3)

3.3 h

Cu-61

Cu-63

3.6 E-3

1101

(0.01)

17.77 d

As-74

As-75, Se-76, Br-79

6.8 E-5

1102

(2)

154 d

Te-121m

Te-122

1.5 E-5

1102

(55)

10 h

Os-183m

Os-184

5.5 E-3

1103

(3)

206 d

Rh-102

Rh-103, Pd-104

1.4 E-3

1103

(0.6)

72.1 d

Tb-160

Tb-159, Dy-161

2.6 E-5

1104

(0.4)

3.2 h

Ag-112

Cd-113

6.4 E-5

1104

(2)

39.5 h

Au-194

Au-197

1.6 E-3

1106

(0.6)

16 h

Te-119

Te-120

3.1 E-5

1106

(0.5)

9.25 m

Ta-178

Ta-180, W-180

1.1 E-3

Cl-35

?

1107

(?)

62 m

Cl-34m

280

T a b . 5-5, continued E.keV ' (1%)

Τ

Nuclide

Target Nuclide

1107

(28)

39 h

Ge-69

Ge-70, Se-74

3.3 E - l

1107

(15)

20 h

Rh-100

Pd-102

3.9 E-3

1108

(2)

150 a

Tb-158

Tb-159

4.4 E-6

1108

(25)

10 h

Os-183m

Os-184

2.6 E-3

1109

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E-3

1111

(0.2)

7.1 h

Se-73

Se-74

3.0 E-4

1111

(2)

9.5 h

Hg-195

Hg-196

1.6 E-3

1112

(0.2)

69.6 m

Te-129

Te-130

3.8 E-2

Ν ' I

1112

(0.2)

33.6 d

Te-129m

Te-130

1.5 E-4

1112

(13)

12.4 a

Eu-152

Eu-153

1.1 E-4

1113

(17)

2.9 a

Rh-102m

Rh-103 , Pd-104

1.4 E-4 6.8 E-4

1113

(0.9)

5.76 d

Sb-120m

Sb-121

1113

(2)

6.7 d

Lu-172

Lu-175

1.9 E-4

1113

(0.4)

115 d

Ta-182

W-183, Ta-181

9.6 E-6

1115

(1)

72.1 d

Tb-160

Tb-159 , Dy-161

4.3 E-5

1115

(0.4)

9.59 h

Dy-155

Dy-156

6.0 E-5

1116

(51)

244 d

Zn-65

Zn-66, Ge-70

7.2 E-3

1117

(0.1)

74 m

Nb-97

Mo-98

1.9 E-3

1118

(0.2)

3.1 h

Er-161

Er-162

4.2 E-4

1120

(0.9)

1.65 h

Ru-95

Ru-96

1.5 E - l

1120

(0.02)

22 m

Rh-107

Pd-108

1.1 E-4

1121

(0.2)

16 h

Te-119

Te-120

1.0 E-5

1121

(100)

84 d

Sc-46

Ti-47, Sc-45

2.1 E-3

1121

(100)

1.7 m

Sc-50

Ti-50

w

1121

(35)

115 d

Ta-182

VV-183, Ta-181

8.4 E-4

1121

(32)

13 h

Re-182m

Re-185

?

1121

(21)

64 h

Re-182

Re-185, Os-184

4.2 E-4

1122

(0.6)

8.3 d

Ag-106m

Ag-107

2.5 E-4

1122

(7)

2.13 h

Ba-129m

Ba-130

1.5 E-3

1125

(1)

68 m

Ho-162m

Ho-165

3.6 E-3

1126

(0.03)

2.7 d

Sb-122

Sb-123, Te-123

7.8 E-4

1126

(1)

2.44 d

Sc-44m

Sc-45, Ti-46

1.6 E-3

1127

(0.5)

23.4 h

Nb-96

Mo-97

3.9 E-4

1127

(0.7)

2.5 h

Nd-141

Nd-142

1.1 E - l

1128

(0.1)

24 m

Ag-106

Ag-107,, Cd-108

1.1

1128

(12)

8.3 d

Ag-106m

Ag-107

5.1 E-3

1128

(14)

2.2 h

Rh-106m

Pd-108

9.0 E-2

281

T a b . 5-5, continued E.keV (1%) 1128

(0.5)

Τ

Nuclide

Target Nuclide

Ν ' I

18.7 m

Eu-159

Gd-160

2.1 E-3

1129

(93)

14.6 h

Nb-90

Mo-92

3.5 E-2

1130

(0.1)

26.4 h

As-76

As-75, Se-77

1.6 E-4

1132

(0.09)

16.98 h

Re-188

Re-187, Os-189

5.3 E-4

1134

(0.4)

12.1 d

Ir-190

Ir-191

2.8 E-3

1136

(0.5)

6.47 d

Cs-132

Cs-133

1.2 E-2

1137

(8)

4.7 d

Te-119m

Te-120

3.1 E-5

1139

(0.09)

17 h

Ce-135

Ce-136

3.3 E-5

Sb-123, Te-123

2.1 E-2

1141

(0.8)

2.7 d

Sb-122

1142

(0.4)

3.85 d

Sb-127

Te-128

6.1 E-5

1145

(?)

7.7 m

K-38

K-39, Ca-40

?

1145

(2)

1.5 h

As-78

Se-80

4.4 E-4

1145

(0.7)

3.1 h

Er-161

Er-162

1.5 E-3

1145

(0.5)

6.7 d

Lu-172

Lu-175

4.8 E-5

1147

(0.3)

2.5 h

Nd-141

Nd-142

4.8 E-2

1148

(1)

33 h

Sr-83

Sr-84

2.8 E-4

1149

(0.05)

74 m

Nb-97

Mo-98

9.5 E-4

1149

(0.04)

22 m

Rh-107

Pd-108

2.2 E-4

1149

(0.2)

17 h

Ce-135

Ce-136

2.6 E-4

1150

(0.04)

39 h

Ge-69

Ge-70, Se-74

4.8 E-4

1151

(0.6)

19.4 h

Ir-194

Ir-193, Pt-195

5.6 E-4

1151

(1)

39.5 h

Au-194

Au-197

7.9 E-4

1152

(1)

35.3 m

Sn-111

Sn-112

1.4 E-2

1153

(0.2)

6.7 d

Lu-172

Lu-175

1.9 E-5

1154

(12)

15.2 d

Eu-156

Eu-157

1.2 E-4

1154

(11)

5.35 d

Tb-156

Tb-159

1.3 E-4

1155

(0.2)

20 h

Rh-100

Pd-102

3.9 E-5

1155

(0.4)

3.85 d

Sb-127

Te-128

6.5 E-5

1155

(2)

9.59 h

Dy-155

Dy-156

2.9 E-4

1157

(58)

22.2 m

K-44

Ca-46

w

1157

(94)

3.92 h

Sc-44

Sc-45, Ti-46

2.4 E+l

1157

(1)

2.44 d

Sc-44m

Sc-45, Ti-46

1.6 E-3

1157

(1)

115 d

Ta-182

W-183, Ta-181

2.4 E-5

1158

(1)

1.65 h

Ru-95

Ru-96

1.7 E - l

1158

(0.6)

206 d

Rh-102

Rh-103, Pd-104

2.8 E-4

1159

(0.5)

3.1 h

Er-161

Er-162

1.1 E-3

1160

(2)

33 h

Sr-83

Sr-84

5.6 E-4

T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

1163

(1)

14 h

Os-183

Os-184

2.7 E-5

1164

(71)

14 m

Co-6 2

Ni-64

3.2 E-3

1164

(?)

14.6 h

Nb-90

Mo-9 2

•>

1164

(0.01)

8.47 h

Pd-101

Pd-102

8 . 5 E-3

1165

(9)

2.13 h

Ba-129m

Ba-130

1.8 E-3

(0.2)

12.6 h

Eu-150m

Eu-151

1.2 E-2

1166 1166

(0.1)

6.7 d

Lu-172

Lu-175

9 . 5 E-6

1167

(2)

9.59 h

Dy-155

Dy-156

3.0 E-4

1169

(18)

51 m

Nb-98

Mo-100

9 . 7 E-4

1171

(0.4)

17 h

Ce-135

Ce-136

1.5 E-4

1171

(1)

36 a

Eu-150

Eu-151

1.4 E-6

1172

(2)

15.9 m

Sb-120

Sb-121

1.5 E + l

1172

(100)

5.76 d

Sb-120m

Sb-121

7 . 5 E-2

1172

(0.2)

6.7 d

Lu-172

Lu-175

1.9 E - 5

1172

(1)

9.5 h

Hg-195

Hg-196

7.9 E-4

1173

(100)

5.272 a

Co-60

Ni-61, Co-59, Cu-65

1.4 E-4

1173

(100)

14 m

Co-62

Ni-64

4 . 5 E-3

1173

(0.4)

9.76 m

Cu-62

Cu-63, Zn-64

3.1

(9)

4.4 m

In-118m

Sn-119

4.6 E - 5

1173

(0.5)

8.83 m

Sm-143

Sm-144

9 . 6 E-2

1174

(2)

3.1 h

Er-161

Er-162

4 . 2 E-3

1175

(2)

39.5 h

Au-194

Au-197

1.5 E-3

1177

(0.7)

16 h

Te-119

Te-120

3.6 E - 5

1177

(8)

7.7 h

Tm-166

Tm-169

2.8 E - 4 1.1

1173

1178

(12)

32 m

Cl-34m

Cl-35, K-39

1178

(0.3)

8.47 h

Pd-101

Pd-102

2.5 E - l

1178

(15)

72.1 d

Tb-160

Tb-159, , Dy-161

6 . 5 E-4

1179

(5)

1.65 h

Ru-95

Ru-96

1180

(?)

14.1 h

Ga-72

Ge-73, Ga-71

8.5 E-l 9

1182

(0.1)

18.7 m

Eu-159

Gd-160

4 . 1 E-4

1183

(0.2)

9.25 m

Ta-178

Ta-180

·?

1184

(1)

17 h

Ce-135

Ce-136

3.7 E-4

1184

(0.5)

6.7 d

Lu-172

Lu-175

4.8 E-5

1184

(0.3)

19.4 h

Ir-194

I r - 1 9 3 , Pt-195

2.8 E-4

1184

(0.6)

39.5 h

Au-194

Au-197

4.6 E-4

1185

(4)

3.3 h

Cu-61

Cu-63

4.8 E-2

1186

(0.7)

3.1 h

Er-161

Er-162

1.5 E-3

283 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

1187

(2)

150 a

Tb-158

Tb-159

4.4 E-6

1189

(6)

115 d

Ta-182

VV-183, Ta-181

3.8 E-4

1189

(0.02)

9.5 h

Hg-195

Hg-196

1.5 E - 5

1193

(0.6)

3.1 h

Er-161

Er-162

1.3 E-3

1194

(0.02)

12.6 h

Eu-150m

Eu-151

1.2 E-3

1195

(0.4)

5.37 h

Ag-113

Cd-114

2 . 1 E-4

1196

(1)

53 m

Tc-94m

Ru-96

7 . 6 E-5

1199

(1)

1.5 h

As-78

Se-80

2.2 E - 4

1199

(11)

8.3 d

Ag-106m

Ag-107

4.2 E-2

1199

(1)

5 h

Ho-160m

Er-162

·>

1200

(2)

72.1 d

Tb-160

Tb-159, , Dy-161

8 . 5 E-5

1200

(0.4)

12.1 d

Ir-190

Ir-191

2.8 E-3

1200

(20)

23.4 h

Nb-96

Mo-9 7

1 . 5 E-2

1202

(0.2)

33 h

Sr-83

Sr-84

5.5 E-5

1202

(1)

8.47 h

Pd-101

Pd-102

8.5 E - l

1204

(0.3)

17.77 d

As-74

As-75, Se-76, Br-79

2 . 0 E-3

1205

(3)

62 d

Nb-91m

Mo-92, Nb-93

6.3 E-3

1206

(0.3)

23.6 h

Hf-173

Hf-174

5.6 E-5

1206

(0.3)

39 h

Ge-69

Ge-70, S e - 7 4

3.6 E-3

1206

(30)

26.1 h

Tl-200

Tl-203

2.6 E-5

1207

(?)

6.24 d

Bi-206

Bi-209

·>

1208

(0.3)

58.5 d

Y-91

Zr-92

1.4 E-4

1208

(19)

65 s

Mo-91m

Mo-92

2.7

1209

(9)

2.13 h

Ba-129m

Ba-130

1.9 E-3 8.4 E-4

1210

(0.4)

3.1 h

Er-161

Er-162

1210

(7)

41.5 h

Ir-188

Ir-191, Pt-190

5.4 E - 5

1211

(0.2)

55 m

Cd-105

Cd-106

1 . 1 E-4

1213

(2)

43.64 h

Sc-48

Ti-49

6.2 E-4

1213

(2)

26.4 h

As-76

A s - 7 5 , Se-77

2.6 E-3

1213

(66)

4.7 d

Te-119m

Te-120

2.6 E-4

1213

(1)

12.4 a

Eu-152

Eu-153

8 . 2 E-6

1214

(0.1)

17 h

Ce-135

Ce-136

3.7 E - 5

1215

(0.3)

33 h

Sr-83

Sr-84

8.3 E-5

1216

(3)

26.4 h

As-76

A s - 7 5 , Se-77

3.9 E-3

1218

(0.3)

35.3 m

Sn-111

Sn-112

4 . 2 E-3

1218

(0.5)

8.47 h

Pd-101

Pd-102

4.2 E - l

1219

(1)

39.5 h

Au-194

Au-197

7.6 E-4

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

Ho-165

8 . 3 E-2

1220

(23)

68 m

Ho-162

1221

(0.2)

18.7 m

Eu-159

Gd-160

8 . 2 E-4

1221

(7)

115 d

Ta-182

YV-183, T a - 1 8 1

6.4 E-4

1222

(9)

2.13 h

Ba-129m

Ba-130

1.9 E-3

1222

(32)

5.35 d

Tb-156

Tb-159

3.8 E-4

1222

(7)

64 h

Re-182

Re-185, Os-184

3.4 E-4

1223

(7)

8.3 d

Ag-106m

Ag-107

3 . 0 E-3

1223

(4)

(20.9 m)

Pm-141

Sm-144

?

1223

(0.2)

12.6 h

Eu-150m

Eu-151

1.2 E-2

1224

(0.1)

36 h

Ni-57

Ni-58

1.7 E-3

1226

(15)

48.4 m

Au-200

Hg-201

4 . 8 E-3

1228

(0.1)

3.1 h

Er-161

Er-162

2 . 1 E-4

1229

(0.2)

55 m

Cd-105

Cd-106

1.1 E-4

1229

(1)

26.4 h

As-76

A s - 7 5 , Se-77

1.3 E-3

1230

(96)

4.4 m

In-118m

Sn-119

4.4 E-3

(1)

14.1 h

Ga-72

Ge-73, Ga-71

1 . 5 E-3 7.6 E-5

1231 1231

(8)

15.2 d

Eu-156

Gd-157

1231

(4)

64 h

Re-182

Re-185, Os-184

2.8 E-4

1231

(12)

115 d

Ta-182

VV-183, T a - 1 8 1

2.9 E-4

1233

( 0 . 0 0 9 ) 69.6 m

Te-129

Te-130

1.7 E-3

1233

(0.1)

17 h

Ce-135

Ce-136

3.8 E-5

1234

(0.7)

36 m

Er-159

Er-162

w

1237

(0.1)

42 s

Rh-104

Rh-103, , Pd-105

1.3 E - l

1238

(68)

77.3 d

Co-5 6

Ni-58

8.9 E-4

1238

(0.3)

33 h

Sr-83

Sr-84

8.5 E-5

1239

(3)

33.5 m

Ag-104m

Cd-106

3.9 E-4

1239

(0.09)

3.1 h

Er-161

Er-162

1.9 E-4

1240

(0.3)

55 m

Cd-105

Cd-106

1.7 E-4

1240

(6)

1.5 h

As-78

Se-80

1.3 E-3

1241

(3)

1.9 h

Yb-177

Yb-176

5.7 E-4

1242

(7)

15.2 d

Eu-156

Gd-157

6.5 E-5

1242

(6)

3.31 a

Lu-174

Lu-175

3.8 E-4

1243

(0.09)

33 h

Sr-83

Sr-84

1243

(?)

72.5 m

Sm-142

Sm-144

2.5 E - 5 ?

1247

(0.7)

40 h

Hg-195m

Hg-196

1.6 E-5

1247

(5)

5.7 d

Mn-52

Fe-54

8 . 5 E-6

1247

(0.3)

3.1 h

Er-161

Er-162

6.2 E-4

285 T a b . 5 - 5 , continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν * I

1247

(2)

36 a

Eu-150

Eu-151

2.8 E-6

1250

(0.4)

3.1 h

Er-161

Er-162

8.4 E-4

1251

(0.09)

72.1 d

Tb-160

Tb-159,

1251

(0.9)

9.59 h

Dy-155

Dy-156

1253

(0.3)

14.4 m

In-112

In-113

1257

(0.08)

17.6 m

Br-80

Br-81,

1257

(0.8)

2.7 d

Sb-122

S b - 1 2 3 , Te-123

2 . 1 E-2

1257

(2)

115 d

Ta-182

W-183, T a - 1 8 1

4 . 8 E-5

1259

(4)

4.4 m

In-118m

Sn-119

1.8 E-4

1260

(1)

14.6 h

Ga-72

Ge-73, Ga-71

1.3 E-3

1261

(0.01)

69.6 m

Te-129

Te-130

1.9 E-3

Dy-161

3.9 E-6 1.4 E-4 1.5 E-2

Rb-85

5 . 5 E+l

1261

(0.9)

68.3 m

Ga-68

Ga-69, Ge-70

8.1 E - l

1262

(0.3)

1.65 h

Ru-95

Ru-96

5 . 1 E-2

1263

(4)

48.4 m

Au-200

Hg-201

1268

(?)

2.246 m

Al-28

S i - 2 9 , P - 3 1 , Al-27

1.3 E-3 ?

1268

(0.2)

3.1 h

Er-161

Er-162

4 . 2 E-4

1269

(0.2)

74 m

Nb-97

Mo-9 8

3.8 E-3

1270

(1)

14.6 h

Nb-90

Mo-92

3.8 E-4

1271

(4)

5.7 h

Mo-90

Mo-9 2

6 . 0 E-4

1272

(8)

72.1 d

Tb-160

T b - 1 5 9 , Dy-161

1272

(3)

5 h

Ho-160m

Er-161

3.4 E-4 ?

1273

(0.09)

33 h

Sr-83

Sr-84

2.5 E - 5

1273

(14)

7.7 h

Tm-166

Tm-169

4.9 E-4

1274

(91)

6.6 m

Al-29

Si-30

1.4

1274

(0.7)

115 d

Ta-182

W-183, T a - 1 8 1

1.7 E - 5

1275

(0.8)

55 m

Cd-105

Cd-106

4.4 E-4

1275

(100)

2.62 a

Na-22

Na-23, Mg-24, Al-27

3.0 E-3

1275

(35)

8.5 a

Eu-154

Eu-153, Gd-155

6.7 E-5

1275

(0.1)

38 d

Re-184

Re-185

2.0 E-4

1277

(1)

14.1 h

Ga-72

Ge-73, Ga-71

1.3 E-3

1277

(2)

93.1 d

Tm-168

Tm-169

3.4 E-3

1278

(3)

15.2 d

Eu-156

Gd-157

2.8 E-5

1280

(0.6)

3.1 h

Er-161

Er-162

1.3 E-3

1285

(0.07)

33 h

Sr-83

Sr-84

2.0 E-5

1286

(2)

(5 h)

Ho-160m

Er-160

?

1286

(0.02)

72.1 d

Tb-160

T b - 1 5 9 , Gd-161

2.2 E-7

1289

(11)

1.6 m

V-53

Cr-54

4 . 0 E-2

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

1289

(2)

8.47 h

1289

(0.2)

6.7 d

Pd-101

Pd-102

1.6

Lu-172

Lu-175

1289

2.0 E - 5

(1)

115 d

Ta-182

W-183, T a - 1 8 1

2.4 E-5

1290

(0.8)

44.8 d

Cd-115m

Cd-116

2.0 E-6

1290

(0.4)

3.85 d

Sb-127

Te-128

6.0 E-5

1292

(44)

44.6 d

Fe-59

F e - 5 8 , Ni-64

9

1293

(?)

35.3 m

Sn-111

Sn-112

?

1293

(0.4)

2.5 h

Nd-141

Nd-142

6.4 E-2

1294

(85)

54 m

In-116ml

In-115, Sn-117

7.8

1294

(99)

1.83 h

Ar-41

K-41

w

1295

(0.2)

9.59 h

Dy-155

Dy-156

3 . 0 E-5

1297

(0.2)

33 h

Sr-83

Sr-84

5 . 5 E-5

1297

(75)

4.54 d

Ca-47

Ca-48

2.8 E-3

Mo-92

9

1297

(?)

14.6 h

Nb-90

1298

(0.06)

6.47 d

Cs-132

Cs-133

1.4 E-3

1299

(0.1)

2.5 h

Nd-141

Nd-142

1.6 E-2

1299

(2)

12.4 a

Eu-152

Eu-153

1.7 E-5

1299

(0.07)

17 h

Ce-135

Ce-136

1300

(?)

2.58 h

Mn-56

Mn-55, Fe-57

2.6 E-5 ?

1300

(0.1)

71.9 s

In-114

In-115, Sn-115

7.6

1301

(0.3)

18.7 m

Eu-159

Gd-160

1.2 E-3

1302

(0.2)

39 m

Se-73m

Se-74

6.4 E-3

1302

(4)

55 m

Cd-105

Cd-106

2.2 E-3

1303

(0.4)

3.1 h

Er-161

Er-162

8.3 E-4

1304

(0.2)

9.59 h

Dy-155

Dy-156

3.1 E - 5

1308

(0.07)

16.98 h

Re-188

Re-187, Os-189

4 . 1 E-4

1309

(13)

1.5 h

As-78

Se-80

2.9 E-3

1309

(0.9)

36 a

Eu-150

Eu-151

1.2 E-6

1312

(0.2)

8.47 h

Pd-101

Pd-102

1.7 E - l

1312

(100)

43.67 h

Sc-48

Ti-49

3.1 E-2

1312

(99)

15.97 d

V-48

C r - 5 0 , V-50

3 . 1 E-4

1312

(1)

3.12 h

Ag-112

C d - 1 1 3 1 . 6 E-4

1312

(3)

72.1 d

Tb-160

T b - 1 5 9 , Dy-161

1.3 E-4

1315

(0.8)

9.3 h

Eu-152m2

Eu-153

6 . 0 E-3

1316

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E-5

1317

(29)

35.34 h

Br-82

Br-81, Sr-87

1.4 E-3

1318

(0.6)

6.47 d

Cs-132

Cs-133

1.4 E-2

287 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I 2 . 1 E-4

1318

(0.1)

3.1 h

Er-161

Er-162

1318

(0.08)

3.31 h

Lu-174

Lu-175

5 . 1 E-6

1320

(2)

68 m

Ho-162m

Ho-165

7 . 2 E-3

1321

(0.2)

55 m

Cd-105

Cd-106

1 . 1 E-4

1324

(0.5)

12.1 d

Ir-190

Ir-191

3.6 E-3

1325

(0.3)

33 h

Sr-83

Sr-84

1325

(?)

107 d

Y-88

Y-89,

1326

(0.3)

20 h

Rh-100

Pd-102

7 . 8 E-5

1328

(87)

2.5 m

Fe-53m

F e - 5 4 , Ni-58

1.4 E-4

1333

(100)

5.272 a

Co-60

Ni-61, Co-59, Cu-65

1.4 E-4

1333

(5)

5.7 d

Mn-52

Fe-54

8 . 5 E-6

1336

(3)

39 h

Ge-69

Ge-70, S e - 7 4

3.6 E-2

1337

(0.4)

9.59 h

Dy-155

Dy-156

6.0 E-5

1338

(0.2)

3.1 h

Er-161

Er-162

4 . 2 E-4

1339

(0.7)

1.5 h

As-78

Se-80

1.6 E-4

1339

(0.7)

55 m

Cd-105

Cd-106

3.9 E-4

1339

(0.2)

16 h

Te-119

Te-120

1.0 E - 5

1340

(0.3)

1.65 h

Ru-95

Ru-96

5.2 E-2

1341

(1)

9.25 m

Ta-178

Ta-180, , VV-180

4.4 E-2

1341

(5)

28.4 m

Lu-178

Hf-179

w

1342

(7)

69.2 h

Ag-104

Cd-106

3.7 E-5

1342

(57)

21.2 h

Mg-28

Si-30

9

1342

(5)

20

Rh-100

Pd-102

1.3 E-3

1342

(1)

39.5 h

Au-194

Au-197

7.6 E-4

1343

(0.02)

8.47 h

Pd-101

Pd-102

1.7 E-2

1343

(0.3)

115 d

Ta-182

W-183, T a - 1 8 1

7 . 2 E-6

1344

(3)

36 a

Eu-150

Eu-151

4 . 2 E-6

1345

(3)

54 d

Eu-148

Eu-151

1.3 E - 5

1346

(0.5)

12.7 h

Cu-64

C u - 6 5 , Zn-66, Ga-69

3.7 E-2

1347

(90)

115 s

K-46

Ca-48

·>

1347

(0.4)

4.54 h

Pr-139

Pr-141

4.0 E - l

1349

(0.2)

39 h

Ge-69

Ge-70, S e - 7 4

2.4 E-3 4.4 E-2 4 . 1 E-4

h

8.4 E - 5 Zr-90

?

1351

(1)

9.25 m

Ta-178

Ta-180, , VV-180

1351

(0.1)

18.7 m

Eu-159

Gd-160

1354

(3)

3.93 h

La-141

Ce-142

1.1 E-5

Os-184

2.0 E-5

Ru-96

1.9 E - l

1354

(0.2)

10 h

Os-183m

1355

(1.1)

1.65 h

Ru-95

T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

1357

(0.5)

3.12 h

Ag-112

Cd-113

8 . 0 E-5

1358

(0.6)

3.1 h

Er-161

Er-162

1.3 E-3

1360

(4)

77.3 d

Co-5 6

Ni-58

5.2 E-5

1361

(0.7)

55 m

Cd-105

Cd-106

3.9 E-4

1362

(16)

20 h

Rh-100

Pd-102

4 . 2 E-3

1362

(0.4)

206 d

Rh-102

Rh-103,, Pd-104

1.9 E-4

1366

(0.9)

4.7 d

Te-119m

Te-120

3.5 E-6

1367

(2)

15.2 d

Eu-156

Gd-157

1.8 E-5 7.2 E-6

1368

(2)

60.3 d

Sb-124

T e - 1 2 5 , Sb-123

1368

(0.7)

9.59 h

Dy-155

Dy-156

1.1 E - 4

1369

(100)

15 h

Na-24

Mg-25, Na-23, Al-27

2.5 E - l

1373

(0.5)

68 m

Ho-162m

Ho-165

1.8 E-3

1373

(4)

1.5 h

As-78

Se-80

8 . 6 E-4

1374

(0.2)

115 d

Ta-182

VV-183, T a - 1 8 1

4.8 E-6

1375

(0.07)

33 h

Sr-83

Sr-84

2.0 E - 5

1376

(0.1)

4.5 h

Pr-139

Pr-141

1.0 E - l

1378

(79)

36 h

Ni-57

Ni-58

7.9 E - l

1378

(0.07)

3.85 d

Sb-127

Te-128

1.0 E - 5

1379

(0.9)

26.7 h

Ho-166

Ho-165, Er-167

4.0 E-3

1382

(1)

1.5 h

As-78

Se-80

2.2 E - 4

1383

(0.1)

3.1 h

Er-161

Er-162

2.1 E-4

(90)

2.71 h

Sr-92

Zr-96

6.3 E-3

1384

(25)

250 d

Ag-110m

Ag-109,, Cd-111

1.1 E - 5

1385

(0.1)

33 h

Sr-83

Sr-84

2.8 E-5

1387

(0.1)

38 d

Re-184

Re-185

2 . 0 E-4

1387

(2)

5.7 h

Mo-90

Mo-92

3.0 E-4

1387

(0.4)

20 h

Rh-100

Pd-102

1.0 E - 4

1387

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E-5

1387

(5)

63.6 h

Tm-172

Yb-173

2.8 E - 4

1387

(0.8)

6.7 d

Lu-172

Lu-175

7.7 E - 5

1387

(0.08)

115 d

Ta-182

VV-183, T a - 1 8 1

2.1 E-6

1387

(0.2)

12.1 d

Ir-190

Ir-191

1.4 E - 3

1388

(5)

3.12 h

Ag-112

Cd-113

8.0 E-4

1388

(3)

55 m

Cd-105

Cd-106

1.6 E-3

1389

(0.7)

9.3 h

Eu-152m2

Eu-153

5.3 E - 3

1394

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E-5

1394

(1)

8.3 d

Ag-106m

Ag-107

4.2 E - 4

1384

289 T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

1403

CO.5)

9.25 m

Ta-178

T a - 1 8 0 , W-180

2.2 E-2

1403

(0.4)

55 m

Cd-105

Cd-106

2.2 E-4

1403

(0.6)

6.7 d

Lu-172

Lu-175

5.9 E-5

1403

(0.3)

8.83 m

Sm-143

Sm-144

5.7 E-2

1404

(?)

6.6 m

Al-2 9

Si-30

·>

1405

(0.01)

39 h

Ge-69

Ge-70, S e - 7 4

1.2 E-4

1405

(5)

3.51 h

Y-92

Zr-94

5.0 E-4

1405

(1)

6.24 d

Bi-206

Bi-209

2.9 E-5

1408

(0.1)

3.08 h

Ti-45

Ti-46

2.9 E-3

1408

(21)

12.4 a

Eu-152

Eu-153

1409

(?)

36 h

Ni-57

Ni-58

1.7 E-4 9

1410

(0.04)

115 d

Ta-182

W-183, Ta-181

9.6 E-7

1411

(2)

1.65 h

Ru-95

Ru-96

3.4 E - l

1412

(1)

38.4 m

Zn-63

Zn-64

1.0

1413

(1)

16 h

Te-119

Te-120

5.1 E - 5

1415

(0.3)

9.59 h

Dy-155

Dy-156

4 . 5 E-5

1416

(2)

55 m

Cd-105

Cd-106

1.1 E-3

1418

(0.6)

3.1 h

Er-161

Er-162

1.2 E-3

1419

(?)

20 h

Rh-100

Pd-102

·>

1420

(0.3)

13 d

1-126

1-127

3.3 E-3

1422

(12)

5.35 d

Tb-156

Tb-159

1.4 E-4

1427

(0.4)

9.59 h

Dy-155

Dy-156

6 . 0 E-5

1427

(9)

64 h

Re-182

Re-185, Os-184

1.8 E-4

1429

(0.4)

3.1 h

Er-161

Er-162

8 . 5 E-4

1433

(0.6)

1.65 h

Ru-95

Ru-96

1.0 E - l

1433

(0.03)

8.47 h

Pd-101

Pd-102

2 . 5 E-2

1434

(100)

3.75 m

V-52

C r - 5 3 , V-51

2.3

Ν ' I

1434

(100)

5.7 d

Mn-52

Fe-54

1434

(98)

21 m

Mn-52m

Fe-54

1.7 E-4 9

1434

(0.2)

18.7 m

Eu-159

Gd-160

8 . 0 E-4

1435

(0.02)

2.5 h

Nd-141

Nd-142

3 . 2 E-3

1435

(0.2)

3.1 h

Er-161

Er-162

4 . 2 E-4

1438

(0.3)

9.59 h

Dy-155

Dy-156

4 . 5 E-5

1439

(0.3)

26.4 h

As-76

As-75, Se-77

3.9 E-4

1440

(0.05)

17 h

Ce-135

Ce-136

1.8 E-5

1440

(0.7)

6.7 d

Lu-172

Lu-175

6 . 8 E-5

1440

(0.6)

14 h

Os-183

Os-184

1.6 E - 5

290

T a b . 5-5, continued

E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

1441

(0.4)

23.4 h

Nb-96

Mo-9 7

3.1 E-4

1442

(0.1)

38 a

Bi-207

Bi-209

2.7 E-7

1443

(0.2)

77.3 d

Co-56

Ni-58

2.6 E-6

1450

(0.03)

39 h

Ge-69

Ge-70, S e - 7 4

3.6 E - 4

1452

(0.01)

12.6 h

Eu-150m

Eu-151

5.9 E-4 9 . 6 E-7

1453

(0.04)

115 d

Ta-182

W-183, T a - 1 8 1

1454

(0.1)

26.4 h

As-76

As-75, Se-77

1.3 E - 4

1455

(2)

5.7 h

Mo-90

Mo-9 2

3.0 E-4

1459

(2)

1.65 h

Ru-95

Eu-96

3.4 E - l

1459

(56)

2.13 h

Ba-129m

Ba-130

1.2 E-2

1462

(0.08)

77.3 d

Co-56

Ni-58

1.0 E-6

1462

(0.3)

93.1 d

Tm-168

Tm-169

5.1 E-4

1464

(4)

14.1 h

Ga-72

Ge-73, Ga-71

5.2 E - 3

1464

(1)

26 h

As-72

Se-74

1.0 E-5

1464

(0.2)

3.1 h

Er-161

Er-162

4.2 E - 4

1465

(22)

5.37 d

Pm-148

Sm-149

4.8 E-4

1466

(4)

63.6 h

Tm-172

Yb-173

2.2 E-4

1466

(0.7)

6.7 d

Lu-172

Lu-175

6 . 8 E-5

1467

(0.2)

17 h

Ce-135

Ce-136

7 . 4 E-5

1469

(0.6)

3.12 h

Ag-112

Cd-113

9 . 6 E-5

1469

(6)

39.5 h

Au-194

Au-197

4.6 E-3

1469

(0.2)

19.4 h

Ir-194

Ir-193, Pt-195

1.9 E-4

1470

(0.01)

39 h

Ge-69

Ge-70, S e - 7 4

1.2 E - 4

1470

(0.6)

6.7 d

Lu-172

Lu-175

5.8 E - 5

1475

(17)

35.34 h

Br-82

Br-81, Sr-87

8.3 E-4

1476

(0.5)

26 h

As-72

Se-74

5.0 E-6

1477

(99)

6.9 h

Mo-9 3m

Mo-94

3.2 E - l

1477

(0.2)

11 h

Pt-189

Pt-190

2.0 E-4

1479

(0.5)

9.59 h

Dy-155

Dy-156

7.2 E-5

1481

(27)

2.52 h

Ni-65

Ni-64, Z n - 7 0

1.6 E-2

1485

(2)

37 a

Eu-150

Eu-151

2 . 8 E-6

1486

(?)

14.1 h

Ga-72

G e - 7 3 , Ga-71

?

1487

(0.06)

39 h

Ge-69

Ge-70, S e - 7 4

7.2 E-4

1488

(0.6)

55 m

Cd-105

Cd-106

3 . 3 E-4

1489

(0.3)

17.3 m

Pr-144

Nd-145

3.9 E-4

1489

(1)

6.7 d

Lu-172

Lu-175

1.0 E-4

1492

(0.3)

3.1 h

Er-161

Er-162

6 . 3 E-4

291 T a b . 5 - 5 , continued E.keV (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I 7 . 5 E-5

1493

(0.5)

9.59 h

Dy-155

Dy-156

1496

(0.3)

9.25 m

Ta-178

T a - 1 8 0 , W-180

1.3 E-2

1498

(3)

23.4 h

Nb-96

Mo-9 7

2 . 3 E-3

1500

(1)

3.92 h

Sc-44

C s - 4 5 , Ti-46

2.5 E - l

1501

(0.06)

17 h

Ce-135

Ce-136

2.3 E - 5

1504

(0.9)

4.4 m

In-118m

Sn-119

4.1 E-5

1505

(13)

250 d

Ag-110m

Ag-109,, Cd-111

5 . 3 E-6

1507

(10)

54 m

In-116ml

In-115, Sn-117

9.1 E-l

1508

(6)

4.16 m

Zr-89m

Zr-90

1.2 E + l

1508

(25)

65 s

Mo-91m

Mo-92

3.5

1509

(0.3)

9.59 h

Dy-155

Dy-156

4 . 5 E-5

1515

(0.02)

8.47 h

Pd-101

Pd-102

1.7 E-2

1515

(0.7)

8.83 m

Sm-143

Sm-144

1.3 E - l

1516

(0.1)

74 m

Nb-97

Mo-9 8

1.9 E-3

1520

(0.7)

18.7 m

Eu-159

Gd-160

2.9 E-3

1522

(5)

53 m

Tc-94m

Ru-96

3.7 E-4

1525

(18)

12.36 h

K-42

Ca-43, K-41

1.0 E-3

1526

(0.1)

39 h

Ge-69

Ge-70, S e - 7 4

1.2 E-3

1527

(18)

2.2 h

Rh-106m

Pd-108

1.2 E - l

1528

(0.1)

33 h

Sr-83

Sr-84

2.8 E-5

1528

(16)

8.3 d

Ag-106m

Ag-107

6.7 E-3

Se-80

6 . 6 E-4

1530

(3)

1.5 h

As-78

1530

(5)

63.6 m

Tm-172

Yb-173

2.8 E-4

1531

(0.02)

17 h

Ce-135

Ce-136

7 . 5 E-6

1539

(0.5)

3.12 h

Ag-112

Cd-113

8 . 0 E-5

1542

(0.2)

1.65 h

Ru-95

Ru-96

3.4 E-2

1543

(0.4)

35.3 m

Sn-111

Sn-112

5.6 E-3

1543

(1)

6.7 d

Lu-172

Lu-175

1.0 E-4

1544

(0.05)

8.83 m

Sm-143

Sm-144

9 . 3 E-3

1547

(0.1)

38.4 m

Zn-63

Zn-64

1.0 E - l

1553

(22)

20 h

Rh-100

Pd-102

5.8 E-3

1554

(100)

1.7 m

Sc-50

Ti-50

w

1554

(0.1)

3.1 h

Er-161

Er-162

2 . 1 E-4

1558

(2)

55 m

Cd-105

Cd-106

1.1 E-3

1560

(1)

20 h

Rh-100

Pd-102

2.5 E-4

1560

(0.07)

17 h

Ce-135

Ce-136

2.6 E-5

1562

(0.2)

1.65 h

Ru-95

Ru-96

3 . 5 E-2

292 T a b . 5-5, continued Nuclide

T a r g e t Nuclide

Ν * I

Rh-102

Rh-103,, Pd-104

4 . 7 E-5

Ag-106

Ag-107, , Cd-108

2.2 E - l

Ni-58

2.7 E-4

Sr-83

Sr-84

5.6 E-4

Au-194

Au-197

2.3 E - 4

Ag-107

2.3 E-3

E,keV (1%)

Τ

1562

C0.1)

206 d

1562

(0.02)

24 m

1562

(13)

6.1 d

Ni-56

1562

(2)

33 h

1563

(0.3)

39.5 h

1565

(6)

8.3 d

Ag-106m

1572

(0.8)

14.1 h

Ga-72

Ge-73, Ga-71

1.0 E-3

1572

(7)

8.3 d

Ag-106m

Ag-107

3 . 0 E-3

1573

(0.2)

39 h

Ge-69

Ge-70, S e - 7 4

2 . 5 E-3

1574

(0.09)

9.59 h

Dy-155

Dy-156

1.4 E - 5

1576

(4)

19.2 h

Pr-142

P r - 1 4 1 , Nd-143

1576

(3)

40.5 s

Pm-142

Sm-144

1.9 E-3 9

1577

(?)

77.3 d

Co-56

Ni-58

·>

Rh-103,, Pd-104

2.4 E-5

1581

(0.05)

206 d

Rh-102

1582

(0.2)

15.5 m

Mo-91

Mo-92

5.4 E-4

1582

(0.2)

26.7 h

Ho-166

Ho-165, Er-167

8.8 E-4

1583

(1)

55 m

Cd-105

Cd-106

5 . 5 E-4

1584

(3)

6.7 d

Lu-172

Lu-175

2.9 E-4

1592

(2)

4.9 h

Tc-94

Ru-96

1.0 E-3

1594

(3)

39.5 h

Au-194

Au-197

2.3 E-3

1595

(5)

6.24 d

Bi-206

Bi-209

1.4 E-4

1596

(96)

40.2 h

La-140

La-139

1.2 E-2

1596

(0.5)

3.4 m

Pr-140

Pr-141

9.5 E - l

1597

(4)

14.1 h

Ga-72

Ge-73, Ga-71

5.2 E-3

1598

(0.03)

33 h

Sr-83

Sr-84

8 . 4 E-6

1599

(0.2)

9.59 h

Dy-155

Dy-156

3.0 E - 5

1601

(?)

54 m

In-116ml

In-115, Sn-117

?

1603

(0.3)

6.7 d

Lu-172

Lu-175

2.9 E-5

1608

(0.03)

8.47 h

Pd-101

Pd-102

2.6 E-2

1608

(0.02)

2.5 h

Nd-141

Nd-142

3.2 E-3

1608

(4)

63.6 h

Tm-172

Yb-173

2.3 E-4

1610

(0.7)

35.3 m

Sn-111

Sn-112

9 . 5 E-3

1610

(0.1)

16.98 h

Re-188

Re-187, Os-189

5.9 E-4

1612

(10)

59.6 s

Na-25

Mg-26

3.6 E - l

1612

(2)

14.6 h

Nb-90

Mo-92

7.6 E-4

1614

(3)

3.12 h

Ag-112

Cd-113

1615

(0.01)

39 h

Ge-69

Ge-70, S e - 7 4

4 . 8 E-4 7

293 T a b . 5 - 5 , continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

1618

(?)

32 m

Cl-34m

Cl-35

·>

1621

(0.07)

78.4 h

Zr-89

Zr-90

1.1 E-3

1622

(5)

54 d

Eu-148

Eu-151

2.2 E - 5

1622

(2)

6.7 d

Lu-172

Lu-175

2 . 0 E-4

1624

(11)

2.13 h

Ba-129m

Ba-130

2.3 E-3

1626

(0.1)

23.4 h

Nb-96

Mo-9 7

7.7 E - 5

1628

(2)

20 h

Rh-100

Pd-102

5.2 E-4

1629

(0.06)

12.6 h

Eu-150m

Eu-151

3.6 E-3

1631

(0.3)

4.5 h

Pr-139

Pr-141

3.0 E - l

1633

(0.02)

8.47 h

Pd-101

Pd-102

1.7 E-2

1636

(1)

55 m

Cd-105

Cd-106

5.4 E-4

1636

(0.7)

35 a

Eu-150

Eu-151

9 . 8 E-7

1637

(0.3)

15.5 m

Mo-91

Mo-92

8 . 3 E-4

1642

(33)

37.18 m

Cl-38

Cl-37

3 . 1 E-2

1644

(0.9)

55 m

Cd-105

Cd-106

5.0 E-4

1650

(4)

54 d

Eu-148

Eu-151

1.6 E - 5

1653

(0.1)

33 h

Sr-83

Sr-84

1656

(?)

7.7 m

K-38

K-39,

1657

(0.1)

78.4 h

Zr-89

Zr-90

1.6 E-3

1657

(0.6)

3.1 h

Er-161

Er-162

1.2 E-3

1665

(3)

55 m

Cd-105

Cd-106

1.7 E-3

1665

(0.9)

9.59 h

Dy-155

Dy-156

1.3 E-4

1666

(0.09)

33 h

Sr-83

Sr-84

2.5 E-5

1670

(0.6)

6.7 d

Lu-172

Lu-175

5.9 E-5

1675

(0.5)

70.78 d

Co-58

Co-59, Ni-60, Cu-63

7 . 0 E-4

1675

(?)

14.6 h

Nb-90

Mo-92

·>

1681

(1)

14.1 h

Ga-72

Ge-73, Ga-71

1.3 E-3 1 . 5 E-5

Ca-40

2.8 E - 5 ?

1685

(0.1)

9.59 h

Dy-155

Dy-156

1691

(?)

14.1 h

Ga-72

Ge-73, Ga-71

1691

(49)

60.3 d

Sb-124

T e - 1 2 5 , Sb-123

1.8 E-4

1693

(4)

55 m

Cd-105

Cd-106

2.2 E-3

1701

(0.2)

20 h

Rh-100

Pd-102

5 . 2 E-5

1709

(0.2)

20 h

Rh-100

Pd-102

5.2 E-5

1711

(0.04)

33 h

Sr-83

Sr-84

1 . 1 E-5

1711

(0.4)

14.1 h

Ga-72

Ge-73, Ga-71

5 . 2 E-4

1713

(0.8)

78.4 h

Zr-89

Zr-90

1.3 E-2

1715

(0.7)

39.5 h

Au-194

Au-197

5.3 E-4

294

T a b . 5-5, continued

Ε, keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I 2.0 E-4

1716

(0.5)

14.6 h

Nb-90

Mo-92

1716

(6)

41.5 h

Ir-188

Ir-191, Pt-190

4.6 E-5

1719

(32)

6.24 d

Bi-206

Bi-209

9.3 E-4

1722

(0.6)

1.5 h

As-78

Se-80

1.3 E-4

1723

(1)

8.3 d

Ag-106m

Ag-107

4.2 E-4

1724

(0.04)

39 h

Ge-69

Ge-70, Se-74

4.8 E-4

1724

(0.4)

6.7 d

Lu-172

Lu-175

3.9 E-5

1725

(0.7)

55 m

Cd-105

Cd-106

3.9 E-4

Mg-25, Na-23, Al-27

9

1732

(?)

15 h

Na-24

1740

(0.4)

3.1 h

Er-161

Er-162

8.4 E-4

1745

(0.1)

78.4 h

Zr-89

Zr-90

1.6 E-3

1750

(4)

16

Te-119

Te-120

2.0 E-4

1752

(2)

54 m

In-116ml

In-115, Sn-117

1.8 E - l

1753

(0.009) 2.7 d

Sb-122

Sb-123,, Te-123

2.3 E-4

h

1757

(0.03)

33 h

Sr-83

Sr-84

8.4 E-6

1758

(7)

36 h

Ni-57

Ni-58

7.0 E-2

1761

(0.003) 64.1 h

Y-90

Zr-91, Y-89

1.0 E-4

1762

(0.1)

57.2 m

Sc-49

Ti-50

9.3 E-5

1770

(7)

38 a

Bi-207

Bi-209

9

1771

(16)

77.3 d

Co-56

Ni-58

2.0 E-4

1778

(0.03)

33 h

Sr-83

Sr-84

8.4 E-6

1779

(100)

2.246 m

Al-28

Si-29, :P-31, Al-27

3.6

1785

(0.6)

1.65 h

Ru-95

Ru-96

1.0 E - l

1786

(0.01)

206 d

Rh-102

Rh-103,, Pd-104

4.7 E-6

1788

(0.3)

26.4 h

As-76

As-75, Se-77

3.9 E-4

1792

(1)

1.5 h

As-78

Se-80

2.2 E-4

1794

(0.04)

8.3 d

Ag-106m

Ag-107

1.7 E-5 1.1 E - l

1796

(0.01)

24 m

Ag-106

Ag-107,, Cd-108

1798

(1)

3.12 h

Ag-112

Cd-113

1.6 E-4

1798

(0.6)

39.5 h

Au-194

Au-197

4.6 E-4

1799

(0.05)

33 h

Sr-83

Sr-84

1.4 E-5

1808

(?)

14.6 h

Nb-90

Mo-92

9

1810

(0.6)

77.3 d

Co-56

Ni-58

7.8 E-6

1811

(29)

2.58 h

Mn-56

Mn-55, Fe-57

1.1 E - l

1813

(0.2)

6.7 d

Lu-172

Lu-175

1.9 E-5

1817

(0.03)

8.83 m

Sm-143

Sm-144

5.7 E-3

1823

(0.2)

55 m

Cd-105

Cd-106

1.1 E-4

295

T a b . 5-5, continued E.keV (1%)

Τ

Nuclide

Target Nuclide

Ν ' I

1830

(4)

2.13 h

Ba-129m

Ba-130

8.4 E-4

1832

(0.2)

55 m

Cd-105

Cd-106

1.1 E-4

1836

(21)

17.8 m

Rb-88

Rb-87

2.1 E-2

1836

(99)

108 d

Y-88

Y-89,

1836

(2)

1.5 h

As-78

Se-80

4.4 E-4

1839

(2)

8.3 d

Ag-106m

Ag-107

8.4 E-4

Zr-90

1.1 E - l

1842

(3)

20 m

Ag-115

Cd-116

5.0 E-3

1843

(0.7)

14.6 h

Nb-90

Mo-92

2.7 E-4

1844

(0.6)

6.24 d

Bi-206

Bi-209

1.8 E-5

1847

(0.8)

10.15 d

Nb-92m

Nb-93, Mo-94

4.3 E-3

1861

(5)

14.1 h

Ga-72

Ge-73, Ga-71

6.5 E-3

1865

(?)

20 h

Rh-100

Pd-102

9

1869

(6)

53 m

Tc-94m

Ru-96

4.5 E-4

1870

(0.6)

55 m

Cd-105

Cd-106

3.3 E-4

1874

(0.04)

33 h

Sr-83

Sr-84

1.1 E-5

1879

(2)

6.24 d

Bi-206

Bi-209

5.8 E-5

1884

(0.2)

68.3 m

Ga-68

Ga-69, Ge-70

1.7 E - l

1886

(3)

39.5 h

Au-194

Au-197

2.2 E-3

1891

(0.2)

39 h

Ge-69

Ge-70, Se-74

2.4 E-3

1895

(0.4)

1.5 h

As-78

Se-80

8.9 E-5

1897

(0.8)

34.5 d

Rb-84

Rb-85, Sr-86

2.1 E-3

1898

(2)

55 m

Cd-105

Cd-106

1.1 E-3

1903

(0.3)

6.24 d

Bi-206

Bi-209

8.7 E-6

1910

(0.6)

55 m

Cd-105

Cd-106

3.3 E-4

1912

(0.05)

33 h

Sr-83

Sr-84

1.4 E-5

1913

(1)

14.6 h

Nb-90

Mo-92

3.8 E-4

1914

(2)

10.1 h

Y-93

Zr-94

2.2 E-3

1915

(1)

35.3 m

Sn-111

Sn-112

1.4 E-2

1915

(?)

6.6 m

Al-29

Si-30

9

1915

(0.6)

6.7 d

Lu-172

Lu-175

5.8 E-5

1920

(15)

36 h

Ni-57

Ni-58

1.5 E - l

1922

(2)

1.5 h

As-78

Se-80

4.5 E-4

1923

(0.08)

39 h

Ge-69

Ge-70, Se-74

9.6 E-4

1924

(2)

39.5 h

Au-194

Au-197

1.5 E-3

1930

(10)

20

Rh-100

Pd-102

2.6 E-3

1931

(0.3)

1.65 h

Ru-95

Ru-96

5.1 E-2

1931

(0.4)

6.7 d

Lu-172

Lu-175

3.9 E-5

h

296 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

1933

(2)

55 m

Cd-105

Cd-106

1.1 E-3

1944

(4)

41.5 h

Ir-188

I r - 1 9 1 , Pt-190

3.1 E-5

1952

(1)

33 h

Sr-83

Sr-84

2.8 E-4

1961

(0.9)

55 m

Cd-105

Cd-106

5.0 E-4

1963

(0.1)

12.6 h

Eu-150m

Eu-151

5.9 E-3

1964

(0.7)

77.3 d

Co-56

Ni-58

9 . 1 E-6

1966

(4)

15.2 d

Eu-156

Gd-157

3.8 E-5

1976

(0.3)

55 m

Cd-105

Cd-106

1.7 E-4

1977

(0.4)

20 h

Rh-100

Pd-102

1.0 E-4

1984

(0.6)

14.6 h

Nb-90

Mo-92

2.4 E-4

1985

(0.07)

6.47 d

Cs-132

Cs-133

1.7 E-3

1987

(0.8)

55 m

Cd-105

Cd-106

4.4 E - 4

1988

(0.7)

1.65 h

Ru-95

Ru-96

1.2 E - l

1994

(0.2)

6.7 d

Lu-172

Lu-175

1997

(?)

14.1 h

Ga-72

Ge-73, Ga-71

1.9 E-5 ?

1997

(1)

1.5 h

As-78

Se-80

2.2 E-4

2013

(100)

17.5 s

K-47

Ca-48

4.2 E-2

2015

(3)

77.3 d

Co-56

Ni-58

3.9 E-5

2015

(0.05)

33 h

Sr-83

Sr-84

1.4 E-5

2022

(0.3)

39 h

Ge-69

Ge-70, S e - 7 4

3.6 E-3

2024

(0.5)

6.7 d

Lu-172

Lu-175

4 . 8 E-5

2028

(3)

6.6 m

Al-29

Si-30

4 . 5 E-2

2028

(0.6)

55 m

Cd-105

Cd-106

3.3 E-4

2035

(8)

77.3 d

Co-56

Ni-58

1.0 E-4

2037

(0.03)

206 d

Rh-102

Rh-103,, Pd-104

1.4 E - 5

2043

(0.01)

39 h

Ge-69

Ge-70, S e - 7 4

1.2 E-4

2044

(4)

39.5 h

Au-194

Au-197

3.1 E-3

2047

(0.3)

1.65 h

Ru-95

Ru-96

5 . 1 E-2

2048

(0.1)

33 h

Sr-83

Sr-84

2.0 E-5

(20)

7.7 h

Tm-166

Tm-169

7 . 1 E-4

2054

(0.6)

55 m

Cd-105

Cd-106

3.3 E-4

2057

(0.6)

3.12 h

Ag-112

Cd-113

9.6 E-5

2060

(7)

41.5 h

Ir-188

I r - 1 9 1 , Pt-190

5.3 E - 5

2069

(0.8)

1.5 h

As-78

Se-80

1.7 E-4

2083

(0.3)

6.7 d

Lu-172

Lu-175

2.9 E - 5

2084

(0.02)

8.3 d

Ag-106m

Ag-107

2088

(?)

77.3 d

Co-56

Ni-58

8.7 E-6 ?

2053

297 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I

2090

(5)

4.7 d

Te-119m

Te-120

2.0 E-5

2090

(0.2)

33 h

Sr-83

Sr-84

5.6 E-5

2091

(6)

60.3 d

Sb-124

Te-125, , Sb-123

2.2 E - 5

2095

(0.3)

1.5 h

As-78

Se-80

6.6 E - 5

2096

(0.1)

6.7 d

Lu-172

Lu-175

1.0 E - 5

2096

(0.05)

26.4 h

As-76

A s - 7 5 , Se-77

6.5 E-5

2098

(11)

41.5 h

Ir-188

I r - 1 9 1 , Pt-190

8.5 E-5

2106

(0.7)

26 h

As-72

Se-74

7 . 0 E-6

2106

(2)

3.12 h

Ag-112

Cd-113

3 . 2 E-4

2110

(1)

14.1 h

Ga-72

Ge-73, Ga-71

1.2 E-2

2111

(0.3)

26.4 h

As-76

A s - 7 5 , Se-77

3.9 E-4

2112

(15)

54 m

In-116ml

In-115, Sn-117

1.5

2113

(16)

2.58 h

Mn-56

Mn-55, Fe-57

5.9 E-2

2114

(0.4)

77.3 d

Co-56

Ni-58

5.2 E-6

2117

(0.09)

55 m

Cd-105

Cd-106

5.0 E - 5

2129

(38)

32 m

Cl-34m

Cl-35, K-39

3.5

2133

(0.04)

36 h

Ni-57

Ni-58

4 . 0 E-4

2135

(0.03)

33 h

Sr-83

Sr-84

8 . 4 E-6

2148

(0.2)

33 h

Sr-83

Sr-84

5.6 E - 5

2156

(0.4)

55 m

Cd-105

Cd-106

2168

(100)

7.7 m

K-38

K-39,

2168

(44)

37.18 m

Cl-38

Cl-37

4 . 1 E-2

2175

(8)

10.3 m

Y-95

Zr-96

3.4 E - l

2179

(0.1)

35.3 m

Sn-111

Sn-112

1.4 E-3

2186

(18)

14.6 h

Nb-90

Mo-92

6.8 E-3

2186

(0.7)

17.3 m

Pr-144

Nd-145

9 . 1 E-4

2188

(0.5)

1.5 h

As-78

Se-80

1.1 E-4

2.2 E-4 Ca-40

1.6 E + l

2202

(26)

14.1 h

Ga-72

Ge-73, Ga-71

3.1 E-l

2205

(0.03)

6.7 d

Lu-172

Lu-175

2.9 E-6

2212

(0.1)

35.3 m

Sn-111

Sn-112

1.4 E-3

2212

(0.4)

3.12 h

Ag-112

Cd-113

6.4 E - 5

2213

(0.4)

77.3 d

Co-56

Ni-58

5.3 E-6

2215

(19)

41.5 h

Ir-188

I r - 1 9 1 , Pt-190

1.5 E-4

2222

(0.6)

14.6 h

Nb-90

Mo-92

2.4 E-4

2226

(0.9)

1.5 h

As-78

Se-80

2.0 E-4

2231

(?)

77.3 d

Co-56

Ni-58

9

2231

(0.2)

55 m

Cd-105

Cd-106

1 . 1 E-4

298 T a b . 5-5, continued T a r g e t Nuclide

Ν ' I

E.keV (1%)

Τ

Nuclide

2240

(2)

15.97 d

V-48

C r - 5 0 , V-50

6.4 E-6

2243

(?)

15 h

Na-2 4

Mg-25, Na-23, Al-27

9

2250

(0.5)

55 m

Cd-105

Cd-106

2.7 E-4

2252

(0.4)

1.65 h

Ru-95

Ru-96

6.9 E-2

2261

(0.02)

206 d

Rh-102

Rh-103 , Pd-104

9 . 4 E-6

2274

(2)

55 m

Cd-105

Cd-106

1.1 E-3

2276

(0.1)

77.3 d

Co-5 6

Ni-58

2283

(?)

32 m

Cl-34m

Cl-35, K-39

1.3 E-6 ?

2301

(0.5)

55 m

Cd-105

Cd-106

2.8 E-4

2319

(82)

14.6 h

Nb-90

Mo-9 2

3 . 1 E-2

2325

(0.2)

35.3 m

Sn-111

Sn-112

2.8 E-3

2325

(1)

1.65 h

Ru-95

Ru-96

1.7 E - l

2333

(2)

55 m

Cd-105

Cd-106

1.1 E-3 1.1 E-4

2348

(0.9)

40.2 h

La-140

La-139

2354

(49)

8.3 m

Ga-74

Ge-76

2.3 E-3

2376

(32)

20

Rh-100

Pd-102

8 . 3 E-3

2394

(0.2)

55 m

2426

(6)

6.6

2491

(8)

2507 2508 2522

h

Cd-105

Cd-106

2.2 E-4

Al-2 9

Si-30

9 . 1 E-2

14.1 h

Ga-72

Ge-73, Ga-71

1.0 E-2

(1)

3.12 h

Ag-112

Cd-113

1.6 E-4

(13)

14.1 h

Ga-72

Ge-73, Ga-71

1.6 E-2

(3)

40.2 h

La-140

La-139

3.6 E-4

2523

(1)

2.58 h

Mn-56

Mn-55, Fe-57

3.7 E-3

2526

(0.08)

55 m

Cd-105

Cd-106

4.5 E-5

2530

(3)

20 h

Rh-100

Pd-102

7.9 E-4

2 547

(0.1)

40.2 h

La-140

La-139

1.2 E - 5

2599

(17)

77.3 d

Co-5 6

Ni-58

2.2 E-4

2600

(0.1)

6.24 d

Bi-206

Bi-209

2.9 E-6

2616

(0.1)

20 h

Rh-100

Pd-102

2.6 E - 5

Se-80

1.3 E-4

m

2617

(0.6)

1.5 h

As-78

2632

(0.1)

15.5 m

Mo-91

Mo-92

2.7 E-4

2637

(?)

15.5 m

Mo-91

Mo-9 2

?

2642

(15)

2.6

Nb-99

Mo-100

2.9 E-2

2657

5.0 E-2

m

(0.2)

3.92 h

Sc-44

S c - 4 5 , Ti-46

2658

(1)

2.58 h

Mn-56

Mn-55, Fe-57

3.7 E-3

2675

(1)

5 h

Ho-160m

Er-162

9

2681

(2)

1.5 h

As-78

Se-80

4.4 E-4

299 T a b . 5-5, continued E . k e V (1%)

Τ

Nuclide

T a r g e t Nuclide

Ν ' I 3.2 E - 5

2686

(0.2)

3.2 h

Ag-112

Cd-113

2730

(0.8)

33.5 m

Ag-104m

Cd-106

1.0 E-4

2731

(0.02)

36 h

Ni-57

Ni-58

2.0 E-4

2734

(0.6)

108 d

Y-88

Y-89,

2740

(4)

53 m

Tc-94m

Ru-96

3 . 0 E-4

Co-56

Ni-58

9

2742

Zr-90

6.6 E-4

(?)

77.3 d

2754

(100)

15 h

Na-24

Mg-25, Na-23, Al-27

2.5 E - l

2785

(0.3)

20 h

Rh-100

Pd-102

7.8 E-5

2794

(?)

32 m

Cl-34m

Cl-35, K-39

9

2804

(0.1)

36 h

Ni-57

Ni-58

1.0 E-3

2829

(0.4)

3.12 h

Ag-112

Cd-113

2916

(?)

20 h

Rh-100

Pd-102

6.4 E - 5 ?

2939

(0.3)

26 h

As-72

Se-74

3 . 0 E-6

2960

(0.3)

2.56 h

Mn-56

Mn-55, Fe-57

1 . 1 E-3

300 5.3.5

In

table

Competing reactions in photon activation analysis

5-6,

all analytically

relevant

competing

reactions,

i.e.

reactions

of

different target elements leading to a common product nuclide, are presented.

In

the

first

column

the

reaction

pairs or triplets are listed in the order

of

the atomic number of the common product nuclide.

The quantitative contribution values in the second column are calculated assuming equal target element masses. These values are normalised to add up to unity in each

possible

interference

case

(Segebade et al."®^;

similar

investigations

were made by Berthelot et al**·®® using 44 MeV-bremsstrahlung). In the case of participating

neutron reactions the contribution

values have to

be taken as estimates, same as the corresponding N-values in table 5-2. In addition

to either competing

yet a third

type of interference,

product nuclide,

reactions or overlapping namely the secondary

gamma-rays there

is

decay into a common

e.g.:

48Ti(y,

p)47Sc

5lV(y,a)47Sc

48Ca(y,n)47Ca

These interferences for zero decay

are

period.

4 7 Sc

not included in this table; The

the given

data are

different types of interference including

due to secondary decay are discussed in detail in chapter 6.2.

valid

the one

301

r 0>

tu

0 υ ο t Ü ιΛ /—Ν LO c CM Οι

Φ ta

η

c

Ο Ο 00 ιΟ C

V φ Εκ

Ο υ σ> ιΛ

Φ b

>ν 0 υ

2 00 ιο

σ> ιΛ

0 Ο 00 irt 'S. C j«.

Ζ ο CO

0 υ 00 in

Ο U ο CD

e Ö

0 ^Ο co

α

£

c s '

3 Ο C3 CO

Ο ο σ> in

ζ ι—I CO

0 υ ο CO

3 Ο Οί CO

-—\

c β

C

£

A >—'

3 Ο in CD

3 (J oo CO

3 Ο

3

Ο

«

CO CO

CO α c

o,

£

c 3 Ο in CO

c Ν CO

3 U

3 Ο CD CD /—\

3 Ο

·»

CO CD /-N e

·

£

>w 3 u in CO

e OJ cCD

Q. C V-/ c Ν CO CO

3 Ο CO /—\ c β >• '—'

a Ο σ> CO

ι Μ Ο Α

Ο αϊ

Ο 03 c

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high.

and in part-

i c u l a r 7 7 4 ) . Excessively high extraction temperatures have to be avoided in any case to provide lease

of

sample

minimal volatilisation of components

oxide (see R e f ' s . 7 7 4 ,

775

and

crucible and

thus

reduce

prevent

gettering

undesirable of

re-

radiocarbon

).

Unlike conventional techniques the radiochemical analysis does not require fluxes with as low as possible and reproducible contents of the determined

ele-

ment. Frequently fluxes have been used whose inherent carbon has been utilised as an inactive carrier to ensure quantitative transport of the ^ C O g to the absorbent. Prior to its absorption the gas has to be cleaned from any unwanted

338

component,

e.g.

of

2,

the

1:lC0

described

Fig.

dust of a n y kind and p r o v e n i e n c e . the

sorption

vessel

is readily

A f t e r quantitative transfer

counted

using

the

spectrometer

above.

6.1.3:

Oxidation fusion apparatus f o r separation of r a d i o c a r b o n ;

explanat-

ion see t e x t

The irradiated

sample ( e v e n t u a l l y

amination

placed

-

is

in a

boat

t o g e t h e r with a f l u x ) - a f t e r s u r f a c e (1)

or

c r u c i b l e which

is pushed

decont-

into the

hot

zone of a f u r n a c e ( 2 ) w h e r e it is heated t o the t e m p e r a t u r e needed f o r complete combustion of the sample. lected

with r e s p e c t

T h e material of t h e boat o r the c r u c i b l e must be s e -

to its p h y s i c o - c h e m i c a l

b e h a v i o u r against the sample matrix 71 Q

material

under

the

required

w e l l as alumina o r z i r c o n ' ^ .

reaction

boat and

Silica

damage of the reaction

tube

in i n e r t atmosphere

sample is then burned under a controlled tube.

been

used due

as to

E x c e s s i v e sample mass might cause melting of (3).

After

closing

s a m p l e - f l u x m i x t u r e is heated to the d e s i r e d t e m p e r a t u r e . times is p e r f o r m e d

has

T h e total sample mass is somewhat limited

its e v e n t u a l e x o t h e r m i c o x i d a t i o n . the

conditions.

to p r e v e n t

early

the t u b e

(4)

T h e premelting oxidation.

The

melted

( 9 ) flow of o x y g e n passed t h r o u g h

A t y p i c a l f l o w - r a t e is s e v e r a l h u n d r e d milliliters p e r m i n u t e ^ · ^ .

the

some-

The

the gas

339 stream traps

coming from the reaction tube outlet is lead through to

remove

undesirable

contamination,

e.g.

several cleaning 7 Sil siica-wool or an acid

s c r u b b e r 7 3 7 f o r g a s - b o r n e particulate ( 5 ) , MnC>2 for absorption of S 0 2 ,

Br2,

F2719,

silver wool for h a l o g e n s 7 5 6 » 7 7 5 (6) (see also below in the section about

carbon

analysis in alkali metals). Desiccating a g e n t s ,

t h e gas stream

e.g.

Mg(C104)2719

dry

( 7 ) . Eventually residual CO is then oxidised in c u p r o u s oxide,

Schütze-reagent

(iodine pentoxide on siica gel) or o t h e r oxidants ( 8 ) . The gas

flow at the outlet is controlled by flow-meter ( 9 ) . The evolved **CC>2 plus c a r rier trap

gas 719

can

then

be t r a p p e d

either

by

a liquid

nitrogen-cooled

or by chemical absorption in any alcaline sorbant

multiloop

(10). The latter col-

lection method has been p r e f e r e d by t h e most w o r k e r s . Sodium hydroxide or a s c a r i e (NaOH sorbed in a s b e s t o s ) have mostly been used as collectors. A 77S thorough s t u d y of t h e C 0 2 sorption mechanism was carried out by Marschal et al. . The sorption vessel is then t r a n s f e r e d to the gamma spectrometer where t h e annihilation quanta a r e counted. Usually a coincidence s e t u p ( F i g . 6 . 1 . 1 ) is used. Another

technique

f r e q u e n t l y applied

is the

fusion separation

consisting

of

melting t h e sample in a mixture of oxidising chemicals u n d e r a stream of inert gas or o x y g e n 7 2 7 . This method has been mainly performed for a simultaneous a n a l y s i s of carbon and n i t r o g e n 7 5 0 ' 7 7 5 ; see F i g . 6 . 1 . 4 .

Fig. 6 . 1 . 4 : Oxidising fusion a p p a r a t u s used f o r separation of radiocarbon and radionitrogen under oxygen or i n e r t gas flow; explanations see text

340 The sample and the oxidising mixture, e . g . PbgO^ plus B2O3

is placed into a

crucible ( 1 ) which is heated under inert gas atmosphere by an induction furnace (2).

The gas flow (3) i s adjusted to 100-200 ml/min. 7 5 8 .

The extracted gas is

then cleaned as described above ( 4 , 5 , 6 ) . Copper, heated to about 500°C (7a) r e duces nitrogen oxides to Ng. CO is oxidised with CuO ( 7 b ) . Finally, a f t e r oxidation of any eventually residual CO by Schiitze-reagent or Hopcalite (8; a mixture of maganese dioxide,

cuprous oxide and silver oxide;

Hopcalite can also

serve for selective sorption of

15

0;

see 7 7 ® and below in 6 . 1 . 5 ) the gas mixture

contains carbon dioxide, elemental nitrogen and carrier gas only. The further processing of N2 containing radionitrogen is described in the next

paragraph.

The carbon dioxide containing radiocarbon is then trapped and counted as described above. As touched on above,

a mixture of lead tetroxide and boron trioxide has f r e -

quently been used as an oxidising m e l t 7 7 ® · 7 7 7 " 7 ® ® , but others have been reported as well ( e . g . 8 9 1 ) .

xhe

me

l t has a multiple function, e . g . as to provide

an oxidising environment of the sample, to prevent the formation of a passivating oxide l a y e r , to ascertain proper heat transport and more. Marschal et a l . 7 7 ® and Fedoroff et al. 7 ®^ published thorough studies about the separation mechanisms in the different oxidising melted media. - Carbon in alkali metals The analysis of carbon in alkali metals basically is performed as done in other matrix, namely by oxidising fusion. However, due to the peculiar physico-chemical behaviour of the alcalines, the analysis procedure has to be somewhat modified.

Bock

et

al.reported

inert

simultaneous separation of ^ C and

gas fusion

with an oxidising

flux

for

from sodium. The apparatus setup is s i -

milar to that used for other matrices (see above; oxidising melt f u s i o n ) . 779

Mostly, however, the system described by Lutz and D e S o e t e ' " which is based upon a method proposed by Kallmann and Liu 7 ®^ has been used with a few modifications according to the different analysis requirements.

This separation

sy-

stem is illustrated in F i g . 6 . 1 . 5 . After irradiation bearing

and surface

substance,

e.g.

treatment

the

sample,

inactive sodium carbonate,

together

with a c a r r i e r -

is tranfered into a silica

crucible ( 1 ) which is then introduced into the combustion flask ( 2 ) . The sample is heated slightly under oxygen flow. During combustion the connection between

341

to water aspirator

Fig.

6.1.5:

Apparatus

used for separation of radiocarbon

( a f t e r Lutz and D e S o e t e

t h e reaction

722

from alkali

metals

) ; explanations see text

vessel and t h e first absorption bulb (3) is closed by a stopcock

which is r e - o p e n e d a f t e r complete combustion.

Dilute s u l f u r i c acid (4) is then

slowly a d d e d . ^ C C ^ is t h e r e b y evolved; the inactive C 0 2 due to t h e sodium carbonate c a r r i e r a s s i s t s in complete flushing of all radiocarbon dioxide from the combustion f l a s k . The first absorption bulb (3) contains a cleaning a g e n t , boric acid to a b s o r b radiofluorine.

As described

in 6 . 1 . 2 . 1

(internal

e.g.

stand-

a r d s ) , radiofluorine produced from matrix sodium (see T a b . 6 . 1 - 1 4 ) sometimes has been used a s an internal monitor, but normally a p p e a r s as a source of i n t e r f e r ence d u r i n g light element analysis of sodium.

It can as well be absorbed

by

o t h e r a g e n t s (see 6 . 1 . 3 . 3 , e r r o r s o u r c e s ) . The second absorption bulb (5) contains a C 0 2 s o r b e n t , e . g . sodium hydroxide solution, where all carbon dioxide is completely a b s o r b e d . This is then counted a s described above.

342 As already noted,

multiple variations of the above described setups have been

worked out and reported. In T a b . 6 . 1 - 2 examples of the different applications of oxidising

fusion for photon activation analysis of carbon are summarised com-

prehensively including several relevant information.

343

0) a c φ Li Φ 05 β Ζ

Ό C CO

cd Ζ Φ 3 '3 3 Li ο X

Li 03 Εφ OS

Li CO 3 σ

CO Ο ο CM υCM υCM φ CO CO •ο Ζ Ζ C CO ΛU Ο

ω

Li φ C Li 3 £5 CO CO bo

3 Ο •Ο α

Sα α CO ο CO

C ο 4-· CO L< C αO

Ο

CO Ο Λ

•α c CO

φ 3 '3 3 Ο

•

to Li Ο CO « •o φ c to 3. le 0 α α C LiO Εο to s CM Li Ζ s CO 3 CO er Li a 0

φ J3 α CO to Ξ eg — ι( • -Ξ Ο Μ

•

(0 C O φ Li — ο in CM i-H

£

Φ > 'Ed Ο c

to 3 CM Ο Ο

ω to 0 3 c Ξ Β5 φ 'Li β CJ (0 CO

Li Φ c Li 3 XI CO CS to

CM ο Λ C — ιMΙ

aφ

Ε

ο ο CO Ζ

a Ζ

c-s Ο ΟCM ^ α ο ^ ι οco Λο S3 CO α- ζ

Ο ζ CO Ζ α Ζ

Ο co α Ζ Ζ

οto

< to

•Ο α.

ta S

344

α Φ ί, α,

C Ο a CO c εί*

ο ο Μ

α

c

ο ο) h αϊ Ο. 0)

ία ε 3 ο σ fH as ε ω ο C φ

U

ν «Μ φ 0J

ο. ε

C O to

Φ

C

Ο ο

ο

CO

Η

C O 'co α C;-. ο ο ο — ι» ο C3 rH CSJ Ο

Ο •ο 3 'ο 3 s«. Ο 2

Χ 3

Ξ

Μ I Ο IM η ο ί3 cu ·° α,

l·,

1 οΓ

ν bo Ä Λ 0. C hO bo

•fi

rH X ο Μ

a ο C O α

κ Ο

c 0) ω ο c —. ο ο in

Ό 0) c £ ω α > α> ω α C O

ΐ

-

2- * 2 £ bß φ

ω 3. β Ζ

ω •G 3. α C O ω

Φ

Ω

Φ

C 3

Λ

ο 0 C C

C O 0 α) c to

ο CQ "J· Ο •Ο

Ο ζ« Ζι Χ ο co Ζ

Λ a

CO

C O C O φ, C ο in C O ι-Η

ο ο CO kl


αϊ Ο U

»

•α a η Ξ cö S> ·>

ε

•a to 2 * caö -aο· ^ o ο· b

Ο a Ζ


Sο3 0) α

®

J3 cUaö to

< "Si

ΙI tI ^

α


ω

α εν

C 0) > CS b e Ο ιCS Ζ 0G ΟC CO esMΟ 2I Ο H η C Ο Ζ ΟΝC M α 0 Ζ ο Ό

•—.

ο Λ

•α υ3 C C ο ο

Ό Λ Η

υα α> bo J3 bo 3. Η "Ο ο, -ιΟ

e Ν

tJJ < CJ N

c Ν

α, α! ο

2 in t h e collecting

to a s c e r t a i n

vessel.

By

a sufficient

The radiocarbon ties,

in t h e

particularly

dioxide a r e

removed

chemical a n a l y s i s critical

cases,

counting

li, + -emitters; by

the

vessel

normally different

procedure

is contaminated

radioactive

other

than within

of

the

I f t h e s e contaminants a r e n o n - p o s i t r o n

i s ruled

by c o i n c i d e n c e c o u n t i n g ,

cessively ed for the

high.

If t h e contamination

positron-emitting

contamination

u t e s it c a n n o t be a c c o u n t e d f o r ; to

be

reconsidered7"'7. analysis.

might

Although

counted

it can

with

18F

(see

might ιA

Therefore,

6.1.6.3) result

F has

in

this

different

instance

been

s i l v e r wool ( B o c k et a l . all,

the

contamination

loss of s i g n i f i c a n c e

separated

by

radiocarbon

,

Marschal et

recovery

has

al.

775

mostly

is

the

(109.7

energies,

if

con-

minutes) say

more

^Νβ(γ,αη)

from

of t h e

of the

different agents,

zirconium o x y c h l o r i d e 756

However,

in the c a s e of so-

half-life

bremsstrahlung

high-level

in s e v e r e

( L u t z and D e S o e t e 7 · ^ ) ,

All in

and

ex-

be a c c o u n t -

noted in 6 . 1 . 2 . 5 .

with radiofluorine

greatly

be troublesome since at high

matrix

was

influence

l e v e l is not

than 30 MeV , it is produced in s i g n i f i c a n t amounts through the

fraction

in

with a h a l f - l i f e close t o 20 min-

problem

fraction

having

radio-

in t h i s c a s e t h e purification p r o c e d u r e has

A particular

tamination of t h e r a d i o c a r b o n dium

decays

the

However,

emitters their

is p o s i t r o n - e m i t t i n g

activi-

radiocarbon

6.1.4).

if t h e contamination

by d e c a y - f u n c t i o n a n a l y s i s a s a l r e a d y

import-

other

steps

reported7"17. out

with

activities

contamination

residence

78"*).

purification

(see also F i g ' s . 6 . 1 . 3 and

has

adjust-

T h i s i s of p a r t i c u l a r

a n c e if a liquid n i t r o g e n - c o o l e d t r a p i s used ( s e e e . g . 7 1 9 ' e)

proper

^C-fraction

carbon

namely

signal,

b o r i c acid

(Nordmann et a l . 7 ^ ' 7 ^ )

and

). been

reported

to be

around

100%, e x c e p t in a few c a s e s , e . g . in the a n a l y s i s of sodium as r e p o r t e d by Bock 7 SΚ o r in t h e c a r b o n determination in molybdenum r e p o r t e d by Schmitt and

et a l .

Fusban737. during

Many w o r k e r s

separation

and

have i n v e s t i g a t e d the radiochemical b e h a v i o u r of 77K collection ( s e e e . g . Hislop and Williams and various

publications of Engelmann and c o - w o r k e r s ) and many have c a r r i e d out r a d i o a c t i v e t r a c e r s t u d i e s o f t h e d i f f e r e n t mechanisms. bears

the

However, the application of t r a c e r s

d a n g e r of n o n - r e p r e s e n t a t i v e n e s s ;

in s e v e r a l c a s e s

they

might

show t h e same b e h a v i o u r a s t h e determined element in t h e sample matrix

not

(see

356

e.g.

CJQO ) . However, normally they have been applied successfully

as f a r as it

could be verified by analysis of certified r e f e r e n c e materials. 6.1.3.4

Sensitivity

The i n t r i n s i c sensitivity of the carbon determination primarily d e p e n d s , as was stated in 6 . 1 . 2 . 6 , on the i n t e g r a t e d cross section of the reaction used for a n alysis,

the actual electron e n e r g y and the mean electron beam c u r r e n t of the

bremsstrahlung source.

In T a b . 6 . 1 - 5 i n t r i n s i c sensitivities at d i f f e r e n t incid-

ent b r e m s s t r a h l u n g e n e r g i e s a r e given. The actual sensitivity is influenced by many o t h e r p a r a m e t e r s , as also was explained in 6 . 1 . 2 . 6 . T h e r e f o r e , one would expect r e p o r t e d detection limits of carbon analysis to v a r y g r e a t l y . according to the l i t e r a t u r e inspected

by the a u t h o r s ,

However,

t h e r e is a remarkable

agreement of t h e achievable sensitivities between many of t h e d i f f e r e n t working groups.

In comparing laboratory sensitivities in photon activation analysis of

carbon one has to bear in mind that at electron e n e r g i e s around 30 MeV photon activation is performed in the close vicinity of the giant resonance e n e r g y r e gion and t h u s small electron e n e r g y s h i f t s might r e s u l t in huge d i f f e r e n c e s in the induced a c t i v i t y . Reviewing the l i t e r a t u r e , it is sometimes difficult to compare sensitivity information since values either a r e given in terms of absolute minimum detectable masses or concentration limits. Some a u t h o r s , giving minimum detectable concent r a t i o n s , do not mention the total sample mass, and o t h e r s , publishing d e t e c tion limits in terms of absolute mass units, have calculated them using d i f f e r ent criteria, be it a pulse number limit or, more informatively, C u r r i e ' s 78S 7«fi criterion ' , or do not give any calculation basis at all. Anyhow,

it a p p e a r s that the detection limit f o r photon activation analysis of

carbon performed instrumentally varies from 40 nanograms to five micrograms. If one can quote a value of maximum agreement, it is one microgram (20 min e x p o s u r e to 30 MeV b r e m s s t r a h l u n g , mean electron beam c u r r e n t of 100 microamperes, and measurement a f t e r a total decay period of 20 m i n u t e s ) . The individual d e tection limit is,

of course,

contingent

upon the chemical i n t e r f e r e n c e activi-

ties of the sample components o t h e r than carbon, particularly the main constituents. In

the

radiochemical

approach

reported

sensitivities

(in

terms

of

detection

limits) r a n g e from one to 500 nanograms q u a s i - p e a k i n g at 20 nanograms. Normalised to the above described experimental conditions, the r e p o r t e d data a r e more

357 consistent analysis

than

those

sensitivities

given

for instrumental

analysis

suffer from chemical interference

since in

radiochemical

to a much lesser

ex-

tent.

Table

6.1-5:

Sensitivity of carbon

detection by photon activation,

normalised

to 100 microamperes mean electron beam current and 20 minutes irradiation period as a function of the electron energy

Eg-(MeV)

(Nordmann^^^).

sensitivity (yg C)

25

0.48

30

0.13

35

0.048

40

0.024

45

0.017

50

0.012

55

0.010

60

0.008

358 6.1.4.

Nitrogen

The analytically exploited nitrogen reaction

I4N(y,

n)13N

Τ = 9.96 m

has a threshold energy of 10.55 M e V 7 5 · * · 7 5 4 . Although having, like the carbon reaction,

a comparatively small integrated cross section,

nitrogen can be ana-

lysed very sensitively if high-efficiency fast separation steps are included in the analysis procedure. At

comparable

sensitivity

requirements,

the

chemical

separation

of

nitrogen

from the matrix must be considerably s h o r t e r than in radiochemical carbon determination. However, since mostly the same separation method, namely oxidising fusion,

is

applied

for

both

elements,

detection

limits

for

nitrogen

analysis

usually have been reported to be higher, typically about 50 nanograms. 6.1.4.1

Non-destructive analysis

The instrumental analysis of nitrogen is more problematic than that of carbon since it

underlies

multiple interference

the decay function cannot be resolved,

(see

6.1.4.3)

and in the most

cases

particularly if trace determinations are

7 Oft

to be carried out

. Therefore,

nitrogen can be analysed instrumentally in e x -

ceptionally favourable cases only, e . g . in very high purity beryllium 4 ®. If nitrogen material,

has been analysed instrumentally in organic or other

irradiations

frequently

were

carried

out

at

than 19 MeV to exclude the carbon reaction (see e. g . 7 1 4 ,

electron

carbon-rich

energies

less

. 7fi4

Instrumental analyses of nitrogen 45,761 (beryllium), monds),

764

were reported

by Engelmann

(several high purity elements),

Schmitt et a l . 7 1 5

(general),

Rocco et a l . 7 1 4

(dia-

(air dust f i l t e r s ) . A very interesting application7 8 7of

instrumental nitrogen analysis by photon activation is described by Meijers'° . Relative age determinations of fossile bones were performed on grounds of the nitrogen/fluorine weight ratio.

359

6.1.4.2 In

Radiochemical analysis

metals,

nitrogen

normally

is

present

elementally;

during

heat

extraction

mostly no chemical reaction of nitrogen takes place. It is evolved as N2 or 1ο N2 from the melted matrix. It can be analysed simultaneously with carbon by oxidising fusion under oxygen or inert gas atmosphere

777 77ft

'

770 70Q 70Q

with oxygen

by

reductive fusion under vacuum

sphere776,7®"'7^1. have been used,

o r simultaneously

or inert

gas atmo-

Generally the setups as described in the preceding paragraph

but different collecting agents for the active gas fractions. 792

Sometimes also the Kjeldahl method has been applied (Hashitani et al.

) . How-

ever,

in

as

is

explained

below,

this

entails

experimental

difficulties

some

cases. For better understanding of the mechanisms of the various nitrogen

extraction

methods generally applied, a thorough review article by G o w a r d 7 ^ is recommended. - Separation by the Kjeldahl method This

method rjn ο

nitrogen nitrogen

was

first

applied

for radiochemical photon activation

analysis of

. The irradiated samples are dissolved in reducing environment and is thus converted to ammonia, eventually

with the help of

catalysts,

e . g . mercury c o m p o u n d s ' ^ . The resulting ammonia containing ^ N is then e v o l v ed, separated with help of a carrier gas, e . g . argon,

purified and collected by

any means, and then counted using the spectrometer described in 6.1.2.3. This 7Ί0 method has been modified f r e q u e n t l y . E . g . Pronman et al. fused the samples in

sodium,

collected

the

ammonia

in

dilute

acid

solution

and

precipitated

with sodium tetraphenyle borate which was then counted (see also

it

Köhler 7 ®^). ι7

Carrier substances evolving inactive ammonia, e . g . ammonium chloride ed

to the

irradiated

sample

to ensure

quantitative

distillation

of

are addthe

active

gas fraction. Frequently the formation of different reaction products, v i z . ammonia, hydrazine, elemental nitrogen have been o b s e r v e d . This is surely dependent

upon the chemical form of the nitrogen originally

but

the experimental conditions obviously

composition

of the extracted

present

in the sample,

have much more influence upon the

nitrogen-containing

gas fraction 7 ®"'. However,

ensure quantitative collection on a unique sorbent, only one ^ N - b e a r i n g pound

has to be present.

elemental nitrogen gas795>

The easiest This

can

then

way is to convert be

eo

nected

in

all radionitrogen

m o lecular

to

com-

sieve cooled

to

360 with liquid nitrogen 796 . 77c Marschal et al. carried out a thorough study about the sorption mechanism of 1ο N 2 in molecular sieve. Nitrogen can be collected a s well on heated metal wool 7Ü7.7QÜ Q7fi or granulate, e . g . titanium or calcium where it is bound as nitride ιο^,οιυ^ The oxidation of nitrogen-hydrogen compounds (Nllg, NgH^) can be performed by heated cuprous oxide. Thereby its function is frequently double, namely to oxidise

n

C O to

11

C 0 2 and

13

N H 3 or

13

N 2 H 4 , respectively, to

13

N 2 in the case of

simultaneous analysis of carbon and nitrogen (see e . g . Fedoroff et al. The chemical yield is not always 100%. Depending upon many experimental parameters,

matrix material, chemical state of the nitrogen e t c . , it can be as low as

70% (see e . g . 1 7 ) . Frequently

poor

reactivity of several

been complained·'®*

matrix materials with the solvent

has

In these cases, the separation procedure consumes

too much time and thus the ICjeldahl method is not applicable because of severe loss of sensitivity. - Heat extraction As was mentioned in the introductory paragraph, oxidising or reductive fusion has been applied for radionitrogen extraction after bremsstrahlung

activation.

The oxidising fusion method is described in 6 . 1 . 3 . 2 . Carbon and nitrogen can be analysed

simultaneously using one extraction and collecting the gas fractions 11 ιQ to be counted ( i x CC> 2 and N 2 , respectively) stepwise selectively in suitable sorbents (see a b o v e ) . Molecular sieve cooled by liquid nitrogen has frequently been used for radionitrogen collection. It can also be caught by sorption with

heated calcium or titanium so a s to form the corresponding radionitrides Fig. 6 . 1 . 4 ,

(see

11).

Unlike in reductive fusion, nitrogen oxides might be produced during oxidising f u s i o n

2

^ ' T h e s e

are reduced by heated elemental copper (see F i g .

6 . 1 . 4 , 7 a ) . The reducing fusion procedure is basically the same a s the oxidising but usually is performed in graphite crucibles (so a s to provide large excess of reductant for oxygen extraction) under vacuum or inert gas atmosphere. This method is discussed further in the next section about oxygen analysis.

361 The heat extraction

method offers the following advantages

a s compared

to

Kjeldahl separation: - Normally heat extraction can be performed more rapidly; about 10-15 min. of total separation period have been reported; see T a b . 6 . 1 - 6 . -

Heat extraction

is quasi-universally

cedure the dissolution

applicable whilst in the Kjeldahl

step sometimes is too time-consuming

to allow

protrace

nitrogen analyses; there are very few reports about non-applicability of heat extraction. E n g e l m a n n ^ 2 found incomplete combustion of zirconium during heat extraction of nitrogen and therefore used the Kjeldahl separation procedure described above, dissolving the sample in hydrofluoric acid. 6.1.4.3

Reference materials; error sources

- Reference materials As also described in 6 . 1 . 3 . 3 (carbon analysis) the nitrogen reference s t a n d a r d s usually do not pass the separation procedure but are counted after separation of the analysed sample. It can be taken out of T a b . 6 . 1 - 6 that mostly boron nitride has been used as a reference; tially

mentioned

(stoichiometrical

this material meets all requirements ini-

purity,

resistance against

heat and

radiat-

ion attack, no interfering background produced, inexpensive; see 6 . 1 . 2 . 4 and 6.1.3.3). In several cases aluminium nitride was also used. On using this compound, if measured unseparated, one has to take into account considerable background a c 97 94 tivity by Mg and Na due to reaction with photoneutrons (see C h . 5 ) , whereas no considerable background activity is produced in boron nitride. However, the internal standard method cannot be applied if A1N is used, since the background activities mentioned above are due to neutron reactions and thus cannot represent any photon activation (see also 6 . 2 . 2 and 6 . 2 . 3 . 4 ) . Also the appication of

7

Be induced by ^ " β ( γ , ρ 2 η ) into BN eventually utilised a s

internal reference is riskful since lives

(53.4

days

and

9.96

minutes

functions (see also above 6 . 1 . 2 . 2 ) .

7

Be and

^N

respectively)

have largely different and

no parallel

half-

excitation

362

Beryllium

nitride

can also be used

Engelman and A l b e r t 2 4 .

as a r e f e r e n c e material as proposed

by

However, the use of beryllium compounds is somewhat

problematic because of t h e i r toxicity. Multielement r e f e r e n c e materials, as f a r as the a u t h o r s know, like e . g . in the analysis of carbon and oxygen,

Mylar

have not h i t h e r t o been utilised for ni-

trogen a n a l y s i s . For f u r t h e r discussion about the r e f e r e n c e material t h e r e a d e r might r e f e r to 6 . 1 . 3 . 3 above.

363

eg t-

cö in

φ 3 '3

C CT>

IQj 2« φ CO

Λ

L· co

•0 . λ ε ä β Λ υ Φ

3

Ο Ο

cd

ε ν Λ e φ ο c αι s* Φ 01 ti

>.

Φ > Ο •Ω

Λ α

CO

fc.

Φ Φ

CO

to 3.

Ό

0 S3 "

3

3.

α> α

Cu

ε

Ο 4-1

Ο CM

•Ο

φ

C

Ο

3 "Ο CO CO

"Ο •Ο CO

ο

bo •3

φ

Α CO

Ζ


ο

§ iχ

CO

Ζ

c a, .s to

CO Ο CM α

7

Ζ 3 ja a "3

^

—

οCO a

a. co CO CO to 3 v-t t< "3 Φ c '3 0

Λ

Χ

Ζ

—

N

ο Μ Ν ~ χ ζ

c

δ ζ £ cd •α

z

Μ

364

3 Β

C Ο A Α! (Η CO Α Α>

2

.2

α

Ο 4-» Α)

α Ο. Φ

SC 3.

A Φ Φ A CO

TU

0 C

Ο I—T

TO C

Ο C

C

Ζ Α

ιη

α

TC

Φ

fa Κ

Φ

CO

°ΐ Ö Ο ΙΛ Τ-Η

(

S

Ο Ο Ι-Η

0)

Φ

Χ

1

Φ Χ

Ι CO Ο

Ο

CO

fa Φ

CSJ

CQ Ι

CO

•Ο Α. CO Α TO

u Φ C

Ο

C^ Α Ι -Ί-

C Ζ

Ο

fa

•Ο Α,

Φ

,

Μ

CO CO Ω

CO 3 ST-I

• CO 3

—>

Ό

Φ C

Χ Ο

Μ


Ο Ο C-

CQ

8

Φ

Ξ*

fa

C

3 Ο Φ

fa

CO 3

fa

Ί< CO

Ο Ε

.9

Ό Φ 3 C *«-·

•Α C CO

•Α Φ

C

Ο

Ζ

SH Ο Φ Ο. CO

υ

Χ ^

>.

Ο

Ο

CO

u

Λ C Λ

Η Φ

FCJJ C Ο Α

CÖ A

CO

Ν* =3 ΊΠ CO Α Φ CO Ε

ο

Φ Ο C Ν !-, Ω

Ο 53

TU

Ο

Ο

Ο

'3 0

365

C

2 [φ

ο

Λ

L, CO a

>. Λ

CO

(4 S a

Φ

η

c ο

Φ

Ε φ •C ο

C

CO •σ Φ

ο c 0) φ

fc.

S οφ α.

Φ

es

to

ω c

ζ a

ζ

C

ca Ο

ω c CO

φ φ

CO

ο φ Ο

•Ω 0 Ξ

Φ Φ 03

Φ

Φ Φ

φ

KJ

CO

Ο

Λ SI




>

ω

'to Φ

h •α αι 3

C •*-» C

ο ο

Λ α Η

«

2 Ο Φ Ϊ3 •Ρ Λ >>

c

u

CO α, Φ

Β

Φ

Λ Ο α

Ε Φ

ω c

ο c Φ

φ *»-( φ

Ζ


c

3 Β

Β

φ

Β

c ω

£

to

ο

C


367 - Chemical i n t e r f e r e n c e In the most cases instrumental analysis of nitrogen is not possible due to multiple uncorrectable chemical interference by matrix components (see e . g . 7 2 ® ) ; furthermore, nitrogen analysis is interfered by oxygen and carbon activity. The decay curve of * 3 N lies between those of ^ O and nificance.

Since

the

activation

threshold

of the

than that of carbon, the interference due to ion at lower photon energies 7 *'*'

and thereby it loses s i g nitrogen

reaction

is

lower

might be excluded by activat-

but this bears the penalty of poor sensi-

tivity.

Tab.6.1-7:

Bremsstrahlung-produced radionuclides with half-lives close to 10 minutes

T(m) 6.1

Nuclide 82mBrl

Target

7.6

Mo

7.7

6.26

94mNb

95

6.46

^Br

79

6.6

29

A1 179m w

30

6.7 7.2

105m A g

T(m)

Br

81

Nuclide UlmIn 38 K

Target 112

Sn

3%,

Br

40

Ca

80

Se Fe

T(m) 10.3 10.5

Si 18 0W

8.2 8.51

53Fe

54

Ag, 106cd

9.46

2 7 r.lgl

27

A1

14.5

9.76

62

Cu

63

Cu

14.6

107

AS

7 9

14.4

Nuclide 95γ

96

60mCol

Zr

61

Ni,

59

Co

112

In

131m B a 1

0

W

Target

l

13

ln,

H4Sn 132

Ba

10°Mo

Iphotoneutron-produced

Among the numerous interference sources (see e . g . T a b . 6 . 1 - 7 ) impurities of copco per and iron yielding o i C u and " " F e , respectively, are the most prominent ones; particularly the copper reaction 63

Cu(y,n)62Cu

Τ = 9.76 m

has a comparatively large integrated cross section so that very small traces of copper impurity in the sample can make precise and accurate instrumental nitro gen analyses impossible. This interference, and also the interference by

54

Fe(y,n)53Fe

Τ = 8.51 m

368

c a n n o t be r u l e d out by e n e r g y selection since the t h r e s h o l d e n e r g i e s of both a r e close t o t h a t

of the

nitrogen

13.62 MeV a n d 10.55 MeV,

reaction

analytically

exploited

(10.84 MeV,

respectively).

Q u a n t i t a t i v e i n t e r f e r e n c e yield a s s e s s m e n t s were p u b l i s h e d b y E n g e l m a n n 7 2 ^ ' In radiochemical a n a l y s i s chemical i n t e r f e r e n c e normally is e x c l u d e d .

The a u -

t h o r s could not find a n y r e p o r t about s e r i o u s e r r o r of n i t r o g e n a n a l y s e s c a u s e d 13 b y contamination of the Ν a c t i v i t y f r a c t i o n by o t h e r a c t i v i t i e s . O t h e r s o u r ces of e r r o r

might e x i s t ,

particularly

during

Kjeldahl e x t r a c t i o n .

These

are

d i s c u s s e d below. - Nuclear i n t e r f e r e n c e Nuclear i n t e r f e r e n c e by n e i g h b o u r i n g elements can be avoided in photon a c t i v a t ion a n a l y s i s of n i t r o g e n

more easily than it is possible in c a r b o n

determinat-

ions b e c a u s e of t h e lower reaction t h r e s h o l d of t h e n i t r o g e n r e a c t i o n . regarding

the

required

sensitivity,

one o r

several

competing

However,

reactions

(see

T a b . 6 . 1 - 8 ) might p r o v e inavoidable since a c t i v a t i o n s f o r t r a c e a n a l y s e s have t o be c a r r i e d out f a r a b o v e t h e giant r e s o n a n c e e n e r g y .

Out of the r e a c t i o n s in

T a b . 6 . 1 - 8 , N o ' s . 2, 3 and e v e n t u a l l y 16, 17 a n d 18 might i n t e r f e r e s i g n i f i c a n t ly if i r r a d i a t i o n s a r e c a r r i e d out at a r o u n d 30 MeV e l e c t r o n e n e r g y . The o t h e r r e a c t i o n s normally can be d i s r e g a r d e d u n l e s s t h e t a r g e t element is a main matr i x component ( s e e

6.1.2.5).

T a b . 6 . 1 - 8 : N u c l e a r r e a c t i o n s by which

13 Ν is p r o d u c e d

Threshold No.

Reaction Ν(γ,η)13Ν

Threshold

(MeV) 1

No.

10.5

10

24t.lg(

25

11

27

Α1(γ,

(MeV) :

Reaction

1

14

2

16

ϋ ( γ , t)

3

19

F(r,6He)13N

24.4

12

27

Α1(γ,3α2η)13Ν

46

4

19

F(Y,a2n)13N

25.4

13

28

Si(y,15N)13N

26.9

5

20

7

14

31

Ρ(γ,180)13N

29

6

20

Ne(Y,at)

S(y,

7

23

Na(y,

8

23

Νβ(γ,2α2η)13Ν

9

24

η

13

N

Ne(Y, Li) 10

13

13

N

27.3

0

N Ν

25.6

N

29.8

15

27.5

16

13

C(p,n)13N

2. 5 2

36

17

12

C(p,r)13N

2.52

18

16

Μκ(γ, Β)

Ν

28

t a k e n out of R e f ' s .

56

-858

F)

0(p,a)

13

13

39

Be)13N 13

19

14

32

*taken out of R e f . 7 5 4 or calculated 2

13

13

Y,2at)

N

N

30

6. 0 2

369 1 Q

Yield values of reactions contributing to the common ed by Engelmann and c o - w o r k e r s 2 3 ,

756~75^.

Ν activity were publish-

As an example, Engelmann et a l . 7 5 ®

found after activation with 30 MeV bremsstrahlung 780 micrograms of oxygen giving, by ^ Ο ( γ , ί ) ,

the same activity of

like 1 microgram of nitrogen.

- Other e r r o r sources Error sources in the separation procedure of the radiochemical photon activation analysis of nitrogen - if performed by oxidising fusion - a r e less problematic than encountered in C or 0 analysis; elemental nitrogen gas is quasi-inert and not subject to adsorption during transport and incomplete collection in the sorbent

to a significant

Consequently, play such

degree as it might occur in the handling of

the nitrogen

an important

carrier eventually used

role as e . g .

^COg.

(see T a b . 6 . 1 - 6 ) does not

carbon-containing

fluxes in the

carbon

analysis 7 7 "*. Sometimes oxidising fusion was found to be somewhat more efficient than reductive If nitrogen

fusion777,793.

separation after Kjeldahl is used the analyst eventually has to be

aware of more sources of e r r o r ,

besides the insufficient

rapidity of the me-

thod. Anyhow, as also recommended for any other radiochemical separation procedure,

the chemical yield should be determined prior to analysis evaluation

by

use of either t r a c e r methods with doped samples or, more efficiently as mentioned in 6 . 1 . 3 . 3 , than

100%

are

by analysis of certified reference materials. obtained

this

might

have

the

following

If yields other

reasons

(see

also

6.1.3.3): a) The sample was not completely decomposed; this has frequently occurred during Kjeldahl separation, but sometimes was also observed in heat extraction (see

Ref.7^2).

It has been noted 77 ·* that Kjeldahl separation

incomplete if nitrogen

sometimes is

lies before as nitride of certain elements,

e.g.

Al,

Ti, V, Zr, Nb. The decomposition of these compounds sometimes is extremely difficult. This e r r o r source can mostly be circumvented by proper reselection of the separation conditions (flux, extraction temperature e t c . ) . b ) Radionitrogen did not appear as a unique compound; this has frequently been encountered during Kjeldahl separation, the

gas

mixture

after

Kjeldahl

but also in oxidising fusion.

extraction

ammonia and hydrazine in various ratios 7 9 "',

can

contain

elemental

Whilst

nitrogen,

the gas extracted by oxidising

fusion frequently contains nitrogen oxides. The easiest method to avoid r a dionit rogen losses is to convert all radionit rogen compounds into elemental

370 nitrogen

gas by oxidising or reducing media,

respectively,

and collect it

with a p p r o p r i a t e a g e n t s as described in 6 . 1 . 4 . 2 . c)

Radionitrogen

was not completely collected in the absorption vessel; this 1ο might be due to the production of more than one N-eontaining compounds as explained above. Otherwise,

if radionitrogen was collected as metal nitride,

the adsorption t e m p e r a t u r e might not have been properly a d j u s t e d or,

and

this

re-

might

sidence ient.

occur as well if molecular sieve collection is applied,

period

of the

nitrogen

gas in the collecting vessel

This might also be the case if ^ N

the

was i n s u f f i c -

was absorbed as ammonia a f t e r

Kjeldahl s e p a r a t i o n . d) The case of radioactive contamination of the counted fraction a f t e r s e p a r a t ion is discussed in detail in 6 . 1 . 3 . 3 , e r r o r sources section. Normally, if heat extraction has been used, yields around 100% have been r e p o r t e d . However, as already mentioned, the Kjeldahl separation p r o c e d u r e sometimes shows up as troublesome in terms of incomplete extraction or excessively long

duration,

spectively.

resulting

However,

in

eventually

inaccurate

Kjeldahl separation,

results,

re-

being the f i r s t of all nitrogen

or

se-

paration methods applied in photon activation analysis,

unprecise

is still used

success-

fully in many cases nowadays. See e. g . ^ 1 . 6.1.4.4

Sensitivity

For some general remarks about the achievable sensitivity the r e a d e r might r e f e r to 6 . 1 . 3 . 4 .

For the s t a n d a r d activation

conditions

half-life e x p o s u r e to 30 MeV b r e m s s t r a h l u n g ,

described above

mean electron beam c u r r e n t

(one 100

microamperes; total decay period 15 min) from 60 nanograms to five micrograms, q u a s i - p e a k i n g at one microgram have been r e p o r t e d a s a detection limit in instrumental nitrogen

photon activation analysis.

In the radiochemical

approach

from 10 to 700 nanograms have been f o u n d , mainly around 50 nanograms.

371

6.1.5

Oxygen

Oxygen was the first element to be analysed with help of photonuclear activation. Basile et al.® analysed oxygen in organic matter using the reaction

I6

0(y, n ) l 5 0

Τ = 124 s E I h = 15.67 M e V

induced by 18.6 MeV bremsstrahlung from a betatron.

The intrinsic sensitivity

of detection about equals that of nitrogen discussed above. However, appreciable

sensitivity

somewhat problematic; all

post-irradiation

of

oxygen

analysis

with respect

treatment

in

the

radiochemical

to the comparatively

steps,

viz.

achieving

approach

sample transfer and

uncapsulating,

surface contamination removal, separation of radiooxygen from the matrix, lection

in the absorption

containment

and

eventual

is

short half-life of

transport

to the

col-

detector

system, must be kept as short as possible. Instrumental analyses, however, are less problematic than those of other light elements,

e.g.

nitrogen;

according

to the literature reviewed by the authors, there are more reports about cessful

instrumental

photon

activation

determinations

of

oxygen

than of

sucany

other of the light elements. This is explained further below in the instrumental analysis section.

The above named photoneutron reaction has been exploited for analysis almost exclusively,

using coincidence annihilation quanta counting as also applied for

the other light elements.

The authors could find only v e r y few reports about

other reactions and/or counting procedures used in photon activation

analysis

of o x y g e n . In the pioneer work cited above® the authors applied positron count802 i n g , and so did Chepel et al. analysing oxygen in organic material. Measurement of the photoneutrons promptly emitted during photon activation of oxygen was p r o p o s e d ® ^ '

However,

in this approach the analyst is confronted with

the surface contamination problem as in conventional analysis. The same problem 71 Ω arises in the method described by Scherle and Engelmann

, who measured the

delayed neutrons emitted by ^ N produced through * ® 0 ( γ , ρ ) . However, using this method it is possible to determine

the isotopic concentration

which sometimes is of import, e . g . during biological research Oxygen

can be analysed

by nuclear methods,

ratio of

^0/lf>0

work.

photon activation in

particular,

more favourably than with other techniques, with respect to rapidity, 802 80*i ity and relative freedom from error sources ' .

sensitiv-

372 6.1.5.1

Noil-destructive analysis

Although instrumental photon activation analysis of oxygen is subject to interference of

any

special cases,

kind

to a lesser

extent,

it

can only

be carried out in

namely normally in high purity matrices.

very

This is true in parti-

cular, if trace analysis is required.

The application of this technique to oxygen analyses in organic matter o f f e r s itself

since the activation of the matrix carbon

can be excluded

by

selection

of an electron e n e r g y not exceeding 18.7 MeV ( s e e above, Basile et a l . 6 ) . However,

serious decrease of sensitivity has to be taken into account as a conse-

quence since the cross section maximum of the oxygen reaction is located at a relatively high photon e n e r g y . Moreover, chemical interference induced by other elements might be unavoidable also at low bremsstrahlung energies; see 6.1.5.3 and T a b . 6 . 1 - 9 .

Tab.6.1-9:

Bremsstrahlung-produced radionuclides with half-lives close to 2 minutes

T(m)

Nuclide

Target

0.99

2 5 Na

2 6 Mg

T(m)

Nuclide

Target

T(m)

1.7

57 Mn

5 8 Fe

3.4

Nuclide 140 p r

1.02

201m pb

204 p b

2.1

7 5 Ga

7 6 Ge

3.75

52 y

1.02

86m R b

87Rb

2.246

28 A1

2 9 Si

3.8

121mIn

1.03

141m Nd

1.075

17 f

142Nd

2.3

149m pr

150 N d

1.08

91m Mo

92

19 f

2.3

119In

1 2 0 Sn

2.41

108 A g

109 A g 31 p

MO

16 0

1.18

14o

1.2

114ln

1.2

lllmAg

1.68

185mw

2.5

30p

115In

2.5

53m pe

112Cd

2.55

137m Ba

186W

2.6

99Nb

3.9 4.16

Target 141 p r 53Cr 1 2 2 Sn

79mSe 89m Zr

80Se 90Zr

4.2

122m sb

4.3

77m B r

54Fe

4.4

118m2In

1 3 8 Ba

4.69

109m pd

1 2 3 Sb 79Br 1 1 9 Sn 110 pd

1 0 0 Mo

Instrumental photon activation analyses of oxygen were also reported by Breger et

al. 8 0 4 (semiconductor

Isserow762

(beryllium),

material), Evshanov

Beard

et al.

et

732

al. 7

(beryllium),

(beryllium),

(16>180

isotopic 7

Persiani et al.

muth mixtures),

Kusnetsov et

ratio

(caesium), al.807

beryllium), B e r r y 8 6 7 and others.

and

(alkali metals and alcaline e a r t h s ) ,

Holm and S a n d e r s 8 0 5 (sodium), Engelmann et a l . 8 0 6 (sodium), (beryllium),788

Gilman

determination), fiö

17,24,726,761,764

Albert

et 79ft

Mackintosh and J e r v i s

(iodine compounds),

Marsh 4 9

al.708,

763

(lead/ bis(lithium and

373

6.1.5.2

Radiochemical analysis

Two basic methods a r e available for chemical separation of radiooxygen,

namely

f i r s t , the classical r e d u c t i v e fusion carried out u n d e r vacuum or inert gas a t mosphere and

second,

isotopic exchange separation;

the latter

is

preferably

used f o r oxygen analysis in alkali metals. - Reductive fusion The a p p a r a t u s s e t u p is t h e same as utilised for oxidising fusion u n d e r vacuum or inert gas (see Fig. 6 . 1 . 4 ) . Graphite crucibles a r e used to provide a r e d u c i n g environment

so t h a t , initiated

by heating,

all matrix-inherent oxygen is con-

v e r t e d to carbon monoxide. This is carried by a vector gas t h r o u g h the f u r t h e r processing

stations as

described

above in the oxidising

fusion context

(see

6 . 1 . 3 . 2 ) . Inactive oxygen, either inherent to the g r a p h i t e crucible or the vector gas or t h e flux metal eventually a d d e d , s e r v e s a s a c a r r i e r so a s to obtain complete r e c o v e r y of radiooxygen in the collecting sorbant ( e . g . a s c a r i t e ;

see

6 . 1 . 3 . 2 ) . Platinum has been used f r e q u e n t l y as a flux in r e d u c i n g fusion 77 "^» 773,789 7

o t h e r , less expensive media might s e r v e as well in many cases (see

7

e. g . · * ) . Since g r a p h i t e crucibles a r e used a s combustion vessels, t h e r e is t h e possibility

of different ways of heating exploiting the electrical

conductivity

of g r a p h i t e ; except the above described f u r n a c e s (resistance o r induction f u r n ace; eventually gas b u r n e r ) other principles have been used, namely direct c u r r e n t carbon a r c h e a t i n g 7 1 6 '

773

>775>

789

> 8 U 8 o r h i g h - c u r r e n t impulse heating 7 3 ·*'

774,809^ π on

Nitrogen can be analysed simultaneously (see e. g. relevant l i t e r a t u r e , multaneously

) . However, reviewing the

nitrogen has mostly been analysed by oxidising fusion, si-

with carbon as described

in 6 . 1 . 3 . 2 .

In several critical

cases,

7 Μ 'Ϊ

incomplete extraction of nitrogen during r e d u c t i v e fusion was o b s e r v e d (Ref. and the relevant l i t e r a t u r e cited t h e r e i n ) . The above described instance,

p r o c e d u r e is not applicable for all matrix materials.

For

oxygen analyses of selenium carried out as described lead to i n s u f -

ficient r e s u l t s . Gösset and E n g e l m a n n 8 1 0 described a method in which seleniuminherent oxygen - most probably present as SeC>2, but possibly as S e 0 3 - is ext r a c t e d with elemental s u l p h u r either in t h e melt or in the vapour phase.

374

2Se Se

l5

15

S +

03

2Se

02

-

(S^O^O

02 +

Se +

S

S

15 I5

02

02

02

15

or other isotopical composition) i s then

collected in any appropriate s o r b a n t , sulfur

l5

02 + S ^ 15

Sulfur oxide produced thus

-

e.g.

hydrogen

peroxide,

whilst

residual

vapour is collected in an ice-cooled t r a p .

T h i s method is applicable to ι all matrix elements whose sulphides a r e chemically more stable than their oxides. R e d u c t i v e fusion tals. O x y g e n , ical reaction.

extraction

cannot

be used for oxygen

analysis in alkali me-

if present as alkali oxide will not undergo the above named chemT h e r e f o r e , other ways have to be used for oxygen separation

(see

below). - Oxygen in alkali metals The classical p r o c e s u r e s of oxygen separation from alkali metals, viz. amalgamation® 1 1 , dium

isolation

metal 81 "*

photon life of

and

activation 15

with

help

other

of

alkyl

halides812,

methods814»015,

analysis.

In the most

vacuum

distillation

a r e not applicable for cases

of

so-

radiochemical

this is due to the short

half-

0 and the considerable time-consumption of the above named methods,

respectively. QIC The technique

described

procedural variations,

by Lutz

has been applied,

in almost all c a s e s .

eventually

with

slight

It is based upon isotopical e x c h a n -

ge between inactive oxygen and radiooxygen. T h e a p p a r a t u s setup is presented in Fig.6.1.6. brought

After

into

of sodium

the

irradiation reaction

and

surface

flask(l)

which

contamination contains

removal the

several

tens

hydroxide solution where the sodium is dissolved.

sodium

of

is

milliliters

Nitrogen

gas a t -

mosphere is provided to exclude atmospheric oxygen a c c e s s . The matrix-inherent oxygen including radiooxygen is converted t o sodium hydroxide.

lsO

then e x c h a n -

ges with inactive oxygen in a water molecule t o form H . j 1 5 0 . By heating with a gas

burner,

water including

radiooxygen-oontaining

water

is distilled

into a

cooled trap ( 2 ) which contains a few milliliters saturated sodium hydroxide solution.

Eventually

o c c u r r i n g contamination

by radionitrogen-containing

( s e e preceding paragraph about nitrogen a n a l y s i s ; e r r o r sources

ammonia

section)

375

is removed H2150.

by

boiling.

The

distillate

should now contain

radiochemically

pure

It is adjusted to standard volume if necessary and then counted as d e -

scribed in the p a r a g r a p h s a b o v e .

Frequently

the

matrix

activity

of

the

residue

in

the

reaction

vessel

(1)

has

also been diluted to a standard volume and aliquots have been measured to o b tain an internal photon f l u x monitor as also described above in 6 . 1 . 2 . 1 , al standards

section;

see also® 1 5 .

determination

of carbonate-bound

The

described

oxygen;

procedure

however,

inten-

allows a separate

there are some limitations

due to the chemical behaviour of the carbonates. T h i s is discussed f u r t h e r b e low in the e r r o r sources section

Basically,

this

method

is

6.1.5.3.

applicable

to

all alkali

metals,

but

sometimes

fur-

t h e r countermeasures against too violent reaction of the metal with water might be necessary, al.^®;

e. g . in the case of caesium analysis as d e s c r i b e d b y Nordmann et

see also 8 1 ®.

T h e described

method can be applied to radiochemical ana-

l y s i s of materials whose elemental forms are readily

hydrolysable.

to water aspirator

Fig.

6.1.6:

Apparatus Lutz815);

for

separation

of

radiooxygen

from alkali metals

(after

explanations see text

In T a b . 6 . 1 - 1 0 some examples of radiochemical o x y g e n analyses are summarised.

376

φ Ο c φ f« φ φ οί Ε t-. Vο ο S αϊ* ,2 = β α C

C

b a) Ε Φ ω

•β c a

ο a ζ

os

•Φο

Sο

α)

φ α

α

C-, ο Μ

a a α a Ζ to 3.

2 "3

2φ

ε φ Ο

Α Ο

Α

ο

3.

Φ

c

Α

to

3.

Ο

Φ >»

α

03 ε φ ο C φ b φ «Μ

Π

2

ο a U 5 α Φ Ο]

χ

•ο c .. a

Ό Φ

Sο φ α

Ο

a ζ

fcO 3

θ" ω CVJ < § Φ

•α

C 3

Χ ο a Ζ

ε φ

3

α, a

Ο

ο.

σ"

•λ

ε

c ο Μ 3 (Κ

μ crt a τ

3 3 Ο

ι*

«2 C ^ Λ

Μ >

» a 60 Φ 3

5 tj Ο X

_3

Ξ

ε

Φ

Ο

a Ζ έ b Φ a

a •3 Ο Α

3

ο

-

Χ Ό Χι

Ο ΙΛ ~ Ν '·σ —

Ο

a Ζ ι ϊ- Ο φ U a β Ζ

rΟν Eil*

ο Ό

Ό Φ S*

•α Φ

ί*


ι—Ι Co'P Ο ο f—I c Ο"

03 ο

αϊ 2 'S

•a φ

t*

3 Ό

in CO ο ςο 00 «-»

cd Q Χ α

2 α>

>»

•

ε ω

Ο

c α>

UJ

ί* φ

Ο ^ ff-a ο

CO ο Λ CJ ΓΟ •a αϊ Ό CO t1 h Φ— cö Ο α Ο •a α> ο c CO CO Ε φ CO CO υ CO ο φ CO ι CO > t-H a ε

C ο

•α α

C

ο

a®

CO

α}

Ό C

cd

A .1

hfl

φ

3.

ο

c α)

ba 3.

tJO

3.

Ο

μ

ω

OS

•Ω

ν

ο α

α

C

φ

c

ζ

•α 3

Ο

a aj

a

Ο

S 3Ο ~

Ο Ε 3

. Ξ

Ο

%

>

T3

3 CO

5

—
CO

Ε

3 ο.

382

6.1.5.3

Reference materials; e r r o r sources

- Reference materials In the i n s t r u m e n t a l analysis of o x y g e n , f r e q u e n t l y mylar has been used as a r e f e r e n c e material. This can also be applied for simultaneous carbon and oxygen determination

(see

6.1.3.3).

Since one s t r i v e s for n o n - d e s t r u c t i v e

reference

material measurement in radiochemical oxygen photon activation analysis,

mater-

ials have been selected whose non-oxygen components do not i n t e r f e r e ; boron trioxide and beryllium oxide have been favoured (see T a b . 6 . 1 - 1 0 ) . In alkali metal analysis

appropriate

oxides,

hydroxides,

or carbonates

have

been selected since they usually have to pass the separation p r o c e d u r e so as to obtain the chemical separation

yield

(see below). Moreover,

the cation is s e -

lected so t h a t it can s e r v e as i n t e r n a l photon flux monitor. For more general information about

the

r e f e r e n c e materials see 6 . 1 . 2 . 4

and

6.1.3.3. - Chemical i n t e r f e r e n c e Due to f r e q u e n t chemical i n t e r f e r e n c e instrumental analysis of oxygen (as well as of a n y o t h e r of the light elements) is possible only in a few favourable c a ses.

In

Tab.6.1-9,

a

selection

of

possibly

interfering

nuclides

produced

t h r o u g h b r e m s s t r a h l u n g activation are l i s t e d . Out of these, several have been studied in more detail since they f r e q u e n t l y i n t e r f e r e . a) I n t e r f e r e n c e by

on

Ρ on

At normal, say 30 f.leV, b r e m s s t r a h l u n g energies

Ρ can be produced at s i g n i f i -

cant levels by 31

P(y,n)30P

Eth = 12.32 MeV

32

30

S(y, n p ) P

Eth = 21.18 MeV

35

Cl(y, α η ) 3 0 Ρ

E,h = 19.31 MeV

The influence by s u l p h u r and chlorine, respectively, can be minimised by i r r a d iation at lower e n e r g i e s . However, this entails s e v e r e loss of s e n s i t i v i t y .

383

Moreover,

the interference

by

phosphorus cannot

be outwitted

thereby.

This

source of interference was studied thoroughly by Engelmann and c o - w o r k e r s ^ ' 723, 726, 806. s e e a l s o 2 1 , 142, 728.

b ) Interference by

38 Κ

This interference is of particular relevance during instrumental oxygen

analy-

sis in lithium or sodium, since the according target element, namely potassium, oo is likely to be present as matrix contaminant in considerable amounts. Κ can also be produced in calcium containg matrix by

40Ca(y

different in half-lives, the decay functions of

, n p ) . Although being quite

and

cannot be properly Q np

resolved if trace oxygen is to be analysed. Engelmann and Loeuillet

recom-

mended anti-coincidence counting refering to the characteristic gamma-ray line no of J O K . This method can well be applied in other interference cases but, as alQQC ready was mentioned in other context

, requires additional hard- and software

effort. c ) Interference by aluminium If

oxygen

is

analysed

non-destructively 97

found to i n t e r f e r e ,

e.g.

in

aluminium

several

nuclides

were

94

Mg,

Na and

Al. The latter can be produced by

7 ^ ΠΩΑ 1 ( η , γ ) as well as by silicon mostly present in normal aluminium, through S i ( y , p ) . Also copper is frequently present in considerable concentrations,

hence

must eventually be taken into account as source of e r r o r . See also

Although the gamma signals of the above mentioned radionuclides are discarded to a large extent by coincidence counting their integral activity creates deadtime problems and quasi-coincidentally absorbed gamma-rays might produce a considerable background. The above mentioned interference sources normally are relevant only in instrumental photon activation analysis of o x y g e n . However, also in the radiochemical approach

frequently impurities of

the counted

fraction have been

complained.

Radioactive contaminants sometimes pass the purification steps unretained and thus radiochemical purity of the counted fraction cannot be assumed. Frequently 1 contaminations by the light element product nuclides have been o b s e r v e d . Ν compounds can be expelled from theο 1 collecting agent by reduction to ammonia and ο subsequent evaporation (see e. g . ) , but thereby the total decay period is considerably prolonged and consequently there has to be taken into account a

384

significant loss of sensitivity.

A particular

problem is the contamination by

Since this is, as is radio-

o x y g e n , absorbed as CO 2 an interference in the case of large carbon excess in the

sample

proposed

seems

inavoidable

selective sorption

(see

of

e.g.

Ref's.55,711,

819

).

Baker

tention of radiooxygen in hot cuprous oxide. Hislop and

Williams 77 ''

method with help of which all of the desired components (

n

efficiently separated.

et

al.719

by isotopic exchange and quantitative C,

13N,

re-

presented a 150)

can be

T h e y used copper metal at 600°C ( t o reduce radionitrous

o x i d e ) and Hopcalite at 650°C ( t o separate ^ C O g and C ^ O g ) to enable selective absorption of the d i f f e r e n t active components from a helium gas stream, whereby radiocarbon oxide passes the Hopcalite trap unabsorbed, pletely

retained

caught

by

and

the elemental radionitrogen

molecular

sieve.

Hopcalite

also

C^Og

passes both

serves

as

is quasi-com-

sorbants and is

an additional

purifying

agent (see also 6.1.3.2, oxidising fusion section). ωλο

Ii

Chepel et al.

ι e

used beta spectroscopy for discrimination between

C and

O,

exploiting the different maximum beta energies (960 keV and 1732 k e V , respectively;

the

activity was used as an internal photon flux monitor). An addi-

tional advantage of the method is the high counting efficiency of the detector chamber used (80-85% for ^ O ) . Other

sources

Evshanov al.719

of

chemical

et al. 7 3 2

(18F),

(21Na),

Kapitsa et

This method was also used by Pronman et al. 7 3 t ^.

interference

were

mentioned

VVasserman et a l . 7 3 ^

al.289

(indium

by

Lutz

01 c

isotopes),

(

09 Na),

Baker

et

(indium isotopes).

- Nuclear interference Excluding competing reactions by irradiating at lower bremsstrahlung

energies

is possible but can be achieved in a limited number of cases only; on the one hand, the activation threshold is somewhat lower than that of the carbon reaction (15.67 MeV compared with 18.72 MeV, r e s p e c t i v e l y ) , thus chemical i n t e r f e r ence through carbon can be excluded. The competing reactions with the highest integrated cross sections at energies below 30 MeV ( N o s . 2 and 3 in T a b . 6 . 1 - 1 1 ) are

unlikely

to

interfere,

both

"normal" matrices and fluorine, relatively hand,

high

activation

irradiating

sensitivity.

A

because

quantitative

the

low

concentration

levels

in

normally also does not i n t e r f e r e because of the

threshold

at less than

of

of the interfering

30 MeV

yield

might

assessment

entail of

the

reaction.

On the

crucial loss of interference

other

analytical

by

a f t e r 30 MeV bremsstrahlung irradiation was performed by Fusban et al.

fluorine ο on

. They

385

found a f l u o r i n e - p r o d u c e d a p p a r e n t o x y g e n concentration of 1.6% of the f l u o r i n e content. 79"ί 74"i Nordmann et a l . ion

in

sodium,

»

examined the matrix i n f l u e n c e in the o x y g e n

but,

according

to the reaction

threshold

values

determinat-

given

in

table

6 . 1 - 1 1 , this can be n e g l e c t e d at electron e n e r g i e s around 30 M e V .

Tab.6.1-11:

Nuclear reactions

by which

is

produced

Threshold Reaction

No.

Threshold

(MeV)1

No.

React ion

(MeV)1

1

16

0(γ,η)150

15.7

9

27Al(Y,2atn)150

2

19

F(y,tn)150

27.4

10

28

Si(Y,13C)150

27.5

3

20

Ne(Y,an)

20.4

11

28Si(Y,3ctn)150

39.7

4

23

Na(Y,8Li)150

33.3

12

31

Ρ(γ,1ΒΝ)150

33

5

23

Na(Y,atn)150

37.8

13

32

S(Y,170)150

28

6

24

Mg(Y, Be)

0

28.1

14

35

C1(Y,

31.8

7

24

Mg(Y,2an)150

29.7

15

36

Ar(Y,21Ne)150

27.4

8

27

Α1(γ,

33.4

16

15

N(p,n)

20 2

15

9

12

Β)

O

15

15

0

2U

F)

15

15

47.9

0

0

H a k e n out of R e f . 7 5 4 o r calculated 2taken

out of

- Other e r r o r

Since

the

Ref.858

sources

separation

purification

and

procedure

sorption

using

step are the

heat

extraction

same as

used

is v e r y

similar and

in carbon a n a l y s i s ,

the

error

c o u r c e s due t o r a d i o c h e m i s t r y a r e about t h e same in o x y g e n and c a r b o n d e t e r m i n ations.

Hence,

the r e a d e r might r e f e r to 6 . 1 . 3 . 3 ,

T h e e r r o r caused in o x y g e n cause

of

the

irradiation analysis

by

analysis

of

pre-irradiation

than

ubiquitous

treatment caesium

of or

in

the

nature of o x y g e n . sample

other

alkali

is

particular

metals.

problem

is the r e c o v e r y

of

the

other

or

impossible,

metals708»818'821·.

of

light

problematic

elements

In c r i t i c a l cases an e f f i c i e n t

difficult

Special s t o r a g e and sampling p r o c e d u r e s might

A

section.

contamination is p r o b a b l y more

determination

the

e r r o r sources

also

be r e q u i r e d in some

radiooxygen

T h e chemical y i e l d values g i v e n in T a b .

See

during

e.g.

bepost-

in

the

Pauwels725. cases818»821

a n a l y s i s of

alkali

6.1-10 r e f e r to the f o l l o w i n g

386

extraction

process:

Me2150 + H20 Me15OH + H 2 0 -

MeOH +

Me15OH

MeOH +

H2l50

However, a part of the material-inherent oxygen might be present as carbonate. This o x y g e n does not undergo the isotopic exchange process described above, as was found by Hislop et a l . ® ^ ,

Nordmann et a l . ^ ^ and others. The latter pro-

posed a separate carbonate-bound indirect oxygen analysis.

6.1.5.4

Sensitivity

The general remarks given in 6.1.3.4 also apply to o x y g e n analysis; hence it is recommended to study the named paragraph. The intrinsic sensitivities of o x y g e n analysis at d i f f e r e n t bremsstrahlung energies is given in T a b . 6 . 1 - 1 2 . According takes

to the comparatively

much

more influence

short half-life of

upon

the achievable

150

the total cooling

analytical

sensitivity

period than it

does in the analysis of the other light elements. As touched on in the preceding paragraph,

the oxygen analysis of alkali metals using the method of Lutz

fiftl (Ref.

)is somewhat problematic in terms of sensitivity.

The decay of

radio-

oxygen during

separation I70 O and its radiochemical r e c o v e r y result in an e f f e c t i v e yield (Nordmann et al. which normally is far beneath unity. T h e r e f o r e , the

sensitivity

of

radiochemical photon activation

analysis of o x y g e n ,

particularly

performed in alkali metal matrix, is limited. For instrumental oxygen analyses detection limits between 10 and 5000 nanograms have been found. Because of the above mentioned strong dependency of the analytical sensitivity

upon

various

experimental

parameters a consensus

value can

hardly be named. The average of the values reported in the literature reviewed by the authors is about one microgram. The agreement in radiochemical analysis is comparable to that in other formed radiochemically;

light

element

photon

activation

analyses

per-

detection limits from 10 to 300 nanograms were found,

quasi-peaking at 50 n g .

All in all,

the oxygen

analysis is a special problem,

independently

upon

the

analytical technique applied. In comparison to other methods, photon activation

387

analysis appears to o f f e r a high degree of reliability in the trace 009 ion level in any material .

Table

6.1-12:

Intrinsic analysis,

sensitivity

of

oxygen

detection

by

photon

concentrat-

activation

normalised to 100 microamperes mean electron beam c u r -

rent and two minutes exposure period as a function of the elec791 tron energy ( a f t e r Nordmann et al.

E e - (MeV)

sensitivity Cug O )

30

0.12

35

0.055

40

0.029

45

0.020

50

0.015

55

0.011

60

0.009

388 6.1.6

Fluorine

Among the light elements u n d e r investigation,

fluorine was studied the l e a s t .

Whilst the o t h e r elements can be analysed quasi-simultaneously, e . g . a f t e r s e paration by heat extraction and selective collection, fluorine has to be h a n d led d i f f e r e n t l y because of its peculiar chemical n a t u r e .

The only common p r o -

p e r t y - in radiochemical terms - is its being a p u r e B + -emitter and t h u s radiochemical separation is n e c e s s a r y in the most cases. 1 A F produced t h r o u g h

19

F(y, n ) 1 8 F

Τ = 109.7 m E l h = 10.44 Me V

cannot

be mobilised

by normal heat e x t r a c t i o n .

Distillation

procedures

have

been normally applied as is demonstrated in 6 . 1 . 6 . 2 . Intrinsically, and mostly in the laboratory

practice as well, the photon activation analysis of fluorine

is the most sensitive amongst all light elements. The comparatively long halflife of the product nuclide permits thorough post-irradiation s u r f a c e treatment (although s u r f a c e contamination is not of as problematic n a t u r e in fluorine a n alysis as in the determination of o t h e r light elements, e. , g . o x y g e n ) , and e f ficient

radiochemical separation.

In the a u t h o r s '

laboratory,

a limit of

de-

tection of about one nanogram was achieved u n d e r practical laboratory conditions (see R e f . 6 0 ) . As usual in light element photon activation analysis,

radiofluorine normally is

analysed by annihilation photon c o u n t i n g . The a u t h o r s could find but two messages about a n o t h e r technique applied, produced t h r o u g h 6.1.6.1

19

namely delayed neutron counting of

^N

F(y,2p)710,823.

N o n - d e s t r u c t i v e analysis

P e r h a p s more than o t h e r light elements, ference during

fluorine is subject to multiple i n t e r -

instrumental analysis a f t e r photon activation.

In several

vantageous cases an instrumental analysis is possible exploiting the

ad-

compar-

atively low activation t h r e s h o l d . T h e r e a r e v e r y few r e p o r t s about n o n - d e s t r u c t i v e photon activation determinations of fluorine; almost all of them were performed at b r e m s s t r a h l u n g energies between 12 and 18 MeV to exclude i n t e r f e r i n g a c t i v i t y . However, the sensitivity

389 is thereby limited; in advantageous cases 20 ng were reported as detection limi t , normally several hundred micrograms were found (see below). According to the literature accessible to the authors instrumental fluorine a n alysis by photon activation

was

first

proposed by Albert 7 ®·*.

He claimed

0.2

micrograms per gram as a detection limit for instrumental fluorine photon a c t i vation analysis in aluminium. Engelmann

and A l b e r t 2 ^ ' 4 5 . 7 2 6

re

p0rted

instrumental simultaneous analysis of

fluorine and carbon in high purity beryllium using 28 MeV bremsstrahlung i r r a d iation. An intrinsic sensitivity of 20 nanograms was found. They proposed i n strumental

fluorine analysis in several other high

ferent bremsstrahlung energies (Li, B e ,

purity

material using

dif-

B , Si, VV at 30 MeV; Na and Ca at 25

MeV). Andersen and c o - w o r k e r s 8 2 ' ' ·

82

® reported instrumental photon activation analysis

of F in biological material ( t e e t h ) . 12 MeV bremsstrahlung was used for a c t i v ation to avoid serious interference by chlorine. See also® 2 ®. Fluorine in organic and inorganic matrices was analysed instrumentally by Kosta and c o - w o r k e r s ® 7 , 2 ' ' 8 .

Multiple possible chemical interference

was found after

activation with 18.7 MeV bremsstrahlung of a betatron. In Ref.® 7 photon a c t i v ation analysis of fluorine is reviewed. Simultaneous instrumental photon activation in air dust

filters

analysis of fluorine and

was published by Schmitt et al.

nitrogen

. They used irradiation

with 15 MeV bremsstrahlung to exclude in particular i n t e r f e r e n c e by oxygen and carbon. Relative age determinations

of fossile materials were reported

by

Meijers787.

Nitrogen and fluorine were analysed by instrumental photon activation analysis using exposure to bremsstrahlung of about 19 MeV ( t o exclude the interfering carbon r e a c t i o n ) . The common decay function of the annihilation peak was followed for 50 hours. The components due to

and

18

F were separated and the

weight ratio between nitrogen and fluorine was used as an indicator of the r e lative age of the sample. See also 6 . 1 . 4 . 1

and827,828.

390 6.1.6.2

Radiochemical analysis

Radiochemical separations of

have been performed during fluorine analysis

by photon activation and determinations of other elements by charged particle reactions as well, e . g . oxygen analysis by proton activation using The radiochemical separation of the isotope is not at all influenced by the way of its production. Therefore many of the examples given in the following were performed with charged particle activation analysis. Radiofluorine has been separated from any matrix mostly by distillation of h y drofluoric stillation

or

fluorosüieic

acid

with

various

method for fluorine separation

radiofluorine

contents.

has been well-established

time in conventional and radioanalytical chemistry

The

di-

for a long

.

Fluorine (including radiofluorine) is evolved by dissolution of the sample in a strong,

concentrated acid, typically sulphuric or perchloric acid. After addit-

ion of some inactive fluorine compound which serves as a c a r r i e r ,

hydrofluoric

acid thus produced is either distilled as such or as fluorosüicic acid by vapour distillation.

Frequently radiofluorine has been preconcentrated before di-

stillation and t h e r e a f t e r before measurement;

typically this has been performed

by precipitation as P b ^ F C l or calcium radio fluoride. The radiation source thus prepared is then measured, normally by annihilation photon coincidence counting analysing

the

decay

curve

for

confirming

the

radiochemical

purity

of

the

applicable

for

source. In

several

cases

the

distillation

method

might

not

be readily

different reasons, e . g . volatility of any matrix component. In the following,

according to the literature accessible to the authors,

examp-

les of other techniques hitherto applied to radiofluorine separation are b r i e f ly summarised. See also T a b . 6 . 1 - 1 3 . Combined precipitation

and extraction of the matrix a f t e r dissolution in aqua

regia was performed to separate the desired radiofluorine from gallium arsenide by Bailey and Ross® 3 ^.

After addition of a fluoride c a r r i e r ,

tracted by ethyl ether,

and arsenic was precipitated subsequently

nitrate as A g 3 A s 0 4 . dily

or after

niques

After

precipitation

were also applied

filtration

with silver

radiofluorine could be either counted r e a -

with lanthanum by Bock

gallium was e x -

nitrate

et a l . ® 3 ® · 8 3 7 .

solution. Various

Extraction

tech-

precipitation

tech-

niques, either precipitating the matrix as described above or the radiofluorine

391 QOQ

were reported by Wilkniss and Born al.

ft^Q

, Nordmann and Engelmann 0 1 " and Gösset et

An amalgamation method for separation of radiofluorine from gold matrix

was reported by Wilkniss and Born""*®. Wilkniss®^ proposed to separate irradiated by

from

sea water by quasi-selective absorption in calcium sulphate followed

purification

using extraction

techniques or sublimation of ammonium

radio-

fluoride. Frequently several of the mentioned separation techniques have been combined in one procedure or have been used for p r e - or post-irradiation treatment, e . g . as preconcentration

steps

followed

by

distillation.

In Tab.6.1-13

several of

the

radiofluorine separation procedures are summarised as they have been hitherto applied,

particularly

trace l e v e l .

in

photon

activation

analysis

of

fluorine

in

the

ultra-

392 φ Ο C φ ( φη «Μ

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The p r o c e d u r e f o r calculation of the analysis r e s u l t s for both the conventional evaluation and f o r the application of an i n t e r n a l s t a n d a r d is described in p a ragraph

6 . 2 . 3 . 3 below. During long-period practical analysis work the use of

i n t e r n a l s t a n d a r d s in photon activation analysis has proven to be a useful tool to make analysis p r o c e d u r e s more convenient a n d to improve a c c u r a c y and p r e c i s ion of the obtained data (Segebade et al.®"; see also C h . 6 . 1 ) .

It should be

applied particularly in the following cases: a) Analysis sample and r e f e r e n c e material do not have the same size and s h a p e . b) They cannot be i r r a d i a t e d simultaneously. c) The irradiation geometry cannot be kept identical f o r the sample and the r e f e r e n c e material d u r i n g simultaneous irradiation,

e . g . by spontaneous mis-

function of t h e sample rotating assembly. The i n t e r n a l s t a n d a r d also c o r r e c t s for inconstancies of the i n t e g r a l counting efficiency of t h e spectrometer,

be they due to inconstant high voltage supply

of the detector o r t o counting e r r o r s caused by incorrectable dead-time losses. Following d i s a d v a n t a g e s have to be mentioned: a) The element selected to s e r v e as an i n t e r n a l s t a n d a r d cannot be a n a l y s e d . b ) In the case of nuclear i n t e r f e r e n c e (see t a b . 2) the concentration data of o t h e r components might be i n c o r r e c t . c) Neutron reactions cannot be used for analysis unless t h e r e is also an i n t e r n a l neutron flux monitor provided both in t h e sample and in t h e r e f e r e n c e material.

409

d)

T h e internal standard ment g e o m e t r y .

The

application

cannot c o r r e c t

T h i s is discussed

of

additive

deviations

f u r t h e r in

internal

Frequently

in activation for

correct

analysis,

varying

also

activating

measure-

6.2.3.4.

standards

in instrumental multielement ooQ oqn ι9Πβ by Y a g i and M a s u m o t o 0 0 0 o ™ » 1 ' " 0 .

photon activation a n a l y s i s was also r e p o r t e d

to

due to inconstant

external

flux

flux

densities.

monitors

Generally

have

been

discs,

used

sheets

or

wires are used which match with the sample g e o m e t r y . In photon activation a n a lysis

this

has

Feimers et

In

this

been

done

in

the a n a l y s i s

of

ancient

Noble

Metal

coinage

(see

distance

from

al.884>1180.

case

the

samples

were

located

at a c o m p a r a t i v e l y

large

the b r e m s s t r a h l u n g c o n v e r t e r namely about 50 cm and hence the photon field was f a i r l y homogeneous. material ever, an the

discs,

C o p p e r discs with the shape of the coins and the r e f e r e n c e

respectively,

were

samples are i r r a d i a t e d

external

flux monitor

sample and

situation.

All in all,

compared

correct

irradiation

In the normal case,

with

Therefore,

other

geometry

it would

instrumental

not yield any

radiometric

in photon activation

analysis

since

the

incident

radiation

is

analysis

methods,

narrow beam

(see chapter 3),

cally around

the source with r e s p e c t both to the e n e r g y

whereas neutron radiation

in

a

of

the

proble-

than in neutron

concentrated

of

improvement

a n a l y s i s is of medium

matic n a t u r e ; it has to be handled more c o n s e r v a t i v e l y ion

how-

would bear the d a n g e r of inhomogeneous activation

the monitor.

the initial

used as monitors.

at a distance of a few centimeters and the use of

activat-

comparatively

is d i s t r i b u t e d

isotropi-

spectrum and the flux

density.

On

the o t h e r

sis

or

X-ray

problem

than

penetration ever,

hand,

in o t h e r t e c h n i q u e s like c h a r g e d

fluorescence in photon

depth

analysis

activation

the

irradiation

analysis.

geometry

is

much

analymore

T h i s is due to the e x t r e m e l y

of s o f t X - r a y s and c h a r g e d

in any of these methods,

particle activation

particles in most materials.

the use of internal s t a n d a r d s will most

yield maximum a c c u r a c y and precision of the obtained analytical

data.

a

small How-

probably

410

6.2.3

General analytical

procedure

At t h i s p o i n t , t h e l a b o r a t o r y p r o c e d u r e g e n e r a l l y used in photon a c t i v a t i o n a l y s i s is d e s c r i b e d .

ken a s a model; p r o c e d u r e s followed in o t h e r photon a c t i v a t i o n a n a l y s i s atories, below.

if

essentially

different,

D i f f e r e n c e s to t h e

niques are emphasised. ual c a s e s

are

an-

T h e p r o c e d u r e as a p p l i e d in t h e a u t h o r s ' l a b o r a t o r y is t a -

given;

are

procedures

described used

in

the

labor-

application

in o t h e r a c t i v a t i o n

section

analysis

tech-

No detailed d e s c r i p t i o n s of p r o c e d u r e s used in i n d i v i d if t h e y

are

necessary

for

better

understanding

of

the

p r o b l e m , t h e y a r e summarised in t h e c o n c e r n i n g p a r a g r a p h s in 6 . 2 . 4 . 6.2.3.1

Sample p r e p a r a t i o n , t r a n s f e r a n d

irradiation

As mentioned in c h a p t e r 3, t h e q u a s i - f r e e choice of t h e i r r a d i a t i o n

volume e n a -

bles t h e photon a c t i v a t i o n a n a l y s t to p e r f o r m n o n - d e s t r u c t i v e a n a l y s e s of l a r g e samples e.g.

more

often

than

e.g.

in

neutron

activation

analysis.

Large

objects,

machine p a r t s o r l a r g e volume liquid or gas c o n t a i n m e n t s can be placed in

f r o n t of t h e c o n v e r t e r

target.

t h e special d i s t r i b u t i o n

of t h e photon r a d i a t i o n ,

terested

Of c o u r s e t h e r e a r e

s e v e r a l limitations d u e to

b u t in many c a s e s one is i n -

to a n a l y s e a small a r e a within a l a r g e object w i t h o u t being allowed to

take a sample.

Positioning

t h e a r e a of i n t e r e s t of t h e object in f r o n t of

the

b r e m s s t r a h l u n g s o u r c e one can easily a c t i v a t e t h i s spot a n d no damage o c c u r s to the object.

However, quired,

in t h e most c a s e s an a n a l y s i s of c o m p a r a t i v e l y typically

pieces generally

some

tens

of

milligrams.

If

samples

lie

small samples is

re-

b e f o r e as

compact

no special p r e c a u t i o n s a g a i n s t s u r f a c e c o n t a m i n a t i o n s

h a v e to

be u n d e r t a k e n s i n c e t h e y can easily be removed a f t e r a c t i v a t i o n . T h i s is e s p e c ially t r u e in t h e c a s e of metals to be a n a l y s e d . M e a s u r e s f o r s u r f a c e c o n t a m i n ations

removal a r e e x t e n s i v e l y

light elements a n a l y s i s .

described and discussed

T h e contamination

in c h a p t e r 6 . 1 on

the

problem in t h e a n a l y s i s of t h e h e a v -

i e r elements g e n e r a l l y is not as s e r i o u s ; t h e most f r e q u e n t c o n t a m i n a n t s

norm-

ally a r e a t m o p h e r i c o x y g e n , n i t r o g e n a n d c a r b o n (as C 0 2 ) · C o n t a m i n a t i o n s d u e to atmopheric

particles

normally

do not o c c u r

in a c t i v a t i o n a n a l y s i s to a s i g n i f i -

c a n t e x t e n t s i n c e t h e a t m o s p h e r e in a r a d i o c h e m i c a l l a b o r a t o r y is p u r i f i e d from d u s t by air c o n d i t i o n i n g . T h e main s o u r c e of contamination

by h e a v i e r e l e m e n t s

is d u e to a b r a s i o n of t h e tools used in t h e d i f f e r e n t p h a s e s of sample

prepar-

ation

powder-

ed

(storage vessels,

materials

to

be

mills, tools for b a t c h i n g e t c . ) .

analysed

a

post-irradiation

In t h e c a s e of

purification

normally

p o s s i b l e . T h e r e f o r e , it is of use to r u n b l a n k s if a v a i l a b l e . H o w e v e r ,

is

the

not

411 problem of contamination due to the packaging material which is in cdose contact

with

the

sample d u r i n g irradiation

obviously is not a too serious

one.

T r a c e r experiments were carried out in the a u t h o r s ' laboratory to investigate the component exchange behaviour between the sample and the packaging material. According to the r e s u l t s ,

no significant contamination by o r d i n a r y

household

aluminium foil which generally has been used for sample wrapping could be d e t e c t e d . In a few cases, loss of elements to be analysed due to recoil into the wrapping material was r e p o r t e d in the l i t e r a t u r e (see 6.1 and 6 . 2 . 3 . 4 ) . Similarly, t h e contamination of liquid samples by the material of the container (typically PYREX glass) was r e s t r i c t e d to v e r y small t r a c e s of sodium, probably due to isotopic exchange in the glass s u r f a c e . as noted above,

In photon activation analysis,

the most suitable material for packaging of solid samples and

t r a n s p o r t a t i o n to the irradiation position is aluminium since, on the one hand, it

does

not

undergo

(see c h a p t e r short-lived

a photonuclear

5), and,

reaction

on the other hand,

nuclides (2®A1,

27

with

significant

activity

yield

the n e u t r o n reactions yield either

Mg) o r moderate activities ( 2 4 N a ) . The samples

a r e wrapped in aluminium foil and packed in aluminium r a b b i t s f o r t r a n s p o r t a t ion in the pneumatic t u b e system (see c h a p t e r 3 ) . In the case of volatile components to be analysed ( e . g . Hg) samples have to be irradiated in sealed high p u r i t y q u a r t z vials or especially p r e t r e a t e d to avoid losses d u r i n g

irradiation.

A method

for prevention o r at least reduction of

mercury losses d u r i n g b r e m s s t r a h l u n g e x p o s u r e is described in the application section below ( 6 . 2 . 4 ) . Although usually t h e sample r a b b i t s a r e air-cooled d u r ing irradiation,

one has to take into account a considerable heating of the

sample d u r i n g long-time ( g r e a t e r than 10 mintues) e x p o s u r e . Moreover, damage may also occur to t h e samples by the incident radiation i t s e l f . This gains importance especially if either organic or liquid matrices have to be irradiated a t s h o r t ( u p t o 5cm) d i s t a n c e s from t h e b r e m s s t r a h l u n g c o n v e r t e r . During p r a c tical work it was found that in the case of s h o r t period (less than 10 minutes) irradiations

organic material like plant

much from radiation

damage,

or tissue matrix does not s u f f e r too

nor do water samples if they are irradiated in

glass vials which a r e wrapped in aluminium foil. If these materials are i r r a d iated f o r longer periods at small distance from the t a r g e t , damage due to both heat and radiation becomes significant; in the case of organic matter the material s t r u c t u r e is partly destroyed and volatile components a r e set f r e e . Water will be partly decomposed and evaporised. A cooling of the sample d u r i n g i r r a d iation could r e d u c e the evaporation of volatile components but not avoid iation damage.

rad-

412

There is not much one can do to prevent damage of organic material; one has to select,

with respect

to the required analysis sensitivity,

the shortest

possi-

ble bremsstrahlung exposure period. For quantitative evaluation it is then necessary to determine the sample mass ahead of the irradiation to avoid errors due to uncontrolled losses of components. In the case of water samples it is useful to remove the irradiation position to 10-20 cm from the converter target and irradiate a larger volume. Thereby, heat and radiation damage are reduced and, by convection,

heat is distributed over a large sample volume and hence

rendered less harmful. Normally, the sample volume is restricted to a maximum of

about

10 milliliters

in the

pneumatic

tube

rabbit.

For

more information

about losses of sample components - particularly during sample preparation and irradiation - the reader might refer to 8 ® 2-8 ® 4 and to paragraph 6.2.4.8, single element studies. Larger vessels (100 ml maximum) can be exposed to the bremsstrahlung radiation using the rotating irradiation facility. But then, as explained above, one has to take into account significant flux gradients. liquids,

Yet larger volumes,

especially

should be irradiated in a cylindrical container whose axis coincides

with the bremsstrahlung radiation axis; about 1200 ml proved optimal for trace element determinations in water samples (see 6.2.4); yet larger volumes can be activated if ry,

required;

using the irradiation facility in the authors'

up to seven liters have been irradiated,

laborato-

but then a considerably

small

fraction of the total sample volume is activated by the bremsstrahlung; in the case of such large volumes irradiated the exploitation of the photoneutrons as activating particles gain importance. Therefore, in any case, one has to carefully optimise the total sample mass or volume, respectively,

according to the

analyst's requirements; see also Ch.3. Exposure periods have to be selected according to the half-lives of the reaction products under consideration and to the required analytical

sensitivity,

respectively; in the authors' laboratory a maximum of five hours has proven suitable for multitrace analysis of microgram amounts of components to be determined.

The exposure times in the different application cases are given in

the application section below. Sometimes, more than one exposure has been performed for convenient measurement of activation products with greatly different half-lives. Moreover, different activation

frequently several exposures have been performed using energies

to obtain a quasi-selective

activation

exploiting

the difference in threshold energies. However, this is of questionable value if routine analyses of large series of samples have to be carried out. In this case it is of advantage to irradiate with maximum energy and to account for

413

first

order

interferences

with

correction

calculations.

Although

thereby

integral uncertainty of the results is somewhat enhanced these correction

the rou-

tines are recommended to keep a reasonable time-schedule of the analysis task. T o a certain extent,

this also applies to the product activity measurement as

is discussed in the next paragraph.

6.2.3.2 Basically,

Preparation for counting and photon spectroscopy the

preparation

of

the irradiated sample f o r counting is done

fol-

lowing the same procedures as usual in neutron activation analysis. However, in the authors'

laboratory it has proven useful in many cases if solid

samples are irradiated,

powdered

to mix the sample with cellulose powder and press it to

a pellet of 15 to 20 mm diameter and less than 1 mm thickness. This geometry is particularly useful if both gamma spectroscopy and low energy photon spectroscopy are required

(see 2 . 5 ) ;

self-absorption of softer photon radiation to be

evaluated for analysis is thus reduced. Liquid samples, if analysed purely i n trumentally, have been filled into vessels shown in F i g . 6 . 2 . 1 .

mi - active Ge

- Detector

_liquid_

Housing

container

-

(600

ml)

Π5

F i g . 6.2.1: Counting setup for radioactive liquid samples

-

414 Using t h e s e containments f o r counting, the detector c r y s t a l is partly s u r r o u n d ed by the sample. T h e r e b y , considerable counting efficiency is gained compared with

conventional

counting

vessels positioned

in f r o n t of the

detector.

For

counting it is of a d v a n t a g e to establish conditions in which the dead-time of the electronic equipment does not exceed about 10%. This can be realised by a p r o p e r measurement geometry o r by a sufficiently long cooling period. By e x c e s sively high count r a t e s ,

the resolution capability of the spectrometer is s i g -

nificantly

chapter

reduced

(see

4).

Moreover,

laboratory

experiments

have

clearly indicated t h a t a dead-time of more than 10% r e g i s t e r e d by the electronic equipment

implies

considerable

dead-time

losses

within the

spectrometer

which cannot be controlled and hence not be accounted f o r by live time counting (see C h . 4 ) . Nowadays,

electronic equipment is available which provides fairly good gamma-

r a y peak s h a p e s and spectral resolution in the case of high input pulse r a t e s ; additionally, as mentioned in c h a p t e r 4, new ways have been found concerning pile-up

management

equipment.

and account

Nevertheless,

spectrometer,

for dead

time losses

the mentioned uncontrolled

with help of any hardware,

due to the

electronic

pulse rate losses in the

cannot be managed satisfactorily as

y e t , except - to a certain extent - by the use of an i n t e r n a l s t a n d a r d , a s e x plained in 6 . 2 . 2 . One disadvantage of photon activation analysis if short-lived product nuclides have to be measured is the large background activity of

15

0

due to the oxygen c o n t e n t s which is mostly considerably h i g h . Although 511 keV annihilation

radiation exclusively is produced by oxygen,

the detectability of

o t h e r components with say minutes of half lives is severely hampered by the dead-time losses due to the integral input pulse rate and also in the case of s o f t e r photon radiation to be measured, by s e v e r e degradation of the s i g n a l - t o b a c k g r o u n d ratio due to the Compton continuum, effected by annihilation iation.

This is,

to

analysed.

be

usually 28

of course,

a r e evaluated

Si ( A1,

29

especially t r u e in the case of low

Therefore,

A1), Κ (

38

short-lived

activities

after

concentrations

photon

activation

for analysis of major or minor components only, K ) , Fe (

53

rad-

e.g.

F e ) . In o r d e r to r e d u c e the mentioned i n t e r f e r -

ence, one should use a multiple step p r o c e d u r e beginning with a s h o r t period e x p o s u r e , cooling and measurement followed by either a longtime reactivation of the same sample o r of a n o t h e r batch of the material and one o r more cooling and counting p e r i o d s . However, in the case of large series of samples to be a n a l y s ed one should

generally s t r i v e for a minimum of irradiation and

measurement

s t e p s d u r i n g analysis, as noted above. In the ease of say one single activation and one measurement i n t e r f e r e n c e s of various t y p e s have to be taken into a c c o u n t . The management of t h e s e i n t e r f e r e n c e s d u r i n g analysis evaluation p r o c e -

415

dure is described in detail in paragraph 6.2.3.3. As explained in chapter 4, in o r d e r to achieve

maximum resolution

capability of the spectrometer,

it is r e -

commended to collect the spectra in as many channels of the multichannel analyser memory as possible.

However, it is recommendable to save a certain partit-

ion of the total memory for intermediate fast spectrum storage after counting. Moreover, the total storage area might be quickly consumed if more than one d e tector are connected to one multichannel analyser.

A l l in all, sis,

during

practical instrumental multielement

photon activation

analy-

2048 channels have proven to be a suitable storage size and meet the r e -

quirements

of

photon

spectroscopy

quasi-optimally,

although in this case the

maximum achievable e n e r g y resolution of modern semiconductor detectors cannot be exploited; an average gamma-ray line then contains 4 to 5 channels at about 2200 keV total e n e r g y range (see also C h . 4 ) .

6.2.3.3

Data handling

At this point, no lengthy descriptions of spectrum processing and data evaluation computer programs are given but rather the basic principles of data handling in photon activation analysis. Although,

as already noted, storage memory

size is not the primary problem in modern multichannel analysers,

space is lim-

ited and especially if large series of samples has to be analysed,

spectra have

to be dumped quickly on any data carrier which enables subsequent data processing by computer. Data frequently have been stored on punched paper tapes, but nowadays mostly more convenient carriers are in use, e . g . magnetic tape or magnetic disc. Although modern multichannel analysers, as described in chapter 4, usually

are

equipped

data processing

with

microprocessors

by computer is preferable.

and

associated

Small,

software,

easy-to-run

external

computers are

mostly used f o r spectra processing. Nowadays, a large variety of these machines are

available,

so that one can select a suitable unit

which ideally

meets the

individual requirements. Moreover, many manufacturers supply the complete gamma measurement software for relatively moderate prices. The first step of multi-component identification.

spectrum evaluation is the peak search and

It depends upon each analyst's personal philosophy if an auto-

matic peak search program is used or if the qualitative evaluation is performed interactively. a fully

In

automatic

the

daily

peak

practice

search

it

program

has been shown that the reliability decreases

with

the complexity

of

of the

spectrum. Moreover, these programs are mostly severely hampered if peaks are to be detected which are located in the close neighbourhood of either huge Compton

416 e d g e s o r o t h e r l a r g e r p e a k s . Since especially in photon activation analysis one has to be aware of complex s p e c t r a emitted by activated multi-component samples it is recommended to perform qualitative analysis interactively accompanied by visual control.

Fully automatic programs should be used in the case of large

series of routine analyses a f t e r having ascertained that t h e peak search r o u t i ne o p e r a t e s reliably and the integration works precisely in any case. It also d e p e n d s upon t h e individual a n a l y s t ' s philosophy in which way t h e net peak area i s determined. Some d e s c r i b e t h e peak b a c k g r o u n d by higher o r d e r f u n c t i o n , but an

extended

investigation

yielded

no significant d i f f e r e n c e between

the

net

peak a r e a s obtained by linear o r higher o r d e r b a c k g r o u n d subtraction in the case of semiconductor s p e c t r a to be processed®^®'

In photon activation a n -

alysis, the peak assignment can easily be performed with help of photon e n e r g y compilations

( e . g . o r

libraries i n t e g r a t e d

the tables in C h . 5 of t h i s book or with nuclide

in the microprocessor

software of the multichannel

ana-

l y s e r a s explained in c h a p t e r 4. Quantitative analysis evaluation As already noted, element concentration data a r e obtained by activity comparison of t h e analysis sample with a r e f e r e n c e material. Going out from equation 1.17 in c h a p t e r 1.3 the relation between the induced activity and the mass of the element to be determined is:

(1.17)

which means that t h e induced activity s t a n d s in linear relationship to the mass of the i r r a d i a t e d element.

Simultaneous irradiation of the analysis sample and

the r e f e r e n c e material assumed, the ratio between the activities of the element to be analysed in both materials immediately a f t e r irradiation, is:

As(Tj)

=

Α„(Τ;)

m,'s m,R

S = analysed sample R = r e f e r e n c e material

(6.1)

417

Since one generally does not determine absolute element masses but r a t h e r component concentrations, m is t h u s replaced:

C = concentration of t h e component to be analysed m = mass of the determined component Μ = total mass of the sample The concentration of t h e desired element in t h e sample is then e x p r e s s e d b y :

Cc =

As explained

in 5.3.1,

5 * Ms'AR(Ti)

the activity is determined

(6.2)

by photopeak

integration.

Using equation 5.4 in p a r a g r a p h 5 . 3 . 1 one obtaines t h e relationship between the net photopeak i n t e g r a l and the activity:

e-iTD I = A(Tj) • Θ • η •—-—·

(1 — c~lTc)

(6.3)

where I is the photopeak i n t e g r a l . In the case of each individual component to be determined, the photopeak emission probability

(Θ),

the spectrometer counting efficiency (η) and the decay

constant of the product nuclide (λ) a r e identical f o r both the analysed sample and the r e f e r e n c e material. Hence, the activity ratio of both can be e x p r e s s e d as:

A s (Tj) _ I s A r (Tj) ~

e~·* ' e^

Tp R

1-e"'t

Tc R

Td s

1-e-A

Tc s

418 Insertion into equation 6.2 yields:

CR • M r · I s

cs =

e~' l ' ( T D · R _ T D · s , — e _ A ' ( T D l-e

M s • IR

- 1

'

1

H ~ T D S + T c R)

(6.5)

«

Cg = desired component concentration in the analytical sample Cg = known component concentration in the reference material ^S/R 's/R

=

sample/reference material

mass

= ne*

photopeak area of the product nuclide in the spectrum

of the sample/reference material λ = decay constant of the product nuclide Tq = decay period T g = counting period Remember: simultaneous irradiation of the sample and the reference material is still assumed and no internal flux monitor is used. Let us consider now the application of an internal standard which is particularly useful in the case of non-simultaneous irradiation of the sample and the reference material, respectively. However, in this case the same electron energy must be assured in both irradiation cycles. The net peak areas of both the analysed nuclide in the sample and the reference material, respectively, and of the nuclide regarded in the internal standard are calculated using E q ' s .

1.17

and 6 . 3 . In combinig the resulting four eqations for the net peak area, the a c tivating

photon

flux

densities

in both

irradiations

as

well as the

effective

cross sections of the considered nuclear reactions are eliminated. The desired concentration value of the analysed component can then be calculated from the following expression:

Cs =

Cr * Is ' Ii.r ' Q , s

1_

e

- Af · TD, : l - e - V T , . :

Λ~

Ir ' Ii,s ' Q,R ~Al T c R

e

1

(Explanations see next page)

Μ'

Td, ι ' Ϊ — e - -I - Τ,,,

,-Λ-Ti.s

1 — e~A'TcR

»- λ •

(Td. r - Td, s)

(6.6)

419 In the case of simultaneous irradiation of the sample and the reference material E q . 6 . 6 simplifies to:

, - M c , s

Cs =

. " λι • T o , R

Ir ' Il.S ' C|,R

I

Q — λι • T c , R

j

g - Λ - T c ,

e

- A

( T

D

, R - T

D

, s )

(

6 > 7

)

R

Index S = analysis sample data Index R = reference material data C = concentration of the element to be analysed I = photopeak integral of the product nuclide I j = photopeak integral of the internal flux monitor Cj = concentration of the internal flux monitor λ = decay constant of the product nuclide of the element to be analysed = decay constant of the internal standard product nuclide T j = period of bremsstrahlung exposure T D = decay period T Q = counting period Using this expression,

spectroscopy data can easily be computed as fast and

conveniently as the available h a r d - and software allow. 6.2.3.4

Error sources

In this paragraph, only those e r r o r sources are discussed which are typical for photon activation analysis;

knowledge of the reader about accurate

sampling,

precautions against contamination and other general analytical laboratory

tech-

niques are assumed. Furthermore, as explained in chapter 4, e r r o r s due to malfunctions of the electronic system of the spectrometer nowadays are fairly unlikely to occur.

Inconstancies occurring

by any mischance mostly can be a c -

counted for by using an internal standard or a reference pulser as demonstrated in chapter 4. More information about various e r r o r sources in photon activation analysis can be found in 6 . 1 . - Irradiation geometry and bremsstrahlung energy As already noted in C h ' s . 3, 6.1 and 6 . 2 . 2 the irradiation geometry is somewhat delicate due to the incident photon beam geometry. B u t , as explained above,

420

e r r o r s due to the sharp flux gradient can be avoided by using an internal standard.

However,

excessively different locations of the analysis sample and the

reference material in the photon beam can cause e r r o r s due to the e n e r g y g r a d ient which,

although

slight

compared with the flux gradient

(see

Fig.6.2.2),

cannot be accounted for by the internal monitor.

Fig.

6.2.2:

Schematic

representation

of

the

flux

gradient

and

the

effective

gradient of the activating photon energy perpendicular to the beam axis at a distance from the bremsstrahlung converter of 5 cm

This is particularly

true in the case of analysis reactions with comparatively

high threshold energies, e . g .

( γ , 2 η ) or ( γ , a n ) . F i g . 6 . 2 . 3 shows that at an in-

cident energy of about 30 MeV a moderate electron e n e r g y shift would not have significant e f f e c t

upon the activity yield of the internal flux monitor

whereas

the yield of the analytical reaction would be altered significantly.

However,

reactions other than ( γ , η ) are used for analysis evaluation in v e r y

few cases only, but these reactions sometimes cause i n t e r f e r e n c e .

Therefore,

421

Fig. 6 . 2 . 3 : Schematic typical yield c u r v e s for a ( γ , η ) and a (γ, η ρ) -reaction

uncontrolled

photon

energy

electron e n e r g y output t h e irradiation

position,

shifts,

be they caused

by inconstancies of

the

of the accelerator or by mislocation of the sample in might lead to incorrect

values

within

the

interfer-

ence calculation process which is described below. To a certain e x t e n t ,

errors

due to the irradiation geometry can be avoided by rotating the sample in the beam. See also 6 . 1 . - Matrix absorption Another source of e r r o r in the irradiation phase is due to the absorption of the incident b r e m s s t r a h l u n g beam within the sample. In t h e case of thick sample l a y e r s of high

density

material irradiated

the flux gradient along the beam

axis due to the high attenuation might become s i g n i f i c a n t , and, in the case of largely d i f f e r e n t r e f e r e n c e material matrix, lead to uncomparable activation of b o t h . This e r r o r is much more likely in thermal neutron activation analysis due to the l a r g e d i f f e r e n c e s in the neutron absorption c r o s s section of the ele-

422 merits,

but in extreme cases - e . g .

if lead or gold matrix is irradiated - it

might gain significance also in photon activation analysis (see e. g. Reimers et al.®® 4 ).

In this case correction steps have to be inserted into the evaluation 717 ).

process (Lutz et al.

- Damage by radiation and heat Yet another e r r o r source in the irradiation step is due to the chemical effects of the incident

radiation

upon the sample material.

Moreover,

one has to be

aware of significant heating of the sample in the irradiation position close to the bremsstrahlung converter, as was already explained in the preceding paragraph. This problem is common to all activation analysis methods and it becomes expecially significant if organic matrix is activated·'··'·^·'. As touched on above, a

special case in instrumental photon activation

analysis as in almost

every

instrumental analysis method is the analysis of mercury because of the volatility of most of its compounds. In this case sealed vials have to be used for i r radiation and measurement or the element has to be t r a n s f e r r e d into a compound which is able to stand irradiation and heat without being evaporated.

Special

procedures have been developed to " t r a p " the mercury, e . g . with sulphur compounds,

during activation and thereby transform it into relatively stable and

resistant

HgS

(see

e.g.

Raghi-Atri and Segebade®®®;

see also

6.2.4.3

and

6 . 2 . 4 . 8 below). As also briefly mentioned in the preceeding paragraph,

losses of several ele-

ments due to recoil from the sample into the wrapping material have been

re-

ported49. Generally,

before irradiating any material its resistance against radiation and

heat must be assessed,

not only regarding the accuracy of the analytical r e -

sults but also for radiation protection reasons; being volatilised during irradiation,

e.g.

in the case of some elements

mercury or iodine,

contamination

by

their product nuclides of the working area might o c c u r . T h e r e b y , both the legal radiation

protection

requirements

are

affected

and

also spectroscopic

inter-

ference by contamination of any samples to be measured may falsify the accurate data. - Integral sample activity and composition of the sample The first source of e r r o r in the spectroscopy step is excessive integral count rate of the sample due to the matrix activity (see C h . 4 ) , especially if the

423 analytical sample and the reference

material have essentially different

matrix

compositions. As already mentioned, differences in the signaKto-background r a tio between

both

may falsify

the analytical r e s u l t s .

Electronically

incorrect-

able dead time losses within the spectrometer can be accounted for by using an internal standard,

as mentioned above, but since the deviation due to bad s i g -

nat-to-background ratio is contingent upon the signal energy and the internal standard generally is represented by only one photon e n e r g y , it cannot correct for this source of e r r o r .

Hence the analyst

has to care for similar integral

activities of the sample and the reference material,

preferably by selecting a

reference material with similar matrix composition as already noted. - Measurement geometry The counting efficiency is strongly dependent on sample/detector geometry, p a r ticularly at low (up to 500 keV) photon energies and at short distances between the measured sample and the detector. Therefore, the counting geometry has to be kept as similar as possible for the analysis sample and the reference material,

especially if they are,

as is usually done,

measured very closely to the

detector; The internal standard cannot account for deviations due to changes in the absolute counting efficiency. Experiments have shown that at distances of more than 4 cm from the detector housing the sample geometry is not crucial if an internal standard is used (see F i g . 6 . 2 . 4 ) ;

If soft photon radiation is to be

measured, however, differences in the measurement geometry should be avoided

cm Fig. 6 . 2 . 4 : Ratio between the net area of the analysed peak and the net area of the internal standard line as a function of the distance sample-det e c t o r entrance window

424

-

Self-absorption

Errors

due to s e l f - a b s o r p t i o n

signficant

spectroscopy.

In t h e a u t h o r s '

into thin pellets reference

material

use of an

with

However,

t h e sample matrix is only

similar

matrix

powdered samples mostly a r e

standard

photon pressed

in e x t r e m e c a s e s , e . g . if t h e r e is no available,

l o s s e s have to be performed

internal

they a r e , of c o u r s e , - Spectral

r a y s within

laboratory

(see 6 . 2 . 3 . 1 ) .

the self-absorption The

of photon

in t h e c a s e of high d e n s i t y matrix material or in low e n e r g y

correction

calculations

( R e i m e r s et a l .

cannot correct

1180

,

Lutz

t h e s e count r a t e l o s s e s

s t r o n g l y d e p e n d e n t upon t h e a b s o r b e d

of 714

).

since

energy.

interference

One can distinguish between t h r e e kinds of i n t e r f e r e n c e when using gamma s p e c t r o s c o p y and low e n e r g y photon 1 - Competing

reactions

same activation 2

-

the

spectral

spectroscopy.

(first order interference),

product from d i f f e r e n t t a r g e t interference

of

radiation

of t h e same activation

energies

and Jervis®®'' compiled

of

(peak

different

of t h e

activation

overlap);

product by s e c o n d a r y

lides by produced by two or more t a r g e t Chattopadhyay

t h e production

nuclides;

p r o d u c t s due to limited s p e c t r o m e t e r resolution 3 - t h e production

i.e.

decay of

nuc-

elements.

some p o s s i b i l i t e s

to r e d u c e t h e s e

inter-

f e r e n c e s to an inavoidable minimum: In

t h e c a s e of competing

^5Μη(γ,η)54Μη

(see

photonuclear

below)

the

bremsstrahlung

t h r e s h o l d e n e r g y of the i n t e r f e r i n g 56

reactions

reaction

such

as

energy

F e ( Y , n p) 5 4 P1n can

be

set

below

and the

(in this example £ ^ = 2 0 . 9 MeV for

Fe(Y,np)54Mn.

In t h e c a s e of o v e r l a p p i n g gamma-ray l i n e s , s e v e r a l p r o c e d u r e s were s u g g e s t e d . If

the

decay

interference to

interfering If

neither

negligible activity radiation

is

due

activity

to a

before

is a c c o u n t e d energy

short-lived

nor

nuclide,

measurement,

for a n a l y s i n g half-life

or

it the

is

f e r e n t gamma-ray line must be used for a n a l y s i s .

allowed

contribution

t h e combined

difference

either decay

of

to the

functions.

allow a s e p a r a t i o n ,

a

dif-

425

The third type of i n t e r f e r e n c e (not mentioned by Chattopadhyay and J e r v i s ) i s caused by secondary decay into a common product nuclide, e . g . 48

Ca(Y,n,E>~) 4 7 Sc.

This i n t e r f e r e n c e f r e q u e n t l y can be avoided

example by analysis of titanium using

49

48

Τϊ(γ,p)4^Sc,

(in the above

T i ( Y , p ) 4 8 S c ) or neglected due to poor

activity yield. The various t y p e s of i n t e r f e r e n c e o c c u r r i n g in photon activation analysis,

and

methods to avoid or r e d u c e them, were r e p o r t e d by many a u t h o r s (see application section below). However, most of the proposed methods a r e r a t h e r time-consuming and r e q u i r e excessive working e f f o r t . Hence t h e y can hardly be used in routine multielement analysis. In the a u t h o r s ' laboratory, considerable e f f o r t has been spent on the i n t e r f e r e n c e problem in photon activation analysis, and correction p r o c e d u r e s have been developed which a r e i n t e g r a t e d in the s p e c t r a processing and data evaluation computer programs (Segebade et al. 1 - I n t e r f e r e n c e by competing reactions As was shown in c h a p t e r 5, f r e q u e n t l y common reaction p r o d u c t s a r e formed by d i f f e r e n t elements d u r i n g activation with high e n e r g y radiation t h r o u g h competing

reactions.

The

probability

of

their

occurance

and

also

their

activity

yields increase with t h e incident radiation e n e r g y .

55

M n ( y , n)

54

Mn

56

54

F e (y, n p )

59

C o (y, a n ) 5 4 M n

Mn

If, as mentioned above, the electron e n e r g y is set below 21 MeV the 835 keV peak of "*4Mn would be exclusively due t o manganese a s a t a r g e t element, but one would have to take into account a serious decrease of the i n t e g r a l

analysis

s e n s i t i v i t y . Using a n o t h e r reaction of the competing element a s a r e f e r e n c e t h e contribution of the i n t e r f e r e n c e to the common product activity can be calcula t e d . This method can be used u n d e r the following conditions: (1) The activity yield ratio of the i n t e r f e r i n g and the r e f e r e n c e reaction must be known. Since the activities a r e determined in terms of photopeak i n t e g r a l s , absolute

emission

probabilities of all photon lines involved and the

(2)

both the detector

efficiency function must be known. T h e s e conditions fulfilled, the i n t e r f e r e n c e can be calculated. The i n t e r f e r e n c e case be the following:

426

Analytical reaction:

5 5 Mn(y, 5 6 Fe

( y , np) 5 4 , Mn

5 4 Fe

(y, np)52Mn

Interfering reaction: Reference reaction:

n)54Mn

E„ = 835 keV E y = 744 keV

Going out from equation 5.7 in paragraph 5.3.1

Ι = Α(Τ,)·θ·ιτ^—-(l-e-*·^)

the

peak

area

ratio

of

the

interfering

*1γ, inl

^Inl (T|)

line

and

the

(5.7)

reference

line

can

be

calculated:

I|nt _

Ιηι

Aref

e

T°

1

e

A '"'

Tc

where int = interfering line data ref = reference line data As explained in paragraph 5.3.1, from the single element activations, the ratio between the specific activities ( N ) of the product nuclides and the nickel monitor were calculated by:

N

= a

" ( T ' = l h ) aNi(Ti=lh)

a e j ( T ) = activity of product nuclide,

(5.1)

divided by mass of element,

after 1 hour irradiation under standard conditions. Since the interference and the reference reaction occur in the same element, the ratio between the N-values of both reaction can be expressed in terms of the activities:

Nint

A i n t (Tj = 1 h)

Nref

Α „ Γ ( η = 11ι)

(6.9)

427 Conversion

of the activities

for the actual analysis irradiation

time,

and i n -

sertion into equation 6.8 yields:

τ lm

N. Pt . μ 1 ρ-Ίΐηΐ·τ 0 _ J int ^y, inl "y, int Aref c r ~ " ' Nref ' 0 y , r e f ' ' ' ^ ^ ' ]

g~

' Tc

J_e-A„r'Tc

J _ g - Arer • Τ J_g-^lnl-T

j

(6.10)

g - Ai„t ' Tj

J_g.i,er-Ti

T j = actual exposure period In the most cases the irradiation

time is much shorter than the half-lives of

product nuclides. Then equation 6 . 1 0 can be simplified to:

I

Ν-int θ t, int Π Aref eρ~Ίΐηΐ'Τ 0 14 _ e„-Alnl Tc _ I Vy, int Χ int — 'ref ' x τ ' ' ' — ' ~π ' ϊ N r.r T y, ref W Ainl e ' ° l _ e " ^ T c

(6· I D

The correction factor

γ

_ 1

N int ' 0 y.in' " ^r·'"' N r e f · 0y, r e f ' 'iy.ref

was calculated for the most frequently occurring interfering

(6.12)

reactions and is

listed in table 6 . 2 - 2 . The corrected analysis peak area is calculated b y :

I corr = T meas —I*ref V'1 · -^i i !

where

'corr 'meas

= =

g-»nf Td

j _ g ~ A r c f T c · j _ g - A i n: i ΐ' · j

corrected analysis photopeak integral measure(

l gross photopeak integral

= correction factor (see e q . 6 . 1 2 )

g *=r c fψ' l C6.13)

428

α c0

ι-Η I ω ρο

fr-

c ο •ρ*

t5 φ £-, h ο ο

ε ο '·*-» U φ

U ο

υ

Ό C

Ν +

1-Η

1-Η

1-Η

σ>

ω 00 co

ω

ω

»-H I ω

1-Η

Ο

ω CO CO

ω

ο

ω 00 CO

CM I ω rH Ο

rH

ω CM CO

Ο)

CM

ι-Η

1-Η

CO

00

co

1-Η

CM

1-Η

ι—Ι

/-S i-H

°

ι

>

ο

w CM m

00 CM

t>

i-H

ω

u

α

Ο* +

W CM ιΛ

»

'S

^

Φ C φ

t -

ο co

1-Η

ιΗ ^

CO

CO Tf rH

iH 1 ω σ> • CM W

CM

CM

i-H

»-H

i-H

w CO CM

CM 1 w c*· m

i-H

ω

W CO ΙΛ

ω ** co

ω frin

ω ο t»

00

fr-

CO

ι—ι

i-H

iH

i-H CO 1ft

'if

CO

co

rH

fro> CM i-H

σ>

fr»

00 f co i-H

t i-H C-

+

00

+

^

^

eo i-H

co ιΛ

ω σ> φ CM ^

CO ο

1

ΙΛ I W CM OS

ω rH TT

00 C-

00 fr-

ΙΓ2

(Μ

CM

CM

CM

/•"s i-H 1 ω σ> • «ο

m 1 ω ο 00

CO

t— fr-

1 w fr-

1ft

CM

CM

s co co « co

frCM ιΟ i-H

co «-Η i-H »-H

m 00 r—(

σ>

co ο CO

CO co i-H

Φ

Φ

1 ω

I

σ> CM

ίύ

c» 1-Η

CM

ft 3 Ζ

I

ω

Φ

h φ

V

Φ

Λ

>.

to ti

Φ C φ

(Ο

C

05

Φ

Τ

h

Ό Ζ

•g

3 Ο

Φ FA

Ζ CO Ol

00

Vp/

ε ο

Ο

Ζ

•α

00

ω Β

**

ο

Λ

α

Ο ο

c

«β ti

c ο -·-> ο

A

Cu

>» bo in φ c φ

C

ΓC

φ

α

Ο

5 ^

β >

«Μ

C

tSJ

ΙΟ ο

cd

Ο

00

00

ο υ

Ζ

. ε

Λ

to

Ζ

=>

Ο.

•σ φ [κ «ο

00 bo
> .ο α) Η

"β ε


> >

Φ

ι ω

I w

I ω

ι Μ

ι ω σι

I ω

^ I W CO 00

τΗ I ω C—

αϊ

α

ι ω

I ω

ι ω σ>

ι ω ο

ι ω

^

Ν

Ι ω ο ιΛ

ω 1-H ο

eg 1 ω i-H CO

»-4 1 ω in T-t

ι ω

ο φ α

c

>>

Ο

bo

Ο

φ

Λ

C

α.

a)

eCM

00

t-

»-H

σ> ο σ>

Ν

CO 1 1

00 co

•

CNJ CO

ώ CO 00

β

/-Ν I

00 /-Ν β

α

>-

c

φ

ι.

φ Φ BS

«Μ

Χ

ο U

β

C-, Ν Ο σ>

U) l·.

5H 00 00

β

cq 1ft

Ό Ο

t00

00

Φ α σ> CO 1-H /—Ν β

ε ΙΓ3 CO 1—»

·—(

u σ> Ν

φ

Ba

ε ΙΛ 1—I

CO W i-H

m co co i-H

» Ü ΙΛ CO ι—Ι

Φ Ο σ> Tf »-Η

CO υ Ν CO 1-H

00 e-

CD Ρ0 00 ι-Η

co co σι

ΙΛ Tf CO

00 00 CO

CO co CO

Oi eg

Lrt co CM

CO CO co

£fcß ο u ω c 'C

ß s

>< CO 00

s a β

ΙΛ r-N a β

>t.

φ

>-

u

CO υ ο

σ> >> fcjO h

co CO 00 τ—(

φ c φ

τ

α> tu

ιΛ

ift CO σ>

& φ • /-Ν β


-

ο 00

CO ϋ σ> cq ι—Ι /—\

•

β Ν

CO Ο

^

tcg

T-t

CO υ CO CO «Η

CT> cvj

00 co eg

CO CO

CO CO ε in CO i—( /—Ν β

φ υ σ> co »—ι Ν β

A CO α co CO i-H

> Φ υ ο ιΗ

430

ü .α Λ

c ο 'S ω h U ο

υ

bo ® c υ

Ν I ω ο tft

f—( ω CO

ι-Η co — ιI 1 ω ω W 1 — t C * · » C CM t» CO O ^ — ιΙ f CO

ι-Η I ω CM OS m

— »4 t ω Ift as Ift

tH 1 ω Ο* 00 Ift

CM CM CM 1 ω W Μ T-t tco CO CM σ> as

CM 1 ω co ο (Ο

ι-Η «—t I 1 ω w as ο • 1-Η Sw/

iH 1 ω in Ift Ν«*

1-H 1 ω CM Ift Ift

i-H ω1 1-H Ift Ift

1-H 1 ω Ε — Ift Ift

CM 1 W ift CM CM

CO frco • cs CO CO CD CO CM CO co «—t 1-H CO

1-H 00 β 00 co

CM 00 • ο c-

t00 • CM C-

CO 1-H Ift 1-H 1-H 00 CO i-l 1-H Ift

CO 1 ω ift CS ^

TT •

C

Φ Ο co *H Oi

>> c b ο o ο SS CL,

o. 00 co ω as Ο

hC £ Φ C 4-I h φ

c 3 C O E" ift Ο α t> t> i-H co 1-H 00 CO C M in i-l co Oi Ift C ε irt 1-H -H 3 a) 1/ —\ Ο U I

tD

X

as 1-H

^

Η CM Ο CM

as as co co

CS 00 00 CO

tX) c-

Η

X

>—' Ό c cd υ c-a U to 00 00 CO ^

Ν ift co \ c £ ,Ω CL, c Ν C O Ο co CM co CO 00 os ο CO c,Ω c Cu co Ν Μ cn CO C ^ > C w fΛ ^ O. C •3· Ν

CM 1 a as ο as

1-H 1 ω 0-0 1 H

ι-Η 1 ω-» C

ι-Η I ω cσ> co Ift CO

I I W Η

^

cd α

C SS Λ! 1-H Ο cd c XI . ϊΩ ^ CL. cd CQ t—I to a μ ε

3 CÜ "» co a V»/ *o c Ν t·-Ζ 00 CO iH Ο

•o 2 t—

cd ffl äs η Ο /-ν

α

Ό 2

8

bo fc. >.

®

Ό

c α>

®

3

C C ο

ο

cd Η

47>48Sc).

A

similar

material

was

also

N a ) , Ca

analysed

by

Marshall 1 0 6 0 . - Cosmogenie material As is also true for water-related material, photon activation analysis has been applied for cosmochemical analyses in a few exceptional cases only. Mostly meteorites have been studied and there is only one report known by the authors in which instrumental

multielement

photon activation analysis of lunar material is

described (Hislop and Williams 1 0 2 7 ;

93)

The

earliest

see

a

jso

reports on multielement

Rev.65,85).

photon activation

analysis of

cosmo-

genic matter - as f a r as the the authors know - were published by Meijers (see Ref's.787,1061,

1062).

Since the ratios of Fe/Ni and Ni/Co reflect age and pro-

venience

of

meteorites

interest.

In

the

the

mentioned

method is presented

analysis thesis,

which

of

these

elements

an instrumental

are

of

cosmochemical

photon activation

analysis

enables fast and accurate determinations of

these

elements.

Pieces of meteorites were irradiated together with discs of iron,

balt and

nickel and of an alloy containing large concentrations

co-

of these

ele-

ments. the electron e n e r g y was 23 MeV at a mean beam current of 5 microamperes. The first measurment was made 10 minutes after irradiation with a Nal crystal to analyse the decay curve of Several subsequent periods

using

5 3 Fe

measurements

using the 511 keV annihilation

were then carried

a small G e ( L i ) - d e t e c t o r .

photopeak.

out after different

decay

The decay curves of longer-lived E>+-

emitters were also analysed using the mentioned spectrometer. Several first o r der interferences were quantified using the pure element samples which had been irradiated reaction

together

58Fe(y,np)

with

the

analytical

which is unlikely;

ions ^°Mn is mainly due to

57Fe(y,p)

samples.

56 Mn

was

attributed

under the described irradiation

to

the

condit-

and ®®Μη(η,γ), the latter induced by pho-

toneutrons. A careful accuracy assessment was made. The angular e n e r g y gradient and the gamma-ray counting statistical e r r o r were estimated as major sources of deviations of the results from the accurate values. However, comparison of the obtained data with literature values showed partly significant disagreement.

94) Meteorite material and several standard rocks were analysed using instrumental photon activation analysis by van Z e l s t 1 0 6 3 . Samples of powdered meteorites, ments

standard rock powders and a synthetic oxide mixture containing the eleof

interest

were

irradiated

at

two

different

bremsstrahlung

energies,

namely 40 and 20 MeV using 40 microamperes mean electron beam c u r r e n t .

The

513

h i g h e n e r g y i r r a d i a t i o n l a s t e d 1.5 h o u r s and t h e o t h e r one 2 h o u r s . Ca, C r , Fe a n d Ni w e r e a n a l y s e d . T h r e e h o u r s a f t e r t h e 40 MeV b r e m s s t r a h l u n g e x p o s u r e t h e •'fy.ln a c t i v i t y d u e to iron was m e a s u r e d

with a scintillation c r y s t a l . A f t e r a n -

o t h e r d e c a y p e r i o d of one d a y , t h e a c t i v i t y of 4 3 K o r i g i n a t i n g from calcium was ο d e t e r m i n e d u s i n g a 38 cm G e ( L i ) - d e t e c t o r . A f t e r a t h i r d cooling p e r i o d of a b o u t t h r e e d a y s , t h e gamma r a d i a t i o n of ^ N i ( f r o m Ni) was m e a s u r e d with t h e Ge(Li) s p e c t r o m e t e r .

I n t e r f e r e n c e d u e to t h e

24

N a a c t i v i t y r e s u l t i n g from m a g -

nesium and aluminium in t h e samples was a c c o u n t e d f o r u s i n g a c o r r e c t i o n c a l c ulation with help of t h e o t h e r g a m m a - r a y e n e r g y of

24

N a (2754 k e V ) . T h e 20 MeV

b r e m s s t r a h l u n g a c t i v a t i o n was c a r r i e d out f o r chromium a n a l y s i s t o avoid

first

o r d e r i n t e r f e r e n c e d u e t o ^ ^ F e i y . a n ) which h a s a h i g h t h r e s h o l d e n e r g y . T h e 320 keV g a m m a - r a y line of exposure

51

C r was m e a s u r e d a b o u t t h r e e w e e k s a f t e r b r e m s s t r a h l u n g

with a N a l - c r y s t a l .

Parallel a n a l y s e s of t h e s e e l e m e n t s p l u s

titanium

w e r e c a r r i e d out with p r o t o n a c t i v a t i o n a n a l y s i s u s i n g a s y n c h r o c y c l o t r o n

pro-

v i d i n g maximum p r o t o n e n e r g i e s of 52 MeV. Comparison of all o b t a i n e d v a l u e s f o r t h e s t a n d a r d r o c k s with l i t e r a t u r e v a l u e s yielded s a t i s f a c t o r y a g r e e m e n t f o r a few c a s e s .

It i s i n t e r e s t i n g t o note t h a t

except

photon activation analysis

re-

s u l t s on t h e a v e r a g e a r e somewhat h i g h e r t h a n t h o s e o b t a i n e d b y p r o t o n a c t i v a t ion a n a l y s i s f o r iron and nickel w h e r e a s t h e r e s u l t s f o r t h e o t h e r e l e m e n t s do not t e n d t o show a s y s t e m a t i c a l d i s a g r e e m e n t . 9 5) A meteorite sample was a n a l y s e d u s i n g i n s t r u m e n t a l p h o t o n a c t i v a t i o n a n a l y sis

within

a

largescale

systematic

investigation

about

photonuclear

reaction

y i e l d s ( K a t o e t a l . 9 1 9 ; s e e also R e v . 2 0 ) . Na, Mg, Ca, Ti, C r , Μη, Fe, Co, Ni, R b , Y, S r , Z r , N b , Ba a n d Ce w e r e a n a l y s e d with 30 MeV b r e m s s t r a h l u n g a c t i v a t i o n . Samples were i r r a d i a t e d f o r 1-6 h o u r s a t an a v e r a g e e l e c t r o n beam c u r r e n t of a b o u t 70 m i c r o a m p e r e s . M e a s u r e m e n t s were c a r r i e d out with a 33 c m 3 G e ( L i ) detector. presented.

An e x t e n d e d In

the

case

q u a n t i t a t i v e e v a l u a t i o n of f i r s t o r d e r i n t e r f e r e n c e s of

niobium

analysis

in t h e

meteorite

material

was

severe

i n t e r f e r e n c e d u e t o "^Mn p r o d u c e d t h r o u g h ® 4 F e ( y , n p ) was n e c e s s a r y ; a b o u t 50% of t h e total net 52

In

a r e a of t h e

935 keV g a m m a - r a y line was f o u n d t o be d u e

to

Mn.

the

following t a b l e ,

various

applications

of

photon

activation

l y s i s in t h e field of g e o - and c o s m o c h e m i s t r y a r e s u m m a r i s e d .

to t h e

ana-

514 T a b . 6 . 2 - 7 : Application of instrumental photon activation analysis in geochemistry Bremsstr. Material analysed

energy,MeV

Rev.

(I e .WA)

Elements determined

Ref.

no.

Rock samples

variable

Zr

705

80

Meteorites

23 ( 5 )

Fe, Ni, Co

787,1061, 93 1062

Mg, Ca, Ti, Ni

1049

82

45 (not given)

Mg, Ca, Ti,

1050

83

Sea water

30 ( 3 0 )

Sr

1057

90

Meteorites

40 (40)

Ca, Cr, Fe, Ni

1063

94

Ores,

25 (not given)

Rb, S r , Zr, Nb, Sn, Cs, Ta

257

84

Ca, Ti, Cr, Fe, S r , Zr, Sb,

1027

85

1000

47 86

Rock samples

23, 28 (not given)

Rock samples,

Sr

sediments

various geol. material Lunar rocks

35-40 ( 4 - 8 )

Cs, TI Rock samples

30 (600 mA max.)

Rock samples

30 ( 9 0 )

Te Na, Mg, Ca, Ti,

Cr, Μη, Fe,

1051,

Co, Ni, Rb, S r ,

Y, Zr, Nb,

1052

Ba, Ce Minerals

12-30 (variable)

F, Na, Mg, Al, Ca, Ti, Mn,

251

Fe, Cu, Zn, As, S r , Zr, Nb, Mo, As, Cd, S b , B a , VV, Au, Pb Various geol. material

25 (not given)

F, Cl, Ti, Cu, Se, Rb, S r , Zr, Cd, Sn, Ba, Ta

261

515

Tab.6.2-7,

continued Bremsstr.

Material analysed Rock samples

e n e r g y , f.leV

Rev.

(Ie.uA)

Elements determined

Ref.

no.

not given

Mg, Ca, Ti,

1053

87

Zr,

Cr, Μη, Ni, Sr,

Nb

Minerals

8, 14 (700)

Ta, Au

1160

Rock samples,

30 (70)

Ni

1054

88

919

95

91

glass Meteorites

30 (70)

Na, Mg, Ca, Ti, Cr, Mn, Fe, Co, Ni, Rb, Sr,

Y, Zr,

Nb,

Ba, Ce

Marine sedim.

30 (70)

Na, Mg, Ca, Ti,

Cr, Mn, Fe,

1058,

Co, Ni, Rb, Sr,

Y, Zr, Nb,

1114

Ba, Ce

Suspended matter 35 (110)

Si, Ni, Y, Z r , Sb, T l , Pb, Bi

Various geol.

Na, Sc, Co, Ni, As,

30 (not g i v e n )

Rb

1006

55

1059

92

1055

89

material

Rock samples

8 (500-1000)

Se, B r , Y , A g , Ba, Er, Hf, W, Au

516

6.2.4.5

Analysis of raw materials and industrial products

T h i s paragraph is divided into four sections. In the f i r s t , works about analyses of ores and ore-related products are reviewed.

In the second section,

pers about analyses of metal matrices are discussed, fuel

materials

and

in the last

section

analyses of

pa-

in the third, analyses of miscellaneous

matrices

are

presented.

- Ores and ore-products In

reviewing

the

literature

about

instrumental

photon

activation

analysis

of

raw products, ore analyses were found to dominate. Frequently, as already noted in the preceding

paragraph,

ore analyses are combined with analyses of other

geological material because both materials are of similar provenience and thus have a similar matrix. ton

spectra

quality.

after

Hence relevant factors like shape of the resulting

activation,

Normally,

signal-to-Compton

equal reference

ratios

etc.

are

materials can be used in the

of

pho-

similar

instrumental

photon activation analysis of both species. T h e r e f o r e , analyses of ores and r e lated materials were frequently reported in papers reviewed in the

preceding

paragraph.

Frequently,

Noble Metals are of major interest in the analysis of o r e s .

fore,

many works in this field have been concerned

gold,

silver and the platinum group metals.

There-

with the determination of

poo 96)

In

the

work

bremsstrahlung given

of

Iiapitsa

source.

so that it is

et al.

,

Unfortunately,

not

known

if it

an electron

cyclotron

was a microtron

t y p e . Gold was analysed using the production of ation.

100-200

g

of

powdered

gold

was used as a

no description of this accelerator

ore

material

or a different

was

machine

by isomeric photoexcitwas

packed

in a

plexiglass

container and located in front of the tungsten converter target at a distance of 10 cm. A monorail carriage transport system was used for sample t r a n s f e r . Samples were then irradiated with 9 MeV bremsstrahlung at an average electron beam current of 30 microamperes. The exposure time was 18 seconds which means that

the

induced

activity

(the half-life of * ^ m A u to

the

detector.

Since

yield

j s 7.3 the

function s).

nearly

reached

its

saturation

range

The sample container was then transported

transfer

line

terminated

directly

at the

detector

(Nal well-type crystal connected to a single channel analyser and a scaler) the induced activity could be measured without any further delay; the total cooling period was as small as 3 s. Samples were measured f o r 18 s. Analysing the r e -

517 suiting s p e c t r u m , it had previously been found that u n d e r t h e described c o n d i tions the photopeak which was located closest to the 279 keV line of ^ ' m A u was the 217 keV gamma-ray line of l 7 9 m H f originating from hafnium sometimes p r e s e n t in the ore samples.

However, the resolution capability allowed a complete s e -

paration of t h e analysed photopeak from any signal in the neighbourhood. T h r e e micrograms per gram were found to be the detection limit of the method. The most evident a d v a n t a g e of the method is its r a p i d i t y ; large numbers of a n a l y s e s , several t e n s of t h o u s a n d s per y e a r , could be performed. 97) A compilation of photonuclear data of several selected elements f r e q u e n t l y encountered in copper mining p r o d u c t s was p r e s e n t e d by Ratynski et al.*"®^. Elements were included which either were analysed in the material or c o n t r i b uted to t h e i n t e r f e r i n g background radiation. The a u t h o r s underlined the u r g e n t need of systematic photonuclear data compilations,

p r e f e r a b l y based upon e x -

perimentally obtained r e s u l t s , to s e r v e as a r e f e r e n c e d u r i n g practical a n a l y s is work. The above listed elements were irradiated as such with a 30 MeV b e t a tron at d i f f e r e n t electron energies ranging from 15-30 MeV. Then they were ο measured with a 20 cm J Ge(Li)-detector a f t e r d i f f e r e n t cooling periods. The reactions of Ti, Cu, Mo and Rh were evaluated and discussed in detail. 98) The analysis of gold and silver in rocks and ores was r e p o r t e d by Kapitsa et al.^®*. A microtron was used for irradiation at d i f f e r e n t e n e r g i e s , namely 9 MeV ( a v e r a g e electron beam c u r r e n t : 30 microamperes) and 14 MeV (20 microamperes).

With help of the lower e n e r g y ,

toexcitation were included ( 1 " ^ m A g , higher energy,

1(

activities due to isomeric state

^mAg,

1

pho-

^ 7 m A u ) and by irradiation at the

( y , n ) - r e a e t i o n s were e f f e c t e d . The isomers could be measured

fairly i n t e r f e r e n c e - f r e e with a Nal spectrometer whereas the photonuclear p r o d u c t s had to be counted with a semiconductor d e t e c t o r because of the somewhat more complex gamma-ray s p e c t r a due to reaction p r o d u c t s of o t h e r elements p r e sent in the sample (Ba,

Pb).

99) The photon activation analysis ο

*"h, Pd, Ag, I r , Pt and Au in Black Con-

c e n t r a t e s ( r e s i d u e s of o r e - p r o c e s s i n g s t e p s which a r e rich in precious metals, e . g . copper ore r e s i d u e s ) was r e p o r t e d by Breban et al.

About 20 mg of

sample material were mixed with cellulose powder and p r e s s e d to a 1 mm thick pellet with 1 cm diameter. This was done to avoid e r r o r s by self-absorption of s o f t gamma-rays within the matrix d u r i n g activity c o u n t i n g . Pure element discs having the same s h a p e s as t h e samples were used a s r e f e r e n c e materials. Samples and element s t a n d a r d s were sandwiched and then irradiated with 35 MeV b r e m s s t r a h l u n g ( a v e r a g e electron beam c u r r e n t = 66 microamperes) of an electron

518 linear a c c e l e r a t o r . tectors.

Gamma a c t i v i t y measurements were performed with

Possible i n t e r f e r e n c e s were studied in detail,

spectra

and

also literature

data.

Detection

limits

Ge(Li)-de-

using the pure

were

found

element

between

20 ng

( f o r A u ) and 6 micrograms ( f o r A g ) . The r e p r o d u c i b i l i t y of the obtained results varied

from

1 to 7%. Comparison

with the results of classical methods

yielded

excellent agreement in the most cases.

100) Copper was analysed in ores and flotation products using instrumental photon activation of

analysis b y Pradzynski^"®®.

A betatron

was used f o r

100 g - b a t c h e s of sample material with 13,6 MeV b r e m s s t r a h l u n g .

activation Irradiation

time was 10 minutes, decay period 1 minute and the samples were measured f o r 5 minutes

with

a

scintillation

spectrometer.

The

511 keV

annihilation

radiation

photopeak of ® 2 Cu was used f o r analysis evaluation. It was found that the only two elements activable at this e n e r g y and present in considerable concentration in the analysed material were s i l v e r and lead. bute to the measured

peak

significantly.

Both components did not c o n t r i -

In the r a n g e of 0.3 to some tens of

p e r cent of c o p p e r to be analysed,

the accuracy

were

activation

excellent.

Instrumental

photon

and precision

analysis

all other methods considered in the described task analysis,

X - r a y fluorescence

of the

was found

method

superior

(14 MeV neutron

to

activation

spectrometry).

101) A betatron was used f o r instrumental photon activation analysis of niobium and tantalum in ores b y

Galatanu2''®®.

T h e s e elements are d i f f i c u l t to

separate

b y chemical analysis, hence an instrumental method of determination was s o u g h t . 1-2 g powdered o r e material was irradiated f o r 2 hours with 25 MeV bremsstrahlu n g . No information about the electron beam current was g i v e n ; the i n t e g r a l i r radiation period

dose

rate

samples were

the resulting

at the irradiation

site

was 2600 R/min.

measured f o r the f i r s t time.

After

10 m decay

Because of the complexity

gamma spectra a semiconductor detector

had to be used.

In

of the

f i r s t measuring period, the e n e r g y range between 50 and 550 keV was r e c o r d e d to detect the low e n e r g y 1 8 0 m j a g a m m a radiation (93 and 103 k e V ) . A f t e r a second cooling

period of

70 minutes the e n e r g y

range

between

500 and

1050 keV

screened with help of a biased amplifier and the 935 keV gamma e n e r g y of was measured.

Possible

sources of i n t e r f e r e n c e including

w e r e studied and discussed in detail,

reproducibility

was checked

by

radioactivity

but in the g i v e n analysis task t h e r e was

no e v i d e n c e of any significant i n t e r f e r i n g a c t i v i t y

The

natural

was

92mNb

replicate

yield.

analyses

and

found

within £5%.

Sensitivities of 0.01% f o r Nb and 0.001% f o r T a were achievable under the d e s c ribed experimental conditions,

with a total r e l a t i v e e r r o r of less than 10%.

519 102) Within an extended

study

of isomeric photoexcitation

its application

to

the analysis of noble metals in metallugical r e s i d u e s was r e p o r t e d by Breban et a l . 6 - 8

MeV b r e m s s t r a h l u n g (mean electron beam c u r r e n t = 70 microamperes at

7 MeV) of an electron linear accelerator was used f o r activation of 10-20 g of powdered sample material.

Because of the v e r y s h o r t half-lives of some of the

product activities a fast sample t r a n s f e r had to be u s e d . The available system permitted sample t r a n s p o r t a t i o n time of some two s e c o n d s . For t h e determination of Rh, Ag, I r , Pt and Au in several matrices, samples were i r r a d i a t e d for 0.5 o r 1 m, total cooling time including sample t r a n s f e r was about 3 seconds. The samples were then counted for 1 o r 2 m. Since t h e gamma-ray e n e r g i e s of some of the activation p r o d u c t s were v e r y close to each o t h e r , Ge(Li) s p e c t r o m e t r y had to be used for gamma c o u n t i n g . As found t h r o u g h replicate a n a l y s e s and comparison

with

r e s u l t s of other methods,

precision and accuracy,

the obtained values showed

satisfactory

r e s p e c t i v e l y . However, the values a r e of good quality

only at r a t h e r high concentration to be determined, namely s e v e r a l h u n d r e d s of micrograms per gram minimally. 103) Photoexcitation of the isomeric state was used for the analysis of t u n g sten

in ores and

related

material as reported

by Kodiri et a l . 1 0 6 7 .

6 g of

sample material were i r r a d i a t e d with 5 MeV b r e m s s t r a h l u n g of an electron linear accelerator f o r 15 seconds (mean electron beam c u r r e n t = 7 00 microamperes). A fast pneumatic sample t r a n s f e r allowed 3 seconds total c o d i n g period and the induced activity was then measured f o r 15 s. The 60 keV gamma peak of 183mw (T=5,3 s ) was measured

with a scintillation

spectrometer.

i n t e r f e r e n c e was due to barium producing ^^ 7 m Ba, contribution,

in the case of barium concentrations

The only

possible

but it was found that this comparable with those of

t u n g s t e n , may be d i s r e g a r d e d . The total experimental period amounted to about 30 s . 0.3 mg was found to be the experimental sensitivity of determination. The precision was given as maximally 5%. Comparison of the r e s u l t s with values of o t h e r methods yielded an accuracy of 5-10%, depending upon the concentration to be determined.

The major advantage of this p r o c e d u r e is its relative rapidity

and selectiveness.

104) The multielement instrumental photon activation analysis of a phosphate ore sample was r e p o r t e d by Galatanu and E n g e l m a n n 1 0 6 8 ; see also R e f . 1 0 6 9 . 0. 5 g b a t c h e s were i r r a d i a t e d with b r e m s s t r a h l u n g of an electron linear accelerator. To avoid i n t e r f e r e n c e by unwanted reactions of some components with p h o t o n e u t rons,

the i r r a d i a t e d

materials were wrapped in 0.9 mm thick cadmium foil. A

s y n t h e t i c multielement r e f e r e n c e material was p r e p a r e d mixing components of as many as 49 elements with calcium phosphate, so that between 0.001 and 0.1% of

520

each element was p r e s e n t .

T h e use of t h i s kind of r e f e r e n c e material - a s a l -

r e a d y mentioned - is somewhat p r o b l e m a t i c s i n c e f r e q u e n t l y c o m p o n e n t s a r e p r e sent

in c o n s i d e r a b l e

concentrations

which a r e

not of i n t e r e s t in t h e

analysed

material a n d e v e n t u a l l y d i s t u r b t h e e v a l u a t i o n p r o c e d u r e by p r o d u c i n g i n t e r f e r ing b a c k g r o u n d r a d i a t i o n . As e x p l a i n e d a b o v e in p a r a g r a p h 6 . 2 . 2 , t h e u s e of a r e f e r e n c e material is r e c o m m e n d a b l e which is similar to t h e material to be a n a l y s e d with r e s p e c t to t h e m a t r i x composition ed w o r k )

(which was t h e c a s e in t h e r e v i e w -

b u t also - a t l e a s t to a minor e x t e n t - in t h e c o n c e n t r a t i o n s of t h e

minor and t r a c e

components.

Two d i f f e r e n t i r r a d i a t i o n e n e r g i e s w e r e u s e d , namely 18 MeV (mean e l e c t r o n beam current

= 60 m i c r o a m p e r e s )

and

30 MeV (90 m i c r o a m p e r e s ) .

The first electron

e n e r g y was s e l e c t e d f o r t h e i n t e r f e r e n c e - f r e e a n a l y s i s of CI, K, S r , Cd a n d Pb a f t e r an e x p o s u r e period of 1 . 5 h o u r s . All o t h e r e l e m e n t s were a n a l y s e d u s i n g a f o u r h o u r e x p o s u r e of t h e material to b r e m s s t r a h l u n g of t h e l a t t e r e n e r g y .

The

r e s u l t i n g g a m m a - r a y s p e c t r a were t a k e n with a Ge(Li) s p e c t r o m e t e r . T h e following elements could be a n a l y s e d in t h e p h o s p h a t e s a m p l e : Na, CI, K, Ti, C r , Μη, C o , Ni, Z n , A s , Se, R b , S r , Y, Z r , N b , Mo C d , S b , I, C s , Ba, C e , Pb a n d U. T h e o b t a i n e d s e n s i t i v i t i e s w e r e between 500 n g / g ( f o r Z r , Nb a n d Sb) and 125 micrograms

per

gram

(for

K).

The

reproducibility

was

fairly

good

in t h e

most

c a s e s . Since no c o m p a r a t i v e r e s u l t s from o t h e r m e t h o d s w e r e g i v e n t h e a c c u r a c y of t h e data is u n k n o w n . All k i n d s of p o s s i b l e i n t e r f e r e n c e s were d i s c u s s e d extensively. ever

occur

Although in

they a r e based

this

interferences

matrix,

the

were included

given

quantitative

which a r e most yields

are

very

unlikely

valuable

to

since

upon e x p e r i m e n t a n d t h u s can be r e f e r r e d to by o t h e r a n a l y s t s

w o r k i n g u n d e r similar c o n d i t i o n s .

- Metals 105) T h e r e p o r t by S c h w e i k e r t a n d A l b e r t p r e s e n t e d a t t h e IAEA Symposium on Radiochemical Methods of Analysis 9 "·* ( s e e also R e v . l ) c o n t a i n s one of t h e f i r s t applications ments

in

of photon a c t i v a t i o n

metal

matrix.

Zirconium

analysis

to t h e d e t e r m i n a t i o n

was d e t e r m i n e d

in h a f n i u m

of h e a v i e r using

ele-

activation

with 27 MeV b r e m s s t r a h l u n g (mean e l e c t r o n beam c u r r e n t = 50 m i c r o a m p e r e s ) . E x p o s u r e time was 5 m i n u t e s . "® m Zr was m e a s u r e d u s i n g Nal s p e c t r o m e t r y . An e x p e r i m e n t a l d e t e c t i o n limit of 100 ng Zr was f o u n d . Silver was a n a l y s e d in b i s muth matrix u s i n g t h e r e a c t i o n MeV

bremsstrahlung

t h e annihilation

A f t e r 25 m i r r a d i a t i o n with 27 radiation

peak a t

511 keV was

e v a l u a t i o n . Due to t h e lack of high r e s o l u t i o n s p e c t r o m e t e r s a

used

for

521

106) T h e e x t r e m e d i f f i c u l t i e s of i n s t r u m e n t a l p h o t o n a c t i v a t i o n a n a l y s i s a t time b e f o r e t h e

general

availability

of h i g h - r e s o l u t i o n

m o n s t r a t e d in t h e p a p e r of K o r t h o v e n et a l .

detectors

the

a r e well d e -

a b o u t t h e a n a l y s i s of gadolinium

a n d europium in t u n g s t e n b r o n z e s . T h e t i t l e of t h e a r t i c l e d e s c r i b e s t h e method a s " c o m p u t e r r e s o l u t i o n gamma s p e c t r o m e t r y " . T h e b r e m s s t r a h l u n g r a d i a t i o n s o u r ce u s e d in t h i s work was an e l e c t r o n s y n c h r o t r o n , photon

activation

analysis

only

in

comparatively

which h a s b e e n applied to few c a s e s

hitherto.

Instru-

mental p h o t o n a c t i v a t i o n a n a l y s i s was t h e method of t h e choice in t h i s c a s e f o r two r e a s o n s .

First,

t h e a n a l y s i s of t u n g s t e n

bronzes by classical chemistry is

s e v e r e l y h a m p e r e d b y t h e i r r e s i s t a n c e a g a i n s t chemical a t t a c k ; it i s a long a n d t e d i o u s p r o c e d u r e to d i s s o l v e t h e m . S e c o n d , t h e r m a l n e u t r o n a c t i v a t i o n a n a l y s i s is suspect

b e c a u s e of t h e s i g n i f i c a n t f l u x g r a d i e n t of t h e n e u t r o n beam

i t s p a t h t h r o u g h t h e sample d u e t o t h e e x t r e m e l y h i g h t h e r m a l n e u t r o n tion c r o s s s e c t i o n ,

along

absorp-

p a r t i c u l a r l y of gadolinium.

Samples w e r e i r r a d i a t e d with 70 MeV b r e m s s t r a h l u n g . T h e r e was no comment on t h e e l e c t r o n beam c u r r e n t . T h e t u n g s t e n c o n t e n t of t h e sample m a t r i x was u s e d a s an internal standard bremsstrahlung

f o r calculation of e r r o r s c a u s e d b y t h e i n h o m o g e n e i t y of t h e

p h o t o n b e a m . M i x t u r e s of t h e c o r r e s p o n d i n g R a r e E a r t h

oxides

with WO.J a s well a s s i n g l e s a m p l e s of e a c h matrix component w e r e u s e d a s r e f e r e n c e m a t e r i a l s . E x p o s u r e p e r i o d s were 5 o r 20 m i n u t e s . Samples w e r e t h e n c o u n t ed s e v e r a l times with a Nal s p e c t r o m e t e r . A s o p h i s t i c a t e d c o m p u t e r p r o g r a m was u s e d t o r e s o l v e t h e v e r y complex s p e c t r a . T h i s p r o g r a m yielded s t r i k i n g l y a c c u rate

results

spectra,

under

t h e following c o n d i t i o n s :

(b) equal exposure,

(a)

well-known

single

component

cooling a n d c o u n t i n g p e r i o d s f o r samples a n d a s -

sociated r e f e r e n c e materials. 107) Chemical s e p a r a t i o n p r o c e d u r e s were a p p l i e d in t h e p h o t o n a c t i v a t i o n lysis

of

Rev.8).

several

e l e m e n t s in

metal m a t r i c e s

(Debrun

and

Albert®1^,

see

anaalso

Major a t t e n t i o n was d i r e c t e d to e l e m e n t s which c a n n o t r e a d i l y be a n a -

l y s e d b y t h e r m a l n e u t r o n a c t i v a t i o n a n a l y s i s , namely Ni, T1 a n d P b . T h e s e were a n a l y s e d in Co, Cu a n d Cr m a t r i x . Samples were i r r a d i a t e d with 35 MeV b r e m s s t r a h l u n g (mean e l e c t r o n beam c u r r e n t = 50 m i c r o a m p e r e s ) f o r 20 m. M e a s u r e m e n t s w e r e p e r f o r m e d with a Nal s p e c t r o m e t e r . No d e f i n i t e r e s u l t s w e r e g i v e n b u t e x p e r i m e n t a l s e n s i t i v i t y d a t a w e r e given c o m p a r a t i v e l y to v a l u e s of t h e r m a l n e u t ron a c t i v a t i o n a n a l y s i s a s a c o m p l e m e n t a r y

technique.

108) A m i c r o t r o n was u s e d a s an a c t i v a t i n g b r e m s s t r a h l u n g s o u r c e in t h e a n a l y s i s of Ge, Zr a n d Mo in metals and alloys a s d e s c r i b e d b y S a m o s y u k et

al.2^.

T h e s e a n a l y s e s were p e r f o r m e d within a s t u d y of t h e a p p l i c a b i l i t y of a micro-

522

tron

for

activation

photoneutrons.

analysis

(a)

with

both

high

energy

photons as well as with

Analysis of 20-30% of germanium in Nb-Ge alloys;

samples

were irradiated with 29,2 MeV bremsstrahlung of a microtron (mean electron beam current = 10 microamperes) and counted with a 21 c m ' G e ( L i ) detector. The r e sults were compared with those obtained by other methods and good agreement was stated. One of these comparative methods was the activation analysis with photoneutrons from the same microtron. This comparison was not possible in another application

example,

namely

(b)

the determination of zirconium in concentrat-

ions between 0.8 and 2% in Nb-Zr alloys; both the low neutron activation cross section of zirconium and the background interference due to tantalum present in the sample did not allow a zirconium analysis by activation with either photoor pile neutrons. ternal

monitor,

In this ease the matrix-inherent niobium was used as an i n -

(c)

Analysis of molybdenum

0.1%) in a multiphase alloy; m.

A f t e r a cooling

spectrometer

period

wet

2%) and zirconium

of a few minutes samples were measured

mentioned above.

spectrometry,

(about

(about

40-50 mg of samples were irradiated for 15 to 20 with

the

Comparative results were obtained by emission

chemistry and neutron activation

analysis.

The

comparison

showed excellent agreement between the methods.

In

the

systematic

study

measured for nearly

reported

in this article

analytical

sensitivities

all elements of the Periodic Table for activation

were

analysis

with both photons and photoneutrons as supplied by the same source; the obtained

sensitivity

sensitivities

results

partly

were in disagreement

determined in the laboratory

of

to experimentally

obtained

the authors of this book

(Sege-

bade et a l . 1 0 7 0 ) . 109) The instrumental photon activation analysis of Pd, A g , Pt and Au in high purity copper was reported by Segebade et a l . l "

1

? ! » 1072^ This

W O rk

was p e r -

formed within the certification procedure of several candidate reference materials. The samples lay before as 1 g discs with 13 mm diameter or as granulate. T h e y were synthesised by melting the mentioned elements in zone-melted ultrapurity

electrolytic

copper.

The

trace elements

were

present

in the

following

concentration ranges (in micrograms per g r a m ) : Pd and Pt: 1-100, A g : 1000-5000, and A u :

10-100.

In order to have a record of the accuracy and also to check the applicability of the method for instrumental analysis of Noble Metals in general, a reference material containing

certified

concentrations

of all Noble Metals was also ana-

l y s e d . The pure elements in appropriate forms (discs or powdered,

respectively)

were used as reference materials. The Pd- and Pt-containing samples were also

523 analysed by radiochemical photon activation analysis using separation by electrolysis,

ion exchange or coprecipitation.

The samples and reference materials

were sandwiched and exposed to 30 MeV bremsstrahlung of an electron linear a c celerator (mean electron beam current = 150 microamperes) for 1-3 hours depending upon the expected concentration. In the case of radiochemical analysis, cooling

periods,

including

the separation step,

were about six hours.

the

These

samples were measured with a well-type Nal c r y s t a l . The counting times varied between one hour and one day depending upon the induced activity levels. The other samples were allowed to cool for six days and then measured with a semiconductor

detector.

Both a conventional large

volume coaxial

Ge(Li)-detector

and a planar low energy photon germanium diode were used. During practical work it has been proved that in many cases low energy photon spectroscopy is s u p e r ior to classical gamma spectroscopy

(see above in paragraph 6 . 2 . 3 . 2 ) . One of

the reasons is the fact that frequently the low energy part of the photon s p e c trum of photon activated specimens contains fewer energy lines than the high energy partition. This is particularly true for Pd and A g . The obtained trations with

the

results showed excellent agreement

calculated

by

results

of the

certification

the

campaign.

element

other

ratios of the

laboratories

The concentration

with the theoretical concensynthetic

participating

mixture and

in the

also

interlaboraty

data obtained in the analysis of the

certified r e f e r e n c e material (SARM 7, Platinum ore sample, South African Bureau of

Standards)

agreed

fairly

well with

the certified

values;

the

precision

of

these data was somewhat poor because of the low Noble Metals concentrations (from 63 n g / g for osmium to 3.74 micrograms per gram for platinum) and the high activity background effected by the complex matrix composition. The precision achieved in the analysis of the high purity copper samples was good to excellent

except

for

the

lowest

gold values

(0.001%).

A radiochemical

separation

would have been necessary to improve the precision of the data. An instrumental method required,

neutron activation analysis would be the method of the choice

in this case because of its better intrinsic sensitivity for gold. - Fossile fuel material As is the case in the instrumental photon activation analysis of biological material,

the

application

to the

analysis of fossile

fuel material is of

particu-

lar advantage because of the absence of components producing long-lived i n t e r fering

matrix activities;

from the matrix is due to

the

most prominent

background radiation

originating

with a half-life of 20 minutes. Therefore,

samp-

les can be counted a few hours after activation. If radionuclides with say min-

524 u t e s of h a l f - l i v e s

(28A1,

29

A1,

38

K

etc.)

have to be c o u n t e d ,

samples must

i r r a d i a t e d at an e l e c t r o n e n e r g y lower than t h e ( y , n ) - t h r e s h o l d of * 2 C ,

be

namely

a t l e s s than 20 MeV. 110) In a p a p e r by Galatanu and E n g e l m a n n 1 ^ 7 3 t h e i n s t r u m e n t a l photon a c t i v a t ion a n a l y s i s o f 28 t r a c e elements in a coal sample is d e s c r i b e d . ment

mixtures

were

used as r e f e r e n c e

materials.

Different

Synthetic

b a t c h e s of

ele-

samples

and r e f e r e n c e materials were i r r a d i a t e d at two e l e c t r o n e n e r g i e s , namely 18 MeV (mean e l e c t r o n beam c u r r e n t = 60 microamperes) and 30 MeV (mean e l e c t r o n beam current

= 90 m i c r o a m p e r e s ) .

counted

for

The

samples a c t i v a t e d

at t h e lower e n e r g y

t h e f i r s t time a f t e r a few minutes a f t e r irradiation

ones a f t e r 15 h o u r s .

and t h e

E v e r y sample was counted s e v e r a l times to d e t e c t

were other

eventual

s p e c t r a l i n t e r f e r e n c e s . Gamma s p e c t r o s c o p y was performed with a 79 cm 3 G e ( L i ) d e t e c t o r . T h e following elements were a n a l y s e d : Na, Mg, CI, K, C a , T i , C r , Μη, F e , C o , Ni, Z n , A s , S e , R b , S r , Y , Z r , Nb, Mo, C d , S b , I , C s , B a , C e , Pb and U. Among t h e s e , CI, K, S r , Cd and Pb were a n a l y s e d in t h e sample b a t c h e s i r r a d i a t ed with 18 MeV b r e m s s t r a h l u n g .

T h e a c h i e v a b l e detection limits varied

between

0 . 2 and 125 micrograms p e r g r a m .

T h e r e p r o d u c i b i l i t y of t h e a n a l y s i s data was

obtained

was

by

triplicate

were no comparative no c e r t i f i e d

analysis;

the described

fairly

good

for

most

elements.

values from o h e r a n a l y s i s t e c h n i q u e s a v a i l a b l e .

multielement

l e s as s e c o n d a r y

it

Moreover,

r e f e r e n c e material was a n a l y s e d along with t h e

standards.

method.

There

Therefore,

no a c c u r a c y

samp-

values could be given

An e x t e n d e d i n t e r f e r e n c e a s s e s s m e n t was i n c l u d e d .

for This

was a l r e a d y d i s c u s s e d in t h e review of a n o t h e r p a p e r of t h e same a u t h o r s * " ® 8 ; s e e also R e v . 1 0 4 . 9 Q fi 111) Brown coal was a n a l y s e d by L e o n h a r d t et a l . i n c l u d i n g i n s t r u m e n t a l photon activation a n a l y s i s .

using d i f f e r e n t

techniques

A microtron was used to a n a -

l y s e C a , Fe and S r . T h e a u t h o r s did not g i v e any description of sample mass and its p r e p a r a t i o n . beam c u r r e n t

21 MeV b r e m s s t r a h l u n g was used for activation

= 5 microamperes).

No i r r a d i a t i o n ,

(mean

electron

cooling and c o u n t i n g

periods

were mentioned and also t h e gamma s p e c t r o m e t e r was not s p e c i f i e d . Anyhow, r e g a r d i n g t h e irradiation not r e q u i r e d ) ; and

1.5% ( f o r c a l c i u m ) .

were

obtained

cases

severe

and

precision

by P r i n g l e et

parameters,

the analysed by

a t r a c e a n a l y s i s was not p o s s i b l e (and also

concentrations

T h e precision

radionuclide

excited

lay

between

was 5-10%. X-ray

were

sufficient.

Comparative

fluorescence

d i s a g r e e m e n t o f t h e data was f o u n d , al.1074.

0.04%

(for

strontium)

values

analysis.

for

iron

In

some

but in g e n e r a l t h e a c c u r a c y

T h e a n a l y s i s of coal samples was also

reported

525

- miscellaneous materials 112) Fluorine and potassium were analysed in Z r 0 2 used as ground material f o r n c n

i n d u s t r i a l ceramic p r o d u c t s (Galatanu et al. was used for activation. irradiated

) . B r e m s s t r a h l u n g of a betatron

For fluorine analysis,

batches of the material were

with b r e m s s t r a h l u n g from 11.9 NleV e l e c t r o n s to avoid i n t e r f e r e n c e

from the zirconium

matrix;

the most prominent possibly i n t e r f e r i n g zirconium

reaction is ®"ζΓ(γ,η)®^ΖΓ with a threshold e n e r g y of about 12 MeV. In previous experiments it was found that using this b r e m s s t r a h l u n g e n e r g y ,

t h e r e is no

i n t e r f e r i n g photon radiation to be expected in the r a n g e between 400 and 700 keV of t h e r e s u l t i n g gamma-ray s p e c t r u m . T h e r e f o r e , Nal spectroscopy was used to analyse

the annihilation

radiation of

non-destructively.

The maximum

possible electron e n e r g y of the machine (26.5 MeV) was used to activate o t h e r b a t c h e s of the analysis material for potassium determination.

Because of mul-

tiple i n t e r f e r e n c e , high-resolution gamma spectrometry had to be used f o r measOQ urement of t h e 2167 keV gamma-ray line of °°K. A detection limit of about one mg was found for both elements analysed using the described p r o c e d u r e . value does not a g r e e with other sensitivity data r e p o r t e d in the

This

literature.

However, it may be considered reliable since it was obtained by experiment and the sensitivity calculation was carried out v e r y c o n s e r v a t i v e l y . 113) The analysis of s e v e r a l toxic components of PVC material was r e p o r t e d by Kondo^" 7 ®. The analysis of toxic elements in plastic material is of importance because the material is in widespread daily use and incorporation of any of its components is likely. F r e q u e n t l y , c h i l d r e n ' s toys a r e made of PVC and i n v e s t igations have shown t h a t both the toxic matrix and o t h e r components can be leached out and eventually incorporated by the child which might lead t o s e v e r e illnesses and diseases. In the article of Kondo, t h e analysis of Zn, Cd, Ba and Pb in PVC s h e e t s by photon activation is d e s c r i b e d . P u r e elements (Zn, Cd and Pb) o r stoichiometrically well-determined compounds (sodium chloride and barium n i t r a t e ) were used as r e f e r e n c e materials. The samples were irradiated with 16 MeV b r e m s s t r a h l u n g (mean electron beam c u r r e n t : 20-30 microamperes) and m e a s u r ed with a 40 c m ' G e ( L i ) - d e t e c t o r .

Because of the low activation e n e r g y t h e r e

was no b a c k g r o u n d radiation due to the matrix carbon and only relatively small contribution from 34m£j p r o d u c e < j in the matrix chlorine. Moreover, some of t h e elements to be analysed could be measured a f t e r ^ 4 m Cl had decayed to negligible activity and t h e r e w i t h , the gamma-ray specta were not i n t e r f e r e d by any matrix b a c k g r o u n d a c t i v i t y . The analysed concentrations were between 0.06 and 1%.

526 114) The instrumental photon activation analysis of glass matrix was described by Hislop and Williams 9 ^. NBS standard glass material was analysed. A s y n t h e tic multielement reference material was prepared by mixing oxides of as many as 39 elements with a synthetic average glass matrix. This reference material was already

discussed

in

6.2.4.3

about

the

analysis of biological material

(Rev.

6 5 ) . Sample and reference material were sandwiched together and irradiated with 35-45 MeV brems Strahlung for one hour at a mean electron beam current of 5-10 microamperes. Another batch of the sample was irradiated with 17 MeV b r e m s strahlung from an electron beam of 50-60 microamperes.

Samples and reference ο materials were measured multiply in increasing intervals using a 40 cm G e ( L i ) detector.

In the case of the lower energy activation,

the special advantage is

the low activity background contribution of the matrix. As, S r , Zr, S b , Cs, Ce, Tm and T1 were analysed quantitatively in the NBS r e ference glass. However, line seems

somewhat

the analysis of thulium using the 198 keV gamma-ray

questionable because of probable strong interference

by

120mgj3 f r o m antimony present in the sample. The obtained values and the c e r t i fied data - if any available - agreed well within the precision of the method. The analysis of glass matrix is also discussed in the forensic context in the following paragraph. More information about photon activation analysis of industrial products can be found in R e f ' s . A summary of several applications

1076

~1079.

of photon activation analysis to industrial

and raw material i s given in T a b . 6 . 2 - 8 .

527

T a b . 6 . 2 - 8 : Instrumental photon activation analysis of raw materials and industrial products Bremsstr. Material

e n e r g y , MeV

Rev.

analysed

(Ιβ,μΑ)

Elements determined

Ref.

no.

Various metals

27 (50)

Ti, Ni, Zr, Ag

903

105

Bronze

70 (not

Eu, Gd

307

106

Copper ore

13.6 (not g i v e n )

Cu

1066

100

Various alloys

24 (not

Zr

1186

Various metals

35 (50)

Ni, T I , Pb

843

Noble Metals

1187

Ores and metals

given)

given)

5-40 ( v a r i a b l e )

107

Ores

25 (not g i v e n )

Nb, Ta

258

Ores

not given

Cu

256

Ores

9 (30)

Au

283

96

Ores

5 (700)

W

1067

103

Copper ore

15-26 (not

Ti, Mo, Rh

1164

97

As, Sr, Zr, Sb, Cs, Ce, Tm,

952

114

101

given) 35-45 (5-10)

Glass

TI Ores

14.9 (not g i v e n )

Cu

255, 1192

Rock samples,

14 (20)

A g , Au

291

not given

Na, Mg, Ca, T i ,

Cr, Mn, Fe,

Co, Ni, Rb, Sr,

Y, Zr,

ores Minerals,

ores

Ba, Ce

Nb,

1188

98

528 Tab.6.2-8,

continued Bremsstr.

Material

energy,MeV

analysed

(Ιβ,μΑ)

Elements determined

Ref.

no.

PVC

16 ( 2 0 - 3 0 )

Zn, Cd, B a , Pb

1075

113

Petroleum

35-40 ( 1 0 0 )

F , Pb

1189

11.9,

F, Κ

262

112

Rev.

products ΖτΟη

26.5

(not given) Various alloys

29.2 (35)

Ge, Zr, Nb, Mo

293

108

Platinum o r e ,

30 ( 1 5 0 )

Noble Metals

155, 1071,

109

copper

1072

Black C o n c e n t r .

6-8

Black C o n c e n t r .

35 ( 6 6 )

Br,

(70)

Rh, Ag, B a , I r , P t , Au

Rh, Pd, Ag, I r , P t , Au

102

1065

99

688

49

Coke

16, 30 ( 2 0 0 ,

Coal

30 ( 3 0 )

not clearly specified

1190

Coal

21 ( 5 )

Ca, Fe,

296

Ores

8 (1000)

Au

Phosphate r o c k ,

150) U

921

18, 30 ( 6 0 , 90)

Sr

290, 1191

Na, Mg, Cl, K, Ca, T i ,

Cr,

Μη, Fe, Co, Ni, Zn, As, S e ,

coal

Rb, Sr,

1068,

104

1073

110

Y, Zr, Nb, Mo, Cd,

S b , I , Cs, B a , Ce, P b , U Coal

up to 45 ( 5 0 )

111

Na, Mg, Ca, T i ,

C r , Mn, Fe,

Co, Ni, Zn, As, B r , Y, Z r , S b , I, B a ,

Rb,

Sr,

Ce, P b , U

1074

529

6.2.4.6

A n a l y s i s of a r c h a e o l o g i c a l material a n d f o r e n s i c a n a l y s i s

In t h i s p a r a g r a p h , only few works a r e r e v i e w e d since p h o t o n a c t i v a t i o n a n a l y s i s h a s been a p p l i e d to a r c h a e o m e t r y a n d f o r e n s i c s c i e n c e in v e r y few c a s e s a s y e t . Studying of

the

science

ing.

literature

one

about

activation

analysis

application

neutron

activation

will f i n d classical t h e r m a l

Furthermore,

a good deal of t h e i n s t r u m e n t a l p h o t o n

work in a r c h a e o m e t r y

to

these

clearly

fields

dominat-

activation

analysis

was p e r f o r m e d in the l a b o r a t o r y of t h e a u t h o r s of

this

book.

One special a d v a n t a g e of t h e method might become r e l e v a n t in a r c h a e o m e t r y a n d criminology, strict

namely

sense,

without

i.e.

the the

possibility analysis

of

t h e n e c e s s i t y of s a m p l i n g .

of

non-destructive

entire

objects

-

On t h e one h a n d ,

analysis

also

very

in

its

large

analysing large

very

ones

-

objects,

s a m p l i n g b e a r s t h e d a n g e r of n o n - r e p r e s e n t a t i v e n e s s a n d on t h e o t h e r h a n d it sometimes might c a u s e damage d e v a l u a t i n g t h e object u n d e r i n v e s t i g a t i o n . over,

using photon activation,

a f a i r l y homogeneous a c t i v a t i o n can be a c h i e v e d

in t h e most c a s e s w h e r e a s in o t h e r t e c h n i q u e s , or X-ray

More-

fluorescence analysis,

e . g . thermal neutron activation

f r e q u e n t l y only small p a r t i t i o n s of t h e object

a r e c o m p r i s e d which - a s in t h e c a s e of s a m p l i n g - might not be r e p r e s e n t a t i v e for

the

total.

Finally,

extremely

long-lived

p r o d u c e d in e x c e s s i v e a c t i v i t i e s t h r o u g h

radionuclides

photon activation.

generally Therefore,

are

not

objects

which had b e e n a c t i v a t e d with p h o t o n s may be r e t u r n e d in t h e collection o r e x p o s e d in t h e p u b l i c a f t e r a p p r e c i a b l y

s h o r t cooling time.

possible a f t e r e x p o s u r e to high f l u x t h e r m a l n e u t r o n s .

T h i s usually i s not

For i n s t a n c e ,

i n g s i l v e r o b j e c t s with p h o t o n s of s a y 20 MeV maximum e n e r g y , will be p r o d u c e d

which h a s a h a l f - l i f e of 8 . 3 d a y s .

in a n u c l e a r r e a c t o r ,

however,

mainly

I r r a d i a t i n g t h e same object

H " m A g will be t h e most p r o m i n e n t p r o d u c t

lide with a h a l f - l i f e of 250 d a y s , a b l y high r a d i o a c t i v i t y f o r y e a r s .

nuc-

a n d t h e r e b y t h e object may c o n t a i n c o n s i d e r However,

in s e v e r a l e x c e p t i o n a l c a s e s ,

problem also might a r i s e in photon a c t i v a t i o n a s was d e m o n s t r a t e d context by

irradiat-

in

this

another

Kuttemperoor245,1080.

In t h i s p a r a g r a p h ,

p u b l i c a t i o n s a b o u t t h e a p p l i c a t i o n of p h o t o n a c t i v a t i o n

l y s i s to a r t a n d a r c h a e o l o g y ation s t u d i e s a r e

discussed.

are reviewed

first,

ana-

and t h e n f o r e n s i c p h o t o a c t i v -

530

- A r t and archaeology According

to the literature accessible to the authors,

photon activation analy-

sis as applied in archaeological science was exclusively of

metals and

interest,

e.g.

ceramic

material up till now.

Other

glasses,

dyes and organic matter,

used f o r the analysis

materials of

have,

archaeological

as f a r as the authors

know, not yet been studied using photoactivation.

Among all archaeological materials pottery has been studied most since it was used in large quantities in all ancient cultural spheres and thus it is a good indicator

for

many

questions

the life time of ordinary tively

of

archaeological

relevance.

Furthermore,

household pottery objects usually has been

since

compara-

short they have been reproduced in large series and therefore a lot of

pottery fragments have been available to scientists f o r contemporary and research.

Pottery

material - at least

the

fine

reference

ware - may be considered

fairly homogeneous within one specimen (Knoll et a l . 1 " ® * ) . It has been demonstrated

that a sample of

Roman

Red

Ware

(terra

not less sigillata)

than about normally

50 milligrams taken represents

accurately - as f a r as the elemental composition is concerned. tional cases one

might

find

slight

from ancient

the entire object

quite

In a few excep-

differences in the elemental

concentrations

between the surface area and the bulk of a pottery sherd, e . g . caused by e n v i r onmental influence Lemoine

during

et al.

authors'

long-term

However,

laboratory,

burial

during

a surprisingly

(Segebade

studies

of

homogeneous

and Lutz*"'®· 1082-1084^

coarse ceramic ware in the distribution

of the

elements

throughout an entire specimen was stated. In this case larger samples had to be taken because of the coarse grain structure of the material under study. The analysis of metal objects entails essentially gin at the sampling stage. ferent

reasons

might

which

be-

Possibly significant inhomogeneities caused by

dif-

have to be considered.

different

First,

problems

metal objects might

have

been assembled by the producer using parts of differently composed metals, e . g . in order to achieve decorative variations of the colour.

Instead,

pottery

spe-

cimens normally have been produced using one batch of clay material and then eventually have been painted.

Inhomogeneities of metal objects also might occur during the different processing ents.

steps of

the metal alloy,

Furthermore,

fluence,

e.g.

e.g.

segregation

behaviour of certain

compon-

the surface area composition might be altered by outer in-

long-term

handling.

This particularly applies to ancient

as is demonstrated in several papers reviewed below. T h e r e f o r e ,

coinage

representative

531

sampling from metal o b j e c t s might become e x t r e m e l y

difficult compared with t h e

sampling of p o t t e r y . Furthermore,

t h e matrix compositions of d i f f e r e n t kinds of p o t t e r y normally a r e

quite

in

similar

advantage

to c e r t a i n

cultural

analytical

task,

spheres

in t h e m a t e r i a l .

or

it might

e.g.

cannot

be

instrumental

techniques,

standardised

large

series

of m e t a l - b a s e d

multielement

single

reference

t e r y a n a l y s i s ( s e e also p a r a g r a p h 6 . 2 . 2 ) . will s t r i v e

to use more than

different

In p r a c t i c e ,

multielement

difference

between

a l r e a d y touched on a b o v e ; without a n y r e s t r i c t i o n , mens, sons

particularly

pottery

(homogeneity,

and

can

to

the

used

whereas for

pot-

For i n s t a n c e ,

have

metals

concerning

been

in

used

their analysis

from p o t t e r y

Therefore,

in

was

specimens speci-

for t h i s and o t h e r

rea-

t h e n o n - d e s t r u c t i v e a n a l y s i s might be r e q u i r e d I n s t r u m e n t a l photon activation

different

chemical

analy-

for t h e n o n - d e s t r u c t i v e

sis of metal specimens as was mentioned in t h e i n t r o d u c t o r y due

be

however, the experienced

materials

sis has proven to o f f e r c o n s i d e r a b l e a d v a n t a g e s Finally,

materials

not be allowed in the c a s e of metal

in t h e c a s e o f metal matrix u n d e r s t u d y .

ter.

fre-

(Sayre^"8®).

metal o b j e c t s .

see a b o v e ) ,

reference

material.

whilst samples can be taken

t h i s might

precious

Hence,

and

National L a b o r a t o r y in Long I s l a n d ,

reference

r o u t i n e p o t t e r y neutron activation a n a l y s i s

Another

possible

- are required

material

one r e f e r e n c e

t h e a r c h a e o m e t r y section of t h e B r o o k h a v e n six

is

of

T h u s in photon activation a n a l y s i s as in most

theoretically

U.S.A.,

or a s s i g n m e n t of t h e

which

b a s i c metal to be i n v e s t i g a t e d

one

of

T h e elemental composition

- a t l e a s t one for each

analyst

is s u r e l y

be a d i s a d v a n t a g e for t h e

classification

producers.

This

h o w e v e r , might d i f f e r by s e v e r a l o r d e r s of m a g n i t u d e .

procedure

q u e n t l y done in ceramics s t u d i e s . other

present

work although

part of t h e given

metal s p e c i m e n s , the

of elements

for t h e a n a l y s t ' s

archaeological object

terms

behaviours

analy-

part of t h i s

(e.g.

chap-

solubility)

of

metals and p o t t e r y , metals f r e q u e n t l y have been studied using d e s t r u c t i v e t e c h niques,

e.g.

wet

chemistry,

atomic a b s o r p t i o n

spectrometry,

atomic

emission

s p e c t r o m e t r y and o t h e r s , whereas p o t t e r y almost i n v a r i a b l y has been a n a l y s e d by instrumental radiometric t e c h n i q u e s , lysis, The

e.g.

X - r a y f l u o r e s c e n c e or activation

from t h e time of t h e i r g e n e r a l availability publications

classes

studied

reviewed as

is

done

in in

the the

following other

are

not

application

r o u g h c h r o n o l o g i c a l o r d e r of t h e i r a p p e a r a n c e .

ana-

hitherto. ordered

by

the

subparagraphs

material but

in

a

532 115) Undoubtedly, the f i r s t application of photon activation to archaeology was r e p o r t e d by Voigt and Abu-Samra'"'^. T h e y analysed carbon in a Damascene steel 19 IT sword using t h e reaction l i C ( y , n ) C. This work is not reviewed here since it i s concerned with the analysis of a light element and t h e r e f o r e is discussed in t h e preceding section about photon activation analysis of t h e light elements. 116) In a p a p e r of Thompson and Lutz*®®^ an instrumental photon activation a n a lysis p r o c e d u r e is described with help of which ancient bronze a r t i f a c t s were analysed.

This work was carried out within a comparative analytical s t u d y in

which many laboratories participated using d i f f e r e n t analytical t e c h n i q u e s . samples lay b e f o r e as fine c h i p s .

10-20 mg batches

The

were wrapped into thin

plastic foils and encapsulated in polyethylene r a b b i t s . An NBS r e f e r e n c e bronze was used as multielement r e f e r e n c e material. 30 MeV b r e m s s t r a h l u n g was used f o r activation. The samples were irradiated for approximately one h o u r . A f t e r i r radiation, t h e samples and r e f e r e n c e materials were dissolved in HNOg/HF mixt u r e and diluted to a s t a n d a r d volume to provide a reproducible counting geom e t r y . G e ( L i ) - d e t e e t o r s with 47 and 60 cm^ active volume were used f o r gamma spectrometry.

The copper content of the samples and r e f e r e n c e materials was

used as an i n t e r n a l flux monitor selecting the induced ^ C u a c t i v i t y . The c o p p e r concentration of the samples had been determined previously using thermal n e u t r o n activation analysis. Fe, Ni, Zn, Sn and Pb were analysed, but only for tin

and

lead

definite r e s u l t s

could

be given

since the concentration

of the

o t h e r elements were below the experimental detecion limits (about 0 . 1 %). For tin comparative values were available which were obtained with help of i n s t r u mental neutron activation analysis in the same laboratory;

the agreement was

fairly good. 117)

Segebade

et

al. 1 5 6 , 1082-1084,1088

ancient Roman p o t t e r y .

made

iarge-scale

investigations

on

Studying various a s p e c t s concerning this material, the

analytical p r o c e d u r e was virtually the same in each of t h e above cited works. 50-200 mg b a t c h e s of the pulverised material were taken and wrapped in aluminium foil. Depending upon t h e number of t h e available gamma s p e c t r o m e t e r s , s e t s of several samples were irradiated simultaneously for 2-6 hours with 30 MeV b r e m s s t r a h l u n g at 150 microamperes mean electron beam c u r r e n t . A s t a n d a r d clay served

as multielement

r e f e r e n c e material

(Knoll et al. 1^81). A f t e r i r r a d i a t -

ion, the samples were mixed with about 200 milligrams of cellulose powder and p r e s s e d into l a r g e , thin pellets. Each sample was measured several times a f t e r i n c r e a s i n g cooling periods. Both gamma-ray spectrometry and low e n e r g y photon measurement were used for activity c o u n t i n g . With t h i s p r o c e d u r e , the following 27 elements could be a n a l y s e d : Na, Mg, Si, K, Ca, Sc, Ti, Cr, Μη, Fe, Co, Ni,

533 Zn, As, Se, Rb, Sr, Y, Zr, Nb, Sn, Sb, Cs, Ba, Ce, Pb and U. The accuracy of some of t h e obtained data was checked by an i n t e r l a b o r a t o r y Round Robin a n a l y s is of a similar material, using X-ray fluorescence analysis, instrumental n e u t r o n - and photon activation and 14 MeV neutron activation. The comparison of t h e r e s u l t s yielded good agreement of the photon activation data with those o b t a i n ed by the o t h e r methods. 118) The analysis of precious metal coins and a silver vase as r e p o r t e d Reimers et

al.

884.1180

by

had

to be carried out n o n - d e s t r u c t i v e l y for the reasons mentioned in the i n t r o d u c t o r y p a r t of this p a r a g r a p h .

Copper, silver and gold

were analysed in the coins, and gold in the silver vase using activation with 30 and 15 MeV b r e m s s t r a h l u n g and s u b s e q u e n t gamma-ray spectrometry with a Ge(Li)-detector.

During this work, several problems had to be solved.

First,

f o r most of the specimens, no adequate r e f e r e n c e material was available. Using an e x t e r n a l flux monitor, small discs of the p u r e elements to be analysed could s e r v e as s t a n d a r d s . Second, self-absorption d u r i n g gamma spectroscopy had to be c o n s i d e r e d . Since gamma-ray lines of high energies ( g r e a t e r than 1000 keV) were used for analysis, this correction could be performed quite easily and

accur-

a t e l y . T h i r d , the i n t e g r a l matrix activity had to be kept as low as possible so t h a t the objects could be r e t u r n e d into the collection quasi-immediately a f t e r analysis. This was accomplished by holding the activating photon flux as low as the r e q u i r e d sensitivity allowed. T h e r e f o r e , t r a c e components could not be a n a lysed,

but t h e i r determination was not r e q u i r e d in this case. Finally, a s p e c -

t r a l i n t e r f e r e n c e had to be eliminated:

^"^Ag, produced t h r o u g h

^^AgCy.to)

emits a gamma-ray line which partly overlaps the peak used for gold analysis. This i n t e r f e r e n c e is significant

in the analysis of less than

1% of gold

in

silver matrix. A gold concentration beneath this level was expected to be p r e sent in the v a s e . T h e r e f o r e , the object was irradiated with 15 MeV b r e m s s t r a h l ung to avoid the i n t e r f e r i n g silver reaction which has a threshold e n e r g y above 15 MeV. Whilst the coins could be measured readily a f t e r activation, the measurement of t h e vase had to be performed with a modified p r o c e d u r e . A small spot within the activated area of the object was screened out with a lead collimator fixed to the detector housing. For one set of the analysed coins,

comparative

analysis r e s u l t s obtained by 14 MeV neutron activation analysis lay b e f o r e . The agreement

was satisfactory except for several copper values; the copper was

r a t h e r low-concentrated in the coins and t h e r e f o r e , t h e analysis had to be c a r ried out close to the experimental detection limit. The accuracy of the concentration data for the o t h e r set of coins could only be estimated by summing up the obtained values and checking the d i f f e r e n c e to 100% since no comparative data were available. The largest d i f f e r e n c e to 100% was 2.8%. Hence, with r e -

534

spect to the precision requirements,

the quality of these values could also be

considered s a t i s f a c t o r y . However, t h e r e was no possibility to check the quality of the r e s u l t s f o r the silver v a s e . In

this work,

several a d v a n t a g e s

were demonstrated;

of instrumental

photon activation

analysis of gold matrix in using o t h e r analysis methods, n e u t r o n activation (Sayre* 0 ® 9 , 119)

Neider et al.

particularly

thermal

Meijers* 0 9 ").

The comparison of r e s u l t s of ancient

large-scale

analysis

several difficulties could be avoided as they arise in the

bronze analyses

was reported

by

This work was performed within the preliminary studies of a

investigation

work

about

medieval bronze

objects.

Small samples

(10-50 mg) were drilled out of the objects (fountain decorations) and

irrad-

iated f o r 1-4 h o u r s with 30 MeV b r e m s s t r a h l u n g (mean electron beam c u r r e n t : 150 microamperes). The resulting gamma radiation was measured several times a f t e r d i f f e r e n t cooling periods with a 50 cm^ G e ( L i ) - d e t e c t o r .

A certified

standard

bronze was used as a multielement r e f e r e n c e material. Fe, Ni, Cu, Zn, As, Ag, Sn, Sb and Pb were analysed both by instrumental photon activation analysis as described and also by atomic absorption s p e c t r o m e t r y . The comparison showed s a t i s f a c t o r y agreement in the most cases. 120) The r e s u l t s of a comparison s t u d y on d i f f e r e n t analytical techniques a p plied to the analysis of ancient Roman b r a s s coins p e r h a p s elucidates the d i f ficulties of sampling in ancient coinage studies

( C a r t e r et al. 1091.

see

ajso

R e f . 1 0 9 2 ) . In t h e photon activation analysis p r o c e d u r e , the samples were i r r a d iated

as such

without any treatment

before or a f t e r activation

with 30 MeV

b r e m s s t r a h l u n g . The e x p o s u r e periods v a r i e d , depending upon the mass of the samples (400 mg to 5 g ) , between 1 and 3 h o u r s . A f t e r a cooling period of about five d a y s ,

the

activity originating from copper which was p r e s e n t in the

matrix at 70-80% had decayed to negligible level, measurements were performed with both a l a r g e volume coaxial Ge(Li)-detector and a small planar low e n e r g y photon diode. element

Standard b r o n z e s ,

concentrations

b r a s s e s and copper specimens with certified

were used as multi-element

r e f e r e n c e materials.

none of them were available with a shape similar to the analysed

Since

fragments

(roughly a q u a r t e r - c i r c l e being about 1 mm thick) the matrix copper was used as an i n t e r n a l flux monitor. In the f r a g m e n t s , the copper content had been d e t e r m ined previously by wet chemistry analysis ( g r a v i m e t r y ) . These values were considered

most reliable compared with the r e s u l t s of instrumental methods.

Cr,

Μη, Ni, Zn, Ge, As, Se, Ag, Sn, Sb, Te, Au, Tl, Pb, Bi and U were analysed by instrumental photon activation analysis; out of these, Ni, Zn, Ag, Sn, Sb and

535

Pb were included in the intercomparison p r o c e d u r e . The applied methods in the intercomparison s t u d y were: wet chemistry, w a v e l e n g t h - d i s p e r s i v e X-ray f l u o r escence s p e c t r o m e t r y , cence analysis,

tube-excitation source e n e r g y - d i s p e r s i v e X-ray f l u o r e s -

radionuclide excitation

escence analysis,

atomic absorption

photon activation analysis. prised

the

entire

source e n e r g y - d i s p e r s i v e X-ray f l u o r -

spectrometry,

instrumental

neutron-

and

Among these only photon activation analysis com-

sample whereas

all o t h e r s

could

only

analyse

greater

or

smaller subsamples of i t . Hence, some of t h e disagreements between the obtained r e s u l t s surely

a r e due

to inhomogeneities in the material (Caley*®®"*) which

were also detected d u r i n g microstructural studies of the o b j e c t s . However,

in

general - with a few exceptions - the agreement of the photon activation a n a l y sis

results

good.

with

the consensus

It became evident

values

calculated

from all obtained data was

that none of the participating

methods outstood

all

o t h e r s in e v e r y relevant aspect; the particular a d v a n t a g e of instrumental photon activation analysis as performed in t h e described case is its analysing the e n t i r e o b j e c t . However, in several disadvantageous cases, this does not g u a r a n tee usable and r e p r e s e n t a t i v e analytical r e s u l t s . 121) Ancient Roman copper coins were analysed using i n s t r u m e n t a l photon a c t i v ation analysis and wavelength-dispersive X-ray fluorescence analysis as r e p o r t ed by Segebade et a l . 1 0 9 4 .

The activation analysis p r o c e d u r e was essentially

the same as applied in the work on the b r a s s coins reviewed above. However, h i g h - e n e r g y gamma spectrometry was used only, and the coins were counted f i r s t a f t e r a w e e k ' s decay period and then once more a f t e r 20 d a y s . Two d i f f e r e n t reactions of the matrix copper were used for i n t e r n a l flux monitoring,

namely,

in t h e f i r s t measurement ®^Cu(y,n) yielding ® 4 Cu, and in the second measurement an)^®Co since a f t e r the second cooling period ®4Cu had decayed to n o n detectable a c t i v i t y . Mn, Fe, Ni, Zn, As, Se, Ag, Sn, Sb, Te, Au, Pb and U were analysed by photon activation. The agreement with the comparative X-ray f l u o r escence values covered a wide r a n g e from "very bad" to "excellent". In t h e work reviewed above about t h e b r a s s coins (Rev.120) the specimens were sacrificed by c u t t i n g them into suitably-sized pieces which were then abraded and polished to create

optimal

conditions

for X-ray

fluorescence s p e c t r o m e t r y .

Thereby

one

could assume a s u r f a c e r e p r e s e n t i n g a fairly good cross section of the bulk material. The copper coins, however, were analysed a s such without any p r e treatment exceeding a careful mechanical removal of o u t e r s u r f a c e contaminants. Thus,

the topographies of the coins were inconstant and the conditions for X-

ray fluorescence were not optimal. This might partly explain the disagreements between some of the r e s u l t s obtained by both methods.

536 122) Going out from these r e s u l t s , Segebade and Carter*095 undertook systematic s t u d i e s about

the macroscopic homogeneities of several of these coins,

using

i n s t r u m e n t a l photon activation analysis. No absolute concentrations of compone n t s were analysed,

but relative areal distributions of Ag, Au, Pb and Bi.

T h e r e f o r e , no r e f e r e n c e material was needed. The coins were irradiated f o r six h o u r s with 30 MeV b r e m s s t r a h l u n g at 150 microamperes mean electron beam c u r r e n t . A f t e r seven days decay time t h e coins were scanned two-dimensionally in f r o n t of a G e ( L i ) - d e t e c t o r .

This detector was equipped with a lead collimator

which screened out a small spot of t h e coin s u r f a c e . Since an a p p a r e n t

mass

determination

very

of

the

analysed

partition

was not

practical

(due

to the

i r r e g u l a r t o p o g r a p h y of the objects) the obtained activities were normalised by the

58

Co activity produced in the matrix (see a b o v e ) . As a r e s u l t , the Noble

Metals a p p e a r e d to be d i s t r i b u t e d v e r y homogeneously,

whereas locations with

abnormously high bismuth concentrations were found d i s t r i b u t e d i r r e g u l a r l y over the coins, and lead showed a pronounced concentration gradient a c r o s s the total coin b o d y . 123) The work reviewed next combines both fields of science discussed in this paragraph,

namely archaeometry and f o r e n s i c science. Lead and copper in tin

v e s s e l s were analysed using instrumental photon activation analysis (Segebade, Ref.*"®®). T h e s e vessels were offered for sale and declared as late medieval works or as produced shortly t h e r e a f t e r . By stylistical check some of them were s u s p e c t e d to be recent f o r g e r i e s . Studying medieval regulations concerning the purity

requirements

of

the

basic

c o p p e r appeared

to be useful

these

expected

data

were

stylistical investigations.

material,

fingerprints

to s e r v e

the

concentrations

of lead

for genuinity assessment;

as additional indicators

along

Samples of 50-200 milligrams were taken

of the twenty objects u n d e r s t u d y . The o t h e r s were analysed

and

at least with

the

from most

non-destructively

as also performed in the above discussed analysis of a siver vase reported by Reimers et al.®®^·^®"; see Rev.118. The irradiations were conducted with an electron linear accelerator using 30 MeV electron e n e r g y at 150 microamperes mean electron beam c u r r e n t . The a v e r a g e e x p o s u r e time was one h o u r , in the case of n o n - d e s t r u c t i v e analysis 2.5 h o u r s since the objects had to be removed from the beam c o n v e r t e r to comprise a large area of t h e specimens. Gamma measurements were c a r r i e d out with a s t a n d a r d Ge(Li) s p e c t r o m e t e r . The copper concentrations r a n g e d between 0.1 and 1%, and lead between 0.5 and 7%. The p a r t i c u l a r problem in this case was due to the tin matrix. The resulting s p e c t r a were e x tremely complex because of the large number of photonuclear reactions of tin (see C h . 5 ) . Due to the relatively high concentrations to be analysed,

instru-

mental photon activation analysis could be applied in t h i s case, but for e v e n t -

537 ual trace analyses in tin matrix one would either have to insert a chemical separation step into the analysis p r o c e d u r e or a n o t h e r technique would be the method of choice, e . g . neutron activation analysis. As a r e s u l t ,

several of the objects could

since the concentrations and

lead) did

essentially

be clearly identified as f o r g e r i e s

of the major c o n s t i t u e n t s of the alloy (tin,

copper

d i f f e r from the material compositions indicated

by

the hallmarks imprinted on the vessels. - Forensic analyses Photon activation analysis has been applied least to forensic science as

yet.

However, it is an i n t e r e s t i n g fact that photoactivation of heavier elements was one of the f i r s t to be applied - if not t h e v e r y f i r s t - to crime detection. 124) As early a s 1964, Bryan et a l . using bremsstrahlung

activation.

analysed lead in moonshine whiskey It is f u r t h e r l y i n t e r e s t i n g to note that

this

pioneer work was performed without any sample treatment prior to or a f t e r i r radiation. The samples were irradiated with 25 MeV b r e m s s t r a h l u n g of a 45 MeV electron linear accelerator for one h o u r . A f t e r a cooling period of about t h r e e d a y s they were counted f o r ten minutes with a Nal s p e c t r o m e t e r . Parallel colorimetric analyses were also carried o u t . The agreement of the r e s u l t s was a c c e p t a b l e . See also R e f . 1 0 9 9 . In the same p a p e r ,

the photon activation analysis of glass samples, also c a r -

ried out p u r e l y instrumentally, was r e p o r t e d . Ten d i f f e r e n t samples of automobile

glasses

(lights,

windshields

etc.)

were irradiated

and

a f t e r several decay periods with a scintillation s p e c t r o m e t e r .

counted

multiply

Because of the

multiple peak overlap i n t e r f e r e n c e s in the complex resulting s p e c t r a , no a b s o lute

quantitative

analysis

was attempted,

but

glass

samples

source could be clearly identified by the gamma spectrum

from the

same

pattern.

In the analysis of glass matrix, photon activation is s u p e r i o r to neutron a c t ivation because of the usually high sodium content of glass. In a n o t h e r r e p o r t of this group ( S e t t l e ^ ® " ) ,

the glass analysis p r o c e d u r e used was described in

somewhat more detail. See also R e f ' s . HOI·· 1102t 125) According to the a u t h o r s ' knowledge, t h e r e was no f u r t h e r application of photon activation to forensic analysis published until 1980 when Kanda et a l . , Ref.H03 >

a

jso

rep0rted

the analysis of glass samples in forensic context ( h i t -

538

and-run resolution

cases in t r a f f i c accidents).

The suitability of the method using

high

gamma spectrometry was examined analysing an NBS reference glass

sample. A multi-element reference material was prepared b y adding known amounts of compounds of the desired elements to a synthetic glass matrix. The samples were powdered,

wrapped into aluminium foil and pelletised.

Samples and r e f e r -

ence materials were sandwiched and then sealed in a silica tube. The irradiation was conducted with 30 MeV bremsstrahlung at 100 microamperes mean electron beam current. A f t e r irradiation, the samples were repacked and counted several times after increasing cooling periods with standard G e ( L i ) spectrometers.

Na,

Mg, Ca, Sc, T i , Μη, Co, Ni, A s , Rb, Sr, Y , Zr, Nb, Sb, Cs and Ce were analysed. The reported sensitivities were between 400 ng/g ( f o r Y and Cs) and 0.035% ( f o r Ca).

As far as certified NBS-values or other comparative data were available,

good agreement was stated.

In T a b . 6 . 2 - 9 , a summary of papers about photon activation analysis in archaeology and forensic science is presented.

539

T a b . 6. 2-9: Instrumental photon activation a n a l y s i s of a r c h a e o l o g i c a l and f o r e n s i c material

Bremsstr. Material

e n e r g y , MeV

analysed

(Ιβ,μΑ)

Bronze

30 ( n o t

Pottery

30 ( 1 5 0 )

N o b l e Metal

Rev. Elements determined

given)

Ni,

Fe,

Zn,

Sn, P b

Ca,

Sc, T i ,

Ref.

no.

1087

116

156,

117

Na, M b .

Si,

K,

Cr,

Mn,

Fe,

Co,, Ni, Zn, A s ,

1081-1084,

Se,

Rb,

Sr,

Y, Zr,

1088

Sb,

Cs,

Ba,

Ce,. Pb,, u

15, 30 ( 1 5 0 )

Cu,

Ag,

Au

30 ( 1 5 0 )

Fe,

Ni,

N b , Sn,

884, 1180

118

A g , , Sn,

58

119

As,,

1091

120

1094

121

1095

122

objects

Bronze

Cu, Zn, A s ,

Sb, Pb

Brass coins

30 ( 1 5 0 )

Cr,

Mn, Ni,

Ag,

Sn,

Bi,

C o p p e r coins

30 ( 1 5 0 )

Zn,

Sb, T e ,

Ge, Au ,

Se,

Tl ,

Pb,

U

Mn, Fe,

Ni,

Zn,

Sn,

Sb, T e ,

A u , , P b , Bi

Au ,

As, Pb .

Se,

Ag,

u

C o p p e r coins

30 ( 1 5 0 )

Ag,

Tin objects

30 ( 1 5 0 )

Cu, P b

1096

123

Whisky

25 ( 5 0 0 )

Pb

1097

124

Glass

25 (500)

Na, Zn, (Nb ,

Glass

30 ( 1 0 0 )

Sb,

Sr,

Y, Zr,

Sn

1100

Mo)

Na, Mg, Ni,

As,

As, Cs,

Ca, Rb, Ce

Sc,, T i , Mn,, Sr,

Y, Zr,

Co

Nb,

1103

125

540 6.2.4.7

Comparison studies; analysis of reference materials

T h e r e are not too many papers to be found in the literature which deal whith the

analysis

of

reference

materials

or

intercomparison

mostly these are performed along with other analyses.

studies

exclusively;

Therefore,

most of the

publications discussed in this paragraph are reviewed in other context in the preceding paragraphs or in the following final one. At this point the

results

of the comparison with either certified or recommended data or results of other analyses of the same material are presented only and the reader may find more detail on the scientific background and the analysis procedure in the c o n c e r n ing paragraphs. Studying

the

literature

one can

differentiate

roughly

between

four

material

classes analysed by instrumental analysis for comparison studies. F i r s t , ashes,

dusts and related matter, second, metal-based material, third,

based material and

finally,

glasses.

Since several specific reference

rocks,

organicmaterials

( e . g NBS-SRM) have been analysed by many working groups it is practical to combine these r e s u l t s . Since every experienced analyst uses certified multielement reference materials, either exclusively or as secondary standard, many comparative data obtained by instrumental photon activation analysis and other t e c h niques can be found in the application section of this book. In this paragraph, only a few examples were given to demonstrate accuracy and precision achievable in instrumental

photon activation

use are focussed,

analysis.

Moreover,

materials of widespread

so as to supply the reader of this book with concentration

data of many components in these specimens which are not given by the producer, be it as certified or recommended values. On reviewing the literature, it appears that within the material category named first ( r o c k s , ashes e t c . ) fly ash was studied most, particularly the N B S - r e f e r ence

coal fly

stock, analyst;

ash

(NBS-SRM

hence the concentration nontheless,

1633).

Unfortunately,

this

material ran out

of

data might be of limited practical use for the

the comparison

elucidates the quality of photon

activat-

ion analysis r e s u l t s . In the following tables,

all concentration

values are given in micrograms per

gram unless stated otherwise. In the leading explanatory paragraph, the sources of the data presented in the table are given,

followed eventually by several remarks about these sources or

the concerned material.

541 - Analysis of NBS-SRM 1633 (coal fly ash) Explanations to T a b . 6 . 2-10: a - Certified or recommended (in b r a c k e t s ) values b - Chattopadhyay and J e r v i s 8 8 3 c - Paciga et a l . 1 1 0 4 d - Chattopadhyay and J e r v i s * 1 · 0 5 e - Roberts et a l . 9 7 5 f - Ündov et

a

l.1002'1003

g - Kato et a l . 9 1 9 h - Kato et a l . 9 5 6 i -

Chattopadhyay330

j - idem, photon a c t i v a t i o n " " " I

M

k - idem, neutron activation 1 - J e r v i s et a l . 1 0 1 8 m - Segebade et a l . 1 5 7 η - Segebade and Fusban® 8 8 Another compilation of comparative concentration values obtained from the analysis of coal fly ash (BCR No. 38) using various methods including photon a c t i v ation analysis can be found in R e f . * * 9 ® ; see a l s o * * 0 7 . This report contains the results of a certification campaign initiated by the European Community R e f e r ence Bureau

(BCR).

542 T a b . 6 . 2 - 1 0 ; v a l u e s given in vig/g u n l e s s s t a t e d K.h

i. j . l

k

3860±130

3300±150

3200±300

—

1.50±0.01

1.50±0.15

1.68±0.21

—

—

21—2

—

20±1.6

—

—

19.6±0.1

—

—

25Ϊ7

32±10

—

El. a

b,c,d,e

Na

—

3400±300

Mg%

—

1.48±0.01

Si% C1

— —

f

m

—

—

1.59±0.05

1.60±0.06

1.69±0.13

—

Ca%

—

3.92±0.28

5. 3—0. 5

5.1±0.03

4.4±0.4

4.5±0.5

—

Sc

—

20.7±?

—

—

27±2

25. 5^2

—

K%

(1.72)

Ti

—

7320±40

7300Ϊ300

7660±70

7250±360

7300±280

—

V

214±8

208±12

—

—

210±12

220±15

—

Cr

131±2

131±6.1

—

142±9

131±6

135±6

—

Mn

493±7

495±25

—

491±10

495±15

500±15

—

6.08±0.52

—

4.24±0.19

6.1±0.2

6.2±0.4

—

Fe% 6.14±0. 01 Co

(38)

35.4-2.8

—

42±3

40±2

42±1.6

—

Ni

98±3

96.8±3.2

92±6

96±3

97±5

95±9

100±7

—

—

—

—

140±20

Cu

128±5

—

Zn

210±20

214±16

216±25

—

215±20

200±20

205±20

As

61±6

60.7±2.6

61.5±3.0

65±1

60±2.6

59±4

63±4

Se

9.4Ϊ0. 5

9.48±0.8

—

—

9.5±0.8

9.8±1

10.0±0.9

Br

—

—

—

~

11.2±3.5

—

—

125±10

95±1

120±10

116±10

— —

Rb

(112)

Sr

(1380)

1373Ϊ95

—

1244±6

1370±120

1500±180

Y

—

—

62il0

67±1

60±8

~

—

Zr

—

301-22

301±20

298±6

300±20

310±20

—

Mo

—

1.52±0.15

—

—

0.5±0.08

—

—

—

7Ga is usable and fairly sensitive but the gamma an

spectrum is i n t e r f e r e d by al.60'158'159,

Cu produced through zinc activation (Segebade et

Rev.54, Schmitt et a l . 9 8 4 , Rev.50, Fusban et a l . 9 8 2 , R e v . 4 4 ) . In

these works correction

routines were used to account for the named i n t e r f e r -

ence. If

gallium is present in high concentrations,

e . g . in semiconductor material, a

79

source of multiple interference might be

Ga produced through activation with

photoneutrons. This nuclide emits a v e r y complex gamma-ray spectrum. However, this interference can be ruled out by cadmium shielding. Germanium

The analysis of germanium using 1107 keV from ®9Ge frequently s u f f e r s from the close neighbourhood of the 1116 keV peak from ®®Zn produced by zinc. The sensitivity

achievable

photon

diode is fairly

using

the Ga kX-ray

emission measured with a low

energy

good but the evaluation is somewhat problematic

the radiation is emitted

both by

®9Ge

and by ^ G e and therefore,

since

the decay

function of the common X-ray line is complex.

Oka et a l . 9 " 7 ,

Rev.5,

proposed to use

75mGe

( h a l f - l i f e : 48 s ) after short i r -

radiation periods. A b e l l 4 4 analysed germanium in germanium-titanium oxide mixtures long

using cooling

the

511 keV

periods

annihilation

so that

virtually

radiation all

due to

possibly

6 9 Ge

after sufficiently

interfering

activities

had

decayed to negligible level. Germanium, if present in large amounts, e . g . in semiconductor material,

pro-

581

duces an extremely complex gamma-ray background spectrum and thus might i n t e r f e r e with the signals of many trace components to be analysed. In this case the use of low e n e r g y photon spectrometry is recommendable.

Arsenic Arsenic can well be analysed by the 596 keV gamma-ray line of ^ A s . this line is partly overlapped by 593 keV of

43K

Frequently

produced by calcium. In the

authors' laboratory, a correction routine using other gamma energies of been successfully applied. The next abundant gamma-ray line of

75As

43K

has

(635 k e V )

normally is not seriously interfered, but is much less intense than the 596 keV line, so that the achievable sensitivity might be insufficient.

Chattopadhyay and J e r v i s 8 " 3 , Rev.40, reported interference from ^®Se(y,np) and Se77(^,nt) but found it negligible. Chattopadhyay 3 3 " ruled out the interference due to « κ

by allowing this nuclide to cool to quasi-zero activity (decay

iod: 14 d).Galatanu and by ^ Β Κ γ , β η ) .

Engelmann1®®®,

Rev.104, found first order interference

This might gain importance in the analysis of air dust because

of the automotive bromine exhaust

(Aras et a l . R e v . 3 1 ) .

reported interference by the 597 keV-line of in airdust

per-

6 2 Zn

Aras et al. also

produced by ® 4 Ζ η ( γ , 2 η ) . Since

zinc usually is one of the major constituents this interference has

to be paid attention to. Aras et al. proposed a long decay period to avoid the mentioned peak o v e r l a p .

Arsenic,

if

present

in larger

concentrations,

produces an intense

long-lived

background a c t i v i t y . Selenium Either ^ S e produced through photoneutron reaction or ^ m S e produced through isomeric state photoexcitation has been used mostly f o r selenium analysis.

The

analytical sensitivity is fairly good but the most abundant gamma-ray e n e r g y of 75Se

(265

keV)

is

interfered

by

several

other

radionuclides.

Galatanu

and

Engelmann 1 "® 8 ' 1073^ R e v ' s . 104,110, r e s p e c t i v e l y ) therefore measured this nuclide after a long

(up to 60 d ) cooling period.

In the authors' laboratory, 136

keV emitted by ^ S e has been used f o r analysis. Low energy photon spectroscopy has been applied.

In the case of excessive nickel concentrations present in the

samples the gamma-ray overlap from (Segebade et emitted by

al.159).

81mSe

57Co

has to be considered and accounted f o r

Chattopadhyay and J e r v i s 3 3 0 , 8 8 3 ,

Rev.40,

used 103 keV

and did not detect any interference. Using short irradiation

582

periods,

77mSe

has frequently been utilised for analysis. This nuclide has been

produced either by photoneutron reaction (Oka et al. 9 ® 7 , R e v . 5 ) or by isomeric state

photoexcitation

(Veres1®0, (Boivin

using

Rev.78,

et a l . 1 1 6 ,

Veres

either and

radionuclide

Pavlicsek 1 8 ®)

Lukens et a l . 1 2 1 , 1 2 4 ,

sources,

or

especially

accelerator

R e v ' s . 23 and

24,

®°Co

bremsstrahlung

respectively,

and

many o t h e r s ) . The high e n e r g y (6.14 and 7.11 MeV) gamma radiation of reactorproduced

has been used f o r isomeric state formation by Akbarov et a l . 1 9 5 .

This method is interesting since higher activity yields can be expected due to the higher exciting e n e r g y , experimental

but because of the short half-life of

difficulties have

to be taken

possible to perform an in-situ activation

into account.

through

(7.4 s)

However,

it may be

a suitable secondary

target

( e . g . o x y g e n ) with help of accelerator-generated fast neutrons. As yet no r e port about such an application has been available to the authors.

If

the

but -

photoexcitation

method is used

the analysis is free

due to the short half-life of the activation product Dams® 24 ,

a special analysis procedure.

from

interference

(17.5 s ) -

Rev.29) reported the use of

requires

79mSe

for

analysis after activation with 25 MeV bremsstrahlung. Selenium, if present as a major or minor component, emits a v e r y complex gammaray

spectrum

after

high

energy

activation

and thus

may cause

interference

during analysis of other elements, especially traces. Selenium

might

be

subject

to volatilisation

bound (see above, 6 . 2 . 4 . 3 ) .

losses,

Chattopadhyay 1 " 1 ®,

particularly

if

organically

Rev.62, stated selenium losses

of up to 30% during lyophilisation of fish samples.

Bromine In

exceptionally

favourable

cases,

bromine

using the short-lived product nuclides m, r e s p e c t i v e l y ) .

However,

can

78Br

be analysed

or

most

sensitively

(half-lives 6.5 m and 17.6

particularly in multicomponent samples,

mostly the

gamma radiation of these nuclides is swamped by an intense, short-lived matrix background radiation. T h e r e f o r e , used.

This

veniently

reaction

is fairly

Rev.37).

krypton (Kato et a l . 9 1 9 ,

Br produced through

sensitive

measurable after about

Neider et al.®®",

77

too,

and

B r ( y , 2 n ) has to be

the product

1 d cooling period

A theoretically

7Q

nuclide is con-

(Aras et al.® 4 ®.

Rev.31,

possible f i r s t order interference by

R e v . 2 0 ) can be neglected.

Abe1·*·4® used "®Br and 80mg r f o r b r o l m n e analysis in halide mixtures.

Isomeric

583

state

photoexcitation

yielding

Engelmann and J e r o m e

122

79m

Br

has also been

, Breban et a l .

921

,

used

(Dams924,

Rev.29,

R e v . 1 0 2 ) . Veres and P a v l i c s e k 1 8 8

used a ®"co source for excitation. However, experimental difficulties arise due to the extremely s h o r t half-life of the measured nuclide (4.9 s ) . The formation of

79m

et a l .

B r by irradiation with gamma radiation from 195

was r e p o r t e d by Akbarov

. This method was also used for selenium activation (see t h e r e ) .

Many bromine compounds are volatilised u n d e r heat and radiation attack; should

therefore

carefully

check

for possible

losses

during

one

bremsstrahlung

exposure. Rubidium Among the photonuclide reactions usable for rubidium analysis

R b ( y , n ) 8 4 R b is

most f r e q u e n t l y used for its sensitivity and convenience r e g a r d i n g both halflife (34.5 d) and gamma e n e r g y (881 k e V ) . less favourable (Ülmez et a l . R e v . 3 3 )

86

R b can also be used but is much

due to poor s e n s i t i v i t y . First o r d e r

i n t e r f e r e n c e from strontium was found negligible at comparable concentration of both t a r g e t elements (ülmez et a l . , see above, Kato et al. 9 ·'· 9 , Rev.20) Hislop and Williams10"*7, Rev.65, found that at b r e m s s t r a h l u n g e n e r g i e s up to 40 MeV i n t e r f e r e n c e due to strontium and

89

Υ ( γ , α η ) a r e negligible if the c o r r e s p o n d i n g

t a r g e t elements lie before in comparable concentrations. Chattopadhyay"*"'® and Hui-Tu Tsai et a l . 1 1 4 6 s u g g e s t t h e selection of 20 MeV b r e m s s t r a h l u n g for a c t ivation.

T h e r e b y all competing reactions are ruled out although the threshold 86

e n e r g y of

S r ( Y , n p ) is somewhat lower (17.8 MeV). Galatanu and G r e s e s c u '

Rev.84, and D a m s 9 2 4 , Rev.29, reported the use of m, and Dams (see above) also reported

8

84m

,

R b with a half-life of 21

® m Rb (half-life = 1.02 m) a s usable f o r

analysis evaluation. Hui-Tu T s a i 1 1 4 7 used both

84

R b and

8

®Rb for evaluation of

rubidium analysis. Stronti um The reaction mostly used for strontium analysis, namely one of the

highest

specific product

88

Sr(Y,n)87mSr,

yields

activities encountered in all analytically

usable photon reactions. A d i s a d v a n t a g e is the relatively s h o r t half-life (2.81 h) of

87m

Sr.

However,

in the l i t e r a t u r e reviewed by the a u t h o r s ,

essentially

d i f f e r e n t f i n d i n g s were r e p o r t e d . Most of t h e workers did not detect any i n t e r f e r e n c e of

87m

S r or found it negligible if the concerned elements were p r e s e n t

in comparable amounts (Sato et a l . 1 0 5 2 , Rev.86, Kato et a l . 1 0 5 8 , Rev91, Hislop and Williams 1 0 2 7 , Rev.65, Kato et a l . 9 1 9 , R e v . 2 0 ) . Galatanu and G r e c e s c u 2 5 7 ,

584 R e v . 8 4 , mentioned s e v e r a l gamma-ray line o v e r l a p s , most of them usually i r r e levant.

One of them, namely t h e s p e c t r a l i n t e r f e r e n c e due to 388 keV from

produced t h r o u g h ly

this

127

Ι ( γ , η ) might gain importance in c e r t a i n m a t r i c e s , but most-

interference

can

be

ruled

Williams1027,

Rev.65,

neighbouring

372 keV line from

reported

both lines were found

out

by

distortion 43

K

short of

cooling

the

produced

by Das et a l . 5 1 > 1 0 5 3 ,

lation s p e c t r o m e t r y was

388

periods.

Hislop

and

peak

the

huge

keV

by calcium. Rev.87,

by

Complete o v e r l a p of

but in this c a s e

found

scintil-

used.

H o w e v e r , o t h e r a u t h o r s recommended t h e use of t h e 232 keV line from they

*26I

significant interference

by competing r e a c t i o n s

S r since

85m

due to yttrium and

z i r c o n i u m , o r gamma-ray line overlap (Galatanu and E n g e l m a n n 1 0 ® 8 ' 1 0 7 3 , 1 0 4 , 1 1 0 , r e s p e c t i v e l y , C h a t t o p a d h y a y and J e r v i s 8 8 3 ,

Rev.40).

Rev's.

Chattopadhyay330

recommended 20 MeV as b r e m s s t r a h l u n g e n e r g y to e x c l u d e f i r s t o r d e r i n t e r f e r e n c e by

90

ΖΓ(γ,αη).

trace

Isomeric

determinations

state

are

due to small c r o s s section The

photoexcitation

hardly

possible

used

by many w o r k e r s

of low

intrinsic

but

sensitivity

values.

( γ , ρ ) r e a c t i o n of strontium yielding

t o r i n g by H u i - T u T s a i et

was

because

al.

1146

83

R b was used for i n t e r n a l flux moni-

.

In l a r g e c o n c e n t r a t i o n s strontium can p r o d u c e a complex b a c k g r o u n d but normally with moderate s p e c i f i c a c t i v i t i e s . Yttrium oo using ° ° Y .

Yttrium can be well a n a l y s e d

I t s most prominent gamma-ray

energy

(1836 k e V ) usually o f f e r s an e x c e l l e n t p e a k - t o - b a c k g r o u n d r a t i o . At b r e m s s t r a h lung

energies

interferes cooling

by

90

normally

used

ΖΓ(γ,ηρ)

or

periods

modes of its

this

for

90

ΖΓ(γ,2η,β ). +

i n t e rg foe r e n c e

production,

photon can

Υ decays

activation

analysis,

only

zirconium

P a r t i c u l a r l y a f t e r l o n g , say

cause

difficulties

along a complex

since,

weeks,

due

function and

to

corrective

c a l c u l a t i o n s become complicated. However, due to t h e v e r y small a p p a r e n t section 88

Y

of t h e i n t e r f e r i n g

yield

average 91).

small at

natural

and

after

30

by

88

Y

93

MeV

LaFleur*148

counting of

reactions

Zr/Y

distribution

Interference

tectable Lutz

is

the

ratios

(Ölmez et a l . 9 5 3 ,

Nb(y,an)

is t h e o r e t i c a l l y

bremsstrahlung achieved

with two

contribution

concentration

optimal

Nal-crystals.

of zirconium

which

are

Rev.33,

sensitivity

(Kato (about

cross

to the

comparable

Kato et a l . 1 0 5 8 ,

possible,

irradiations

both

to

total the Rev.

but normally not d e et

al.919,

lpg)

by

Rev.20). coincidence

585 Photon

activation

analysis of yttrium

by isomeric state excitation

has

been

used f r e q u e n t l y (Lukens et al. 121,124^ R e v ' s . 23,24, respectively, Engelmann and Jerome* 2 2 and many o t h e r s ) with fairly good s e n s i t i v i t y . ®®mY was formed by r a dionuclide gamma excitation by Akbarov et al.

using gamma radiation from

F u r t h e r information about this application can be found in the s u b p a r a g r a p h on selenium. Yttrium emits a quite simple gamma-ray spectrum a f t e r activation with 30 MeV b r e m s s t r a h l u n g . T h e r e f o r e it has been used as an additive i n t e r n a l photon flux monitor (Segebade et al. 6 ®,

Rev.54).

Zirconium Zirconium has v e r y favourable p r o p e r t i e s for instrumental photon activation a n alysis

determination

regarding

effective activation

cross

section,

gamma-ray

data and half-life of the major product nuclide (® 9 Zr, half-life = 78 h ) .

Zir-

conium u n d e r g o e s many photonuclear reactions, but only t h r e e of them have been used for analysis,

namely those yielding " 9 Z r , 89m Z r

an(j

9 5 z r . -phe l a t t e r is

less sensitive and normally cannot be used if zirconium is p r e s e n t as a t r a c e component but the nuclide has the a d v a n t a g e of a longer half-life (64 d ) . is also produced through

9

"*Zr

photofission if appreciable amounts of fissile mater-

ial a r e p r e s e n t in the sample. However, in almost all cases 909 keV of ®9Zr has been used f o r analysis a s y e t . Tong et a l . H 4 9 recommended to u s e 20 MeV b r e m s s t r a h l u n g e n e r g y for activation to exclude all possible i n t e r f e r e n c e s from a d jacent elements. Aras et a l . 9 4 9 ,

Rev.31, found ®9Zr f r e e from i n t e r f e r e n c e by

niobium and molybdenum at 35 MeV b r e m s s t r a h l u n g e n e r g y . Chattopadhyay et a l . , oon ooo Ref s. * , Rev.40, found negligible contribution of niobium and molybdenum at 22 MeV activating b r e m s s t r a h l u n g e n e r g y and an overlapping gamma-ray peak from

204m

P b (911 keV) which could be discarded by allowing the nuclide to decay

out (half-life = 66.9 m). Kato et first

al.

919 1058

·

o r d e r i n t e r f e r e n c e by molybdenum

,

R e v ' s . 9 1 , 9 5 , respectively, found

detectable but

negligible at 30 MeV

b r e m s s t r a h l u n g activation. Hislop and Williams·'· 027 , Rev.65, i r r a d i a t i n g with 30 MeV b r e m s s t r a h l u n g , found no detectable contribution from molybdenum but minor i n t e r f e r e n c e from niobium. Several workers used short-lived

(half-life = 4.16 m) 89m Z r f o p

anaiysjs

eval-

uation (Galatanu and G r e c e s c u 2 5 7 , Rev.84, D a m s 9 2 4 , Rev.29, Oka et a l . 1 1 5 0 ) . In this case, the i n t e r f e r e n c e problems and their handling a r e virtually the same oq a s if Zr was u s e d .

586

If

zirconium

minerals)

is

one

present

has

in

to take

large

concentrations

into account

an

(e.g.

in

zircaloy

or

intense and l o n g - l i v e d

certain

background

activity.

Niobium

Niobium can be a n a l y s e d v e r y s e n s i t i v e l y half-life

is c o n v e n i e n t

It is the only ton

analytically

activation.

(James*!''*) isotope

(10.15

In

an

for

using the 934 keV line of

relatively

usable gamma-ray

early

^ut j j a s

d)

work

another

interference-free

line

92m

f o r niobium a n a l y s i s qo

isomeric

state of

Nb.

Nb

by

was

many o t h e r s ) .

T h e only r e l e v a n t

pho-

reported

been v e r i f i e d using photonuclear reaction of the

(Silva et a l . * * 2 and

The

measurement.

possible

stable

interfer-

e n c e is caused by gamma-ray peak o v e r l a p of 934 keV emitted by ®2Mn due to iron in

the

sample.

This

interference,

because

of

poor

f r e q u e n t l y can be n e g l e c t e d or easily be accounted Galatanu and E n g e l m a n n 1 " 6 8 , steel

matrix

is it

iating at l o w e r

necessary

(about

Rev.104). to discard

18 M e V )

specific

activity

f o r ( K a t o et a l . 9 1 9 ,

yield, Rev.20,

Only in the case of niobium a n a l y s e s in the i n t e r f e r i n g

bremsstrahlung

energy.

iron

reaction

First o r d e r

by

by molybdenum could not be d e t e c t e d d u r i n g a n a l y s i s work in the a u t h o r s ' ratory

but

was

found

by

Kato et al.*·"®®,

Rev.91,

under

similar

irrad-

interference labo-

experimental

conditions. Galatanu

et

al. 2 5 7 ' 2 5 8 ,

bremsstrahlung

of

a

Rev's.84,101,

betatron,

respectively,

obviously

did

irradiating

not detect

any

with

25

significant

MeV inter-

ference.

A b e * 1 9 5 analysed

niobium and tantalum s y n c h r o n e o u s l y

using an

NaI(Tl)-detector.

Molybdenum

140 keV

from

99m

Tc

is mostly used f o r molybdenum a n a l y s i s .

f a i r l y g o o d . H o w e v e r , since period

of

30

h

and the a p p a r e n t

is

99m

required,

The sensitivity

is

T c is a s e c o n d a r y decay p r o d u c t , a mimimum decay until

h a l f - l i f e is d e f i n e d

the

radioactive

(Ratynski

equilibrium

et a l . 1 " ® ^ ,

is

established

Rev.97).

Moreover,

the gamma-ray peak is located in an u n f a v o u r a b l e region of a normal gamma s p e c trum.

Therefore

activity

it is of a d v a n t a g e

measurements.

to use low e n e r g y

i n t e r f e r e n c e is possible only by ruthenium or rhodium, found n e g l i g i b l e ( C h a t t o p a d h y a y et a l . R e v . 4 0 , Ref's.1068'1073,

photon

spectrometry

for

Using b r e m s s t r a h l u n g e n e r g i e s up to 40 M e V , f i r s t o r d e r

Rev's.104,110,

respectively).

but these w e r e

normally

Galatanu and Engelmann,

T h e most intense possible

inter-

587

fering reaction of ruthenium, namely ρ ) , was only mentioned by Chattoooo padhyay and J e r v i s , Rev.40; this i n t e r f e r e n c e can be discarded by long (about 4-5 d) cooling period; a f t e r this time, of

99

by

Mo. Using photofission

99

Mo/

99m

of

fissile

9

9 m T c is only due to b e t a - d e c a y

T c for analysis one has f i r s t to check for i n t e r f e r e n c e material

short-time (minutes) irradiation

91m

possibly

present

in

the

sample.

Using

Mo (half-life = 65 s) h a s been used f o r a n -

alysis (Oka et a l . 9 0 7 , Rev.26, D a m s 9 2 4 , R e v . 2 9 ) . Tong et a l . 1 1 4 9 used molybdenum as an i n t e r n a l s t a n d a r d

in the analysis of zirconium

in Zr/Mo mixtures.

A f t e r irradiation with 20 MeV b r e m s s t r a h l u n g , ®®Zr was used f o r flux monitori n g . It was found that at this e n e r g y no appreciable activity of " 9 Z r (used for zirconium analysis) was produced by molybdenum. Ruthenium According to the l i t e r a t u r e accessible to the a u t h o r s ,

ruthenium was analysed

but twice by photon activation as yet (Weise and Segebade*® 5 , Rev.109, Oka et al. H " ' 2 ) . Both 9®Ru and

97

R u measured by gamma s p e c t r o m e t r y , and 9®Tc measured

by low e n e r g y photon spectrometry o r gamma spectrometry were used for analysis evaluation.

The achievable sensitivity is fairly good,

but

surely insufficient

in the most cases, r e g a r d i n g the extremely small n a t u r a l a b u n d a n c e of t h e element . I n t e r f e r e n c e by photofission p r o d u c t s have to be considered if

is used

f o r analysis. Rhodium The

analysis of rhodium

in trace

quantities entails difficulties in many

in-

strumental methods including photon activation. The photoreaction product best suitable

for analytical

Segebade^^,

purpose

is

191m

Rh

(half-life:

4.4

d;

see Weise and

Rev.109). However, this reaction is of relatively poor sensitivity

and the major gamma-ray energies a r e located in u n f a v o u r a b l e regions.

There-

fore, trace analyses mostly a r e not possible u n d e r reasonable experimental c o n ditions ( R a t y n s k i et a l . 1 0 ® 4 , R e v . 9 7 ) . Moreover, t h e product nuclide is s t r o n g ly i n t e r f e r e d by

102

Ρ ΰ ( γ , ρ ) . Breban et a l . 1 0 6 5 , Rev.99, used the ( γ , η ) p r o d u c t s

f o r analysis of rhodium in Black Concentrates;

they claimed a detection limit

of 1.5 micrograms. l " 2 R h was used as an internal flux monitor in t h e analysis of ruthenium in r h o dium as r e p o r t e d by Oka et al. l ^ 2 . They also performed rhodium analyses using

588 102

R h a f t e r activation with 20 MeV b r e m s s t r a h l u n g 1 1 5 3 .

Isomeric state photoexeitation was also proposed for rhodium analysis (Otvos et a l . 2 1 1 , Boivin et a l . B r e b a n only low e n e r g y , by

photons,

et al.® 2 1 , R e v . 102 and many o t h e r s ) . However,

primarily the c h a r a c t e r i s t i c Rh X - r a y s , a r e emitted

so t h a t low e n e r g y photon spectrometry can be used only; moreover,

t h e activity yield is relatively poor, and trace analyses a r e barely possible. Palladium Palladium can be analysed v e r y sensitively by the 296 keV-line of ^"^Pd using gamma s p e c t r o m e t r y , and yet more sensitively b y measuring 88 keV of low e n e r g y photon spectrometry (Weise and S e g e b a d e 1 5 5 , R e v . 1 0 9 ) . used

for

analysis

(Segebade

al.1071'

et

o f f e r s somewhat less sensitivity,

1072

,

Rev. 109).

using P d was also

latter

nuclide

but is more conveniently measurable because

Breban et a l . 1 0 6 5 ,

of its longer half-life (17 d ) .

The

103

Rev.99,

found 1289 keV of

most f a v o u r a b l e because of its freedom from any i n t e r f e r e n c e . Normally, activating with b r e m s s t r a h l u n g up to 40 MeV, all t h e mentioned r e a c tions

are

overlap.

relatively

free

from

Difficulties usually

first

arise

order

interference

predominantly

and

gamma-ray

from peak-to-Compton

line ratio

deterioration due to eventual intense background as was found in the a u t h o r s ' laboratory. If palladium

lies before in higher amounts

(e.g.

in Noble Metals

processing

c o n c e n t r a t e s ) it might i n t e r f e r e with the determination of many elements by an i n t e n s e and v e r y complex background gamma spectrum; the application of low e n e r g y photon s p e c t r o m e t r y is recommendable in this case. Silver Silver has been analysed with good sensitivity u s i n g 106m A g

and

105 A g >

T h e

for_

mer o f f e r s b e t t e r p e a k - t o - b a c k g r o u n d ratio if the higher gamma energies of t h e nuclide ( e . g .

1527 keV) a r e u s e d .

The l a t t e r ,

using the 344 keV-line has a

h i g h e r count rate yield. The short-lived isotopes ( 1 0 6 A g and

lu

° A g ) have been

used in exceptional cases only; the a r e produced with g r e a t activity yields but emit u n f a v o u r a b l e gamma-ray s p e c t r a . The analytical use of

108m

A g (half-life:

127 a) and h a s Snot r t e d in the l i t elow r a t uer ne e rinspected the a u t h o r s . measuring Weise e g e bbeen a d e 1 5r5e, p oRev.109, used g y photonbyspectrometry

589

the kX-emission of palladium d u r i n g analysis of silver in metals and o r e s . A comparison of the analytical r e s u l t s of silver obtained by

106m

A g and

l^Ag

yielded excellent agreement (see also Segebade et al. 1071, 1072^ R e v . 1 0 9 ) . B r e ban et a l . 1 0 6 5 ,

Rev.99, used the 280 keV gamma-ray line of

for analysis

evaluation. This line is somewhat more sensitive than the 344 keV p e a k , but in the most cases is subject to s t r o n g overlap i n t e r f e r e n c e by the 279 keV-line of 9 m Pb produced by lead possibly p r e s e n t in the sample. However, this i n t e r f e r e n c e can be discarded by Iong decay periods ( h e l M i f e of 105

compared with 41.3 d of

A g ) . Chattopahyay et

a

Pb · 51 · 9 h»

l . 3 3 0 ' 8 8 3 , Rev.40,

reported

possible f i r s t o r d e r i n t e r f e r e n c e of 106 m Ag by l " 8 C d ( Y , n p ) . In t h e case of e x cessive amounts of cadmium p r e s e n t they recommended to minimise its c o n t r i bution to to t h e common product activity by activation at 20 MeV electron e n e r g y . Dams®'*4, Rev.29, r e p o r t e d analyses using both the s h o r t - l i v e d photoneutron p r o d u c t s of silver (l"®Ag, *" 8 Ag), and also

and l " 9 m A g produced by iso-

meric s t a t e photoexcitation. The l a t t e r method has been recommended and applied b y many workers. As early a s 1942 the mentioned 1 01 nuclear levels were detected using photoexcitation (Feldmeier and Collins ); the two isomeres could be identified separately by Wolicki et al. ^ ^ in 1951. Most workers used accelerator b r e m s s t r a h l u n g

f o r excitation,

but also isotope sources,

®"Co in

partic-

ular were applied for photon activation analysis of silver (Law and Iddingsl®®, Veres and P a w l i c z e k 1 8 8 ) . Gamma radiation from ion (Akbarov et a l . s e e Apparently,

the

first

was also applied for e x c i t a t -

also selenium).

analytical

applications

of

photoexcitation

analysis

silver were made in the beginning of the 1960 s (Lukens et al. Otvos et a l . 2 1 1 ,

,

of

Rev.23,

Bilefeld1154).

Silver, if p r e s e n t in large concentrations, produces a v e r y i n t e n s e and complex b a c k g r o u n d a f t e r high e n e r g y photon activation. This is also t r u e in all o t h e r activation t e c h n i q u e s .

T h e r e f o r e , trace activation analyses in matrices bearing

silver as a major component are mostly not possible without chemical s e p a r ation. In some cases it is possible to circumvent i n t e r f e r e n c e t h r o u g h complex matrix spectrum by using low e n e r g y photon measurement; t h e s e s p e c t r a usually a r e much less complex than gamma-ray s p e c t r a (Weise and Segebade*·'·',

Rev.109).

Cadmium Among t h e numerous photonuclear reactions which cadmium u n d e r g o e s d u r i n g i r r a d iation

with

high

energy

bremsstrahlung

only

two a r e analytically

usable if

t r a c e cadmium determinations are r e q u i r e d , namely H 2 C d ( Y , n ) m m C d and

590 (γ,η,β~)1^ιηΙη.

Mostly the latter is used although the other yields

specific activity. However, the use of ences and its relatively Ref.

949

,

1Um

greater

C d is hampered by several interfer-

short half-life (49 m; Baciu et a l . 2 8 2 ,

Aras et a l . ,

Rev.31).

Ricci 9 1 ®, Rev. 18, see also R e f . 9 7 4 ,

studied the analytically useful cadmium re-

actions with bremsstrahlung energies up to 140 MeV and found a sensitivity ratio (100 being the greatest) of 1.2:2:0.6.

J e r v i s et a l .

Rev.40, C h a t t o p a d h y a y

1041

'

,

330 990

lllm

Cd:

105

Cd: 115Cd:

115m

In:

112

A g = 100:8.2:

Rev.74 (see also Chattopadhyay and J e r v i s 8 8 3 , ) , studied all detectable photonuclear cadmium re-

actions after irradiation with bremsstrahlung from 8 to 40 MeV in small increments. They s u g g e s t the use of

lllm

C d after 15 MeV bremsstrahlung activation.

They also report significant interference of

11!

>mi η produced by indium and tin.

During experimental work, these interferences were not found significant by the authors of this book, and if they eventually occur, their contribution to the common product nuclide can be easily discarded by allowing it to decay to negligible activity (see above, paragraph Sulin251,

6.2.3.4).

Galatanu and E n g e l m a n n 1 0 6 8 '

Berthelot and C a r r a r o

999

used both

115

1073

,

R e v ' s . 104,110, respectively,

C d and

115m

and

I n . The latter authors report-

ed excellent agreement between the results obtained by both reactions. However, the 527 keV line of ^ ^ C d might be overlapped by several other emissions ( e . g . 528 keV from

147

N d produced by neodymium) and the error thereby induced might

become significant if cadmium is present in trace concentrations. The isomeric state photoexcitation of

Cd

lllm

using either accelerator

brems-

strahlung or radioisotope gamma radiation was proposed by many authors, but the achievable sensitivity is limited so that trace analyses are mostly not possible. Indium Assuming that indium mostly is present in small trace quantities in samples to be analysed, its determination by photon activation is accompanied by several severe difficulties.

On the one hand,

many photon reactions of indium

yield

large product activities. On the other hand, the product nuclides either have unconveniently short half-lives ( 1 1 2 I n ,

112m

In,

u l m

In,

I n ) and/or emit gam-

ma-rays with unfavourable energies ( 1 1 2 m I n ,

113m

are emitted with poor abundances ( 1 1 2 I n ,

I n ) . The nuclide produced during

114

In,

114

114m

I n ) or the gamma-rays

high energy accelerator irradiation which is most suitable for analysis

591 is produced by reaction with photoneutrons and thus of limited usability.

Moreover,

all reactions are possibly subject

to

first

order

interference

by tin and cadmium. Kuttemperoor and K u b i s k e 2 4 4

studied the photonuclear reactions of indium at

bremsstrahlung energies up to 25 MeV generated by a betatron. Oka and K a t o 1 1 4 2 used

as an internal monitor in the analysis of

mixtures. with

However,

fairly

good

a relatively

sensitivity

interference-free

gallium/indium/thallium

photon

activation

is only achievable by irradiating

analysis

at low

brems-

strahlung energies to exclude competing reactions (Chattopadhyay et a i . 330,883^ R e v . 4 0 ) exploiting the isomeric state photoexcitation.

was first produc1 09 ed by photoexcitation as early as 1939 (Waldman et al. ) . The first analytical application plication

of

was reported by Harbottle^®^. isomeric

state

photoexcitation

used this method with surprisingly claimed a detection

(Besides,

to analysis

good sensitivity;

this was the at a l l ) .

first

Many

Veres and

ap-

authors 1 DO

Pavliczek

limit of 20 Vig/g of indium in a 50 g metal alloy

sample

using a ®®Co gamma-ray source for photoexcitation. The same detection limit was achieved by Breban et a l . ® 2 * , R e v . 1 0 2 , using 6-8 MeV bremsstrahlung of a linear accelerator. However, in the "normal" analytical case, i . e . traces (micrograms per gram and less) determinations in small, say tens of milligrams, instrumental

photon activation

analysis

will surely

sample masses

required,

not be the method of the

choice. Tin T h e most sensitive reaction of tin is iently long half-life

has a conven-

(14 d) but emits only one single gamma-ray line,

namely

the isomeric conversion energy of 158 keV. In gamma-ray spectra, this is located very unfavourably; this energy region,

many photonuclear reaction products emit gamma-rays in

and mostly the 159 keV line of

and/or calcium dominates. Therefore, metry. high,

Its major gamma emission energy is

relatively

free

from

produced by titanium

is best used in gamma-ray spectro(245 k e V ) ,

interference

satisfactory in the most cases, although

and

although not appreciably

the

achievable

sensitivity

is

excels. However, the latter can

well be exploited using low energy photon spectrometry. Modern planar low e n e r gy photon diodes have sufficient resolution capability to enable a spectral s e paration of the gamma energies from

and

(159.4 keV and 158.4 keV,

r e s p e c t i v e l y ) . Moreover, the low gamma-ray energy of

η (E=171 keV) can be

592 measured

simultaneously

gamma-ray line of

117m

for verification

of

the

results.

This line,

as

also

S n , cannot be resolved rigorously from eventually o c c u r -

r i n g n e i g h b o u r i n g gamma-ray energies in normal gamma-ray spectrometry ( e . g . 166 keV from

139

Ce,

At irradiation

175 keV from

48

Sc e t c . ) .

e n e r g i e s up to about 40 MeV, significant

ence has not been o b s e r v e d , and ^ I n

first

order

interfer-

can only be i n t e r f e r e d by appreciable

concentrations of indium in t h e sample. C h a t t o p a d h y a y 3 3 0 used

117m

S n measuring

with a coaxial Ge(Li)-detector a f t e r long (more than 3 weeks) decay 47

periods.

S c had then decayed to quasi-zero activity and all o t h e r possible sources of

i n t e r f e r e n c e were assumed negligible. Galatanu et a l . 2 5 7 , Rev.84, used 160 keV emitted by

123m

S n . They mentioned many sources of i n t e r f e r e n c e , particularly in

the case of rock and ore matrix analysed,

but t h e r e was no information given

about the management of t h e i n t e r f e r e n c e s . However, this problem was discussed in detail in a later publication of the same authors 2 ®". The same reaction was also used by Nguyen et a l . 1 2 0 1 · Very high activity yield of

117

1202

.

I n was obtained a f t e r activation with 110 MeV

b r e m s s t r a h l u n g as r e p o r t e d by R i c c i 9 ^ , Rev.18. However, multiple i n t e r f e r e n c e by competing reactions and gamma-ray overlap has to be taken into account in this case, particularly d u r i n g analysis of multicomponent samples. Several w o r k e r s also proposed the

analytical

al. 9 2 1 ,

isomeric state photoexcitation

with

accelerator

but the activity yield of ^ 7 m S n is extremely small and hence

bremsstrahlung,

sensitivity

is mostly insufficient

(Otvos et a l . B r e b a n

et

Rev.102).

If tin is p r e s e n t background

in l a r g e r amounts it emits an intense,

a f t e r high e n e r g y photon exposure,

complex

gamma-ray

and t h u s trace quantities of

o t h e r components might not be detectable. Antimony

Antimony can be analysed quasi-selectively with excellent sensitivity by

1 99 ^"Sb

produced t h r o u g h l 2 3 S b ( y , n ) . Half-life and major gamma e n e r g y a r e f a v o u r a b l e . Theoretically possible i n t e r f e r e n c e by competing reactions of tellurium

normal-

ly a r e unlikely to occur because of the low natural abundance ofι ο the element τ and the small concentration of the possibly i n t e r f e r i n g isotope in the n a t u r a l mixture (0.87%).

593 Hislop and W i l l i a m s * R e v . 6 5 ,

reported i n t e r f e r e n c e from tellurium,

but in

this special case antimony and tellurium were p r e s e n t in equal amounts. Aras et al.Rev.31,

however, reported no detectable i n t e r f e r e n c e u n d e r comparable

conditions. Hislop and Williams (see above) and Carter et al. 1 "91 > Rev. 120, al12( m

so used

^ Sb for confirmation of the obtained

sensitivity

but

values.

120m

Sb

o f f e r s less

has a longer half-life. No i n t e r f e r e n c e was reported for this

C h a t t o p a d h y a y 3 3 " irradiated at 15 MeV to discard i n t e r f e r e n c e from

nuclide. tellurium.

T h e use of

120

S b (half-life = 15.9 m) was mentioned only once in the l i t e r a t u r e

accessible to the a u t h o r s (Dams 9 2 ^,

Rev.29).

Antimony, if p r e s e n t at h i g h e r concentrations, may cause i n t e r f e r e n c e by c r e a t ing an intense b a c k g r o u n d activity; the gamma-ray spectrum is not too complex, but p e a k - t o - b a c k g r o u n d ratios might be d e g r a d e d by activities due to antimony in the matrix. Tellurium T h e r e a r e v e r y few r e p o r t s about tellurium analyses using photon activation; among the l i t e r a t u r e inspected by the a u t h o r s , not more than t h r e e p a p e r s r e port tellurium analysis. in the a u t h o r s ' isotope.

^ 2 ^Te was found suitable for analysis d u r i n g

laboratory.

Campbell and Steele*""",

Rev.47,

studies

also used

It o f f e r s fairly good sensitivity and is f r e e from f i r s t o r d e r

this

inter-

f e r e n c e by neighbouring elements at b r e m s s t r a h l u n g energies up to 40 MeV. Campbell and Steele r e p o r t possible overlap i n t e r f e r e n c e of t h e major gamma-ray 69

line by

Ge (half-life = 39 h, E=574 k e V ) , but this can be ruled out by a min-

imum cooling period of t h r e e weeks. A special a d v a n t a g e of photon activation used for tellurium analysis as compared with neutron activation is its freedom from first o r d e r i n t e r f e r e n c e by fission p r o d u c t s from thorium and uranium p o s sibly p r e s e n t in the matrix. Chattopadhyay et a l . 3 3 0 , 8 8 3 ,

Rev.40, used

129

Te

and found that at an irradiation e n e r g y of 20 MeV it was not i n t e r f e r e d . However,

* 2 9 T e is a fairly a b u n d a n t

isotope,

fission

product,

and t h e r e f o r e ,

one has to check for l a r g e r concentrations of

fissile

using

this

material in the

sample prior to analysis. Iodine Iodine can be analysed conveniently with excellent sensitivity by instrumental photon activation analysis. *2®I has been used almost exclusively. This isotope

594

is f r e e from interference by competing reactions. However, the gamma-ray e n e r gies (388 and 666 k e V ) frequently are overlapped by gamma-ray lines from ® 7 m Sr (388 k e V ) and/or

132Cs

(668 k e V ) , respectively. The former interference mostly

can be avoided by longer cooling periods or, if produced by

89Υ(γ,2η),

87mSr

is a decay product of

87Y

by use of low bremsstrahlung energies (up to 20 M e V ) .

The overlap by 668 keV from ^ ^ C s cannot be circumvented. However, using modern,

ultra-high

resolution

germanium

detectors,

it should be possible to se-

parate both lines insofar as they can be unfolded mathematically

with help of

appropriate computer routines during spectra processing (Reimers and Fusban, Ref.694).

Another wayout is the application of low energy photon spectrometry

measuring the k X - r a y line of tellurium emitted by

126I

which is not i n t e r f e r e d .

Both spectroscopy methods yield comparable sensitivities.

Hui-Tu Tsai et al. 1 1 5 5 used mixtures

after

activation

126I,

with

124I

and

123I

bremsstrahlung

for analysis of caesium/iodine energies

up to 65 MeV.

produced by caesium, served as an internal photon flux monitor. Several authors (Kato et

al.919'956,

R e v ' s . 20,36,

respectively,

Galatanu and

Engelmann 1 0 6 8 ,

R e v . 104) report possible first order interference by xenon. However, in nearly all cases this source of e r r o r surely can be neglected. Aras et a l . 9 4 9 , recommended

a cooling

from ®^Br and

132Cs.

time of about

10 days to exclude overlap

Rev.31,

interference

It remains unclear why in this case the interference due

to caesium was negligible ( h a l f - l i f e of

132Cs

= 6.47 d ) .

A common problem in the different activation analysis techniques as applied to iodine

determinations

is

the

volatility

of

this element

and

many of

its

com-

pounds. Williams and H i s l o p 9 7 9 , Rev.77, undertook a thorough study about photon activation

analysis

of

iodine,

focussing

its

behaviour

under

bremsstrahlung

bombardment and heat attack. In particular they studied iodine as encountered in

soil

environment.

Significant

losses

of

but no detectable changes of concentration to h i g h - e n e r g y bremsstrahlung,

iodine

during

heating

were

during multiple long-time

particularly

tions against iation,

e. g .

in organic

matrix,

it

is recommendable

loss of volatile iodine prior to or during by

cooling

during

exposure

although most of the iodine content in soils is

probably bound organically and thus rather volatile ( W h i t e h e a d 1 1 5 6 ) . less,

stated

Nonethe-

to provide

precau-

bremsstrahlung

irrad-

activation or sealing of the sample in approp-

riate containments. Caesium

With help of

132Cs,

caesium can be analysed with excellent sensitivity.

Using

595 bremsstrahlung energies of up to 35 MeV, competing reactions are unlikely to i n t e r f e r e . However, the only usable gamma-ray line (E=668 keV) partly coincides with the 666 keV line from

as mentioned in the preceding

Since the other gamma energy of

126I

subparagraph.

might also be interfered (see above) it is

of limited use as a reference line for an eventual interference computing routine.

Therefore,

the only wayout in the case of significant overlap

interfer-

ence is to use low energy photon spectrometry measuring the very intense xenon kX-radiation effected by the electron capture decay of found

the

668 kev line of

132Cs.

Chattopadhyay 3 3 0

Cs free from interference if measured at least

three days a f t e r irradiation with 15 MeV bremsstrahlung. The above discussed interference

by

iodine

was not

mentioned

although

in the analysed

samples

(sewage sludges) iodine is not unlikely to be present in measurable amounts. Hui-Tu Tsai et a l . 1 1 5 5 used the (γ, 2pn)-reaction of caesium as an internal flux monitor in the analysis of iodine with up to 65 MeV bremsstrahlung (see a b o v e ) . The photoreactions of caesium at extremely high (250 MeV) bremsstrahlung e n e r gies were investigated by Kato and Hui-Tu T s a r * · 1 ^ . Barium The most sensitive photonuclear reaction of barium yielding a long-lived

(more

than

sensi-

1 d half-life) radionuclide

is ^ ^ Β β ί γ , η ) .

The reaction

is fairly

tive but the yielded spectrum is subject to overlap i n t e r f e r e n c e .

The reaction

product

unfavourable

emits one single gamma-ray line which is located in an

energy region

(E=2 68 k e V ) .

However, interference due to competing

reactions

were found negligible by most workers (see e . g . Kato et ai. 919» 1058 (

Rev's.91

and 95, respectively, Chattopadhyay et a i . 330,883^ R e v . 4 0 , and many o t h e r s ) . In the authors' laboratory, low energy photon spectrometry has been applied s u c cessfully, measuring the very intense barium kX emission by internal conversion of the

135mBa

level. Low energy gamma-ray lines have been used, too: 123 keV of 131Ba

and 66.9 keV from

measured

136Cs

interference-free,

produced through but

the

137Ββ(γ,ρ).

achievable

These lines can be

sensitivity

is

comparatively

poor. 137m ß a

hag

been

usecj

frequently (see e . g . D a m s 9 2 4 , R e v . 2 9 ) . Depending upon the

incident photon energy, this nuclide is produced either by photoneutron tion or by isomeric state photoexcitation. analytical sensitivity can be achieved.

In the former case,

extremely

reachigh

Chattopadhyay 3 3 ® found first order i n -

terference by lanthanum. However, during experimental work in the a u t h o r s ' laboratory the contribution of lanthanum to the ^ 3 7 m B a activity was found neg-

596 ligible. Using accelerator bremsstrahlung, several authors reported good sensitivity for analysis

through

isomeric

state

photoexcitation

(Lukens

et

al.Rev.23,

Engelmann and J e r o m e 1 2 2 , Breban et a l . 9 2 1 , R e v . 1 0 2 ) . L u k e n s 1 2 4 , Rev.24, used 15 MeV bremsstrahlung and thus probably yielded higher activity through photoneutron reaction than by photoexcitation.

produced by radionuclide gamma

isomeric state excitation was also applied but with very poor sensitivity (Law and I d d i n g s 1 ® 9 ) . However, in this case a

source was used for excitation

and thus higher activity yields could not be expected. 136

C s produced by

137

Β β ( γ , ρ ) was used a s an internal flux monitor in the analy-

s i s of caesium in B a / C s mixtures after activation with 18 MeV bremsstrahlung (Hui-Tu T s a i 1 1 5 7 ) . The lanthanide elements For most of the lanthanide elements, thermal neutron activation analysis is by far the most sensitive analysis technique, more sensitive than photon activation by many o r d e r s of magnitude in many c a s e s . Moreover, for some of the elements,

no

analytically

suitable

photonuclear

reaction

is

available

using

bremsstrahlung energies up to say 45 MeV. However, there are some drawbacks of neutron activation analysis as applied to the Rare E a r t h s . First, a high sensitivity does not guarantee a high quality level of the analytical results a s e x p r e s s e d in terms of their accuracy and precision; the extremely large neutron activation c r o s s sections might be a source of trouble a s well since they cover a large range from about one to several thousands of barns, and thereby, for instance in a multioomponent Rare Earth compound mixture, the inter-elemental distribution

of the induced activity is extremely

inhomogeneous.

larger amounts of Rare Earth elements are present in the sample, matrix attenuation

Second,

if

significant

of the neutron beam might lead to miscalculations in the

evaluation procedure.

Instead,

the function of the photonuclear cross section

with the atomic number of the target element is fairly smooth (see chapter 2) and thus differences in the induced activities are not extremely large.

More-

over, since the photoneutron cross sections of the Rare Earth elements generally are much lower than those for thermal neutrons,

there is no danger of

significant activating beam attenuation within the sample matrix. Extensive studies of the analytically usable photonuclear reactions of the Rare Earth elements were published by Oka et a l . 9 4 3 who used 20 MeV bremsstrahlung,

597

Owlya et al.

using bremsstrahlung energies from 25 through 45 MeV, Kato and

Voigt 3 "®, Rev.30, at an activating bremsstrahlung energy of 70 MeV and several others. However,

probably because of the above mentioned sensitivity limitations,

ton activation,

according to the literature inspected by the authors,

pho-

has been

applied to Rare Earth element analyses in few cases as y e t . Mostly these elements are present in small traces (except perhaps lanthanum, cerium and neodymium), and therefore thermal neutron activation excels. Several of the lanthanides,

if present in larger amounts,

ence in photon activation analysis

may cause i n t e r f e r -

(as also in neutron activation analysis)

by

producing a complex background gamma spectrum; frequently it is of advantage to use low energy photon spectrometry when analysing lanthanide elements; the k X lines can be well separated and interference by spectral line overlap either is not probable or can easily

be accounted for as experiments performed in the

authors' laboratory have shown. Lanthanum

Up to a bremsstrahlung

energy of 40 MeV, there is no photonuclear

reaction

suitable for trace lanthanum analysis.

As indicated in the tables in Ch.5,

highest activity

produced by

yield is due to

14 ^La

(η,γ)-reaction

the

with photo-

neutrons. As f a r as the authors know, no attempt has been made to analyse lanthanum by

photon activation.

The photonuclear reactions of lanthanum at e x -

tremely high (250 MeV) bremsstrahlung energies were investigated by Kato and Hui-Tu

Tsai1194.

Cerium and also by

where-

by the former enables greater sensitivity and more advantageous

Cerium can be analysed with good sensitivity by

peak-to-back-

ground ratio than the latter. In normal gamma spectrometry, the major gamma-ray lines of both activation products

(165 and 145 keV, r e s p e c t i v e l y ) s u f f e r from

the close vicinity of 159 keV emitted by several radionuclides which frequently are highly

abundant

in photon-activated samples ( e . g .

4^Sc).

T h e r e f o r e it is

recommendable to use low energy photon spectrometry. In a spectrum collected with a planar low energy photon diode both mentioned lines are clearly separated from other lines appearing in "normal" photon-activated

material.

Moreover,

the lanthanum k X - r a y lines emitted during electron capture decay of

can

598 be measured i n t e r f e r e n c e - f r e e .

Extremely high analytical s e n s i t i v i t y for cerium

was found by Oka et a l . 9 0 7 , R e v . 5 , u s i n g produced

t h r o u g h activation

139m

C e ( h a l f - l i f e = 56.5 s , E=754 keV)

with 20 MeV b r e m s s t r a h l u n g ;

a detection limit of

l e s s than 1 microgram was s t a t e d . Praseodymium As also in the c a s e of lanthanum, lear reaction

t h e r e is no analytically s u i t a b l e

for a n a l y s i s of praseodymium.

photonuc-

The h i g h e s t a c t i v i t y level induced

by a c c e l e r a t o r irradiation is due to an ( η , γ ) p r o d u c t of a reaction with photoneutrons

(142Pr).

Dams924,

activity is extremely

R e v . 2 9 , r e p o r t e d the u s e of

140

P r . The a c h i e v a b l e

high but the nuclide does not emit an analytically

usable

gamma e n e r g y . Dams r e p o r t e d the use of the u n s p e c i f i c 511 keV annihilation r a diation due to the positron emission of to overcome

140

the inavoidable i n t e r f e r e n c e

e m i t t e r s , among them

P r . However, it remains unclear how by

many other

short-lived

positron

being the most prominent.

Neodymium 147

N d produced through

148

N d ( r , n ) o f f e r s fairly good analytical s e n s i t i v i t y and

has a convenient half-life (10.98 d ) .

However, the 531 keV line is s u b j e c t to

i n t e r f e r e n c e by other closely n e i g h b o u r i n g gamma e n e r g i e s

(e.g.

528 keV from

p r o d u c e d by cadmium). T h e r e f o r e it is of a d v a n t a g e to use low e n e r g y photon s p e c t r o m e t r y

measuring the prometium k X - r a y e n e r g i e s a n d / o r the 91 keV

gamma-ray line, .both emitted by * 4 7 N d . The latter might be o v e r l a p p e d by 91 keV from

Cu p r o d u c e d

by zinc p o s s i b l y p r e s e n t in the sample. This

contribution fi7

can easily be accounted for u s i n g other gamma-ray lines emitted by ° Cu a s a reference, ratory

(e.g.

it was

93 k e V ) . During practical a n a l y s i s work in the a u t h o r s '

found that negligible

degradation

labo-

of the quality of the a n a l y t i -

cal r e s u l t s was e f f e c t e d t h r o u g h the correction routine in this c a s e . 141m N ( j ( h a i f _ i i f e = 62 s , E=757 keV) has also been used for neodymium a n a l y s e s a f t e r s h o r t - p e r i o d a c t i v a t i o n s (Oka et a l . 9 0 7 ,

Rev.5, Dams924,

Rev.29).

Samarium In f a v o u r a b l e c a s e s ,

i.e.

if the concentration

is not below s a y one

microgram

per gram and if t h e r e is no e x c e s s i v e matrix b a c k g r o u n d r a d i a t i o n , samarium can be a n a l y s e d by ^ S m

using low e n e r g y photon s p e c t r o m e t r y (E=103 keV and the

europium X - r a y s e r i e s ) . However, the analytical s e n s i t i v i t y is poor, and the

599 application samarium

of instrumental

photon activation

analysis to the determination

was reported in the literature accessible

(Berthelot

et a l . H " ' 8 ) .

Photon activation

for trace samarium analysis,

to the authors only

of

once

surely is not the method of choice

but thermal neutron activation is only superior in

terms of activity yields; since the same radionuclide is produced by both t e c h niques,

the mentioned restrictions also apply to neutron activation.

Samarium

has been used as an additive internal flux monitor in routine multielement analyses in the a u t h o r s ' laboratory (Segebade et al.®",

Rev.54).

Europium T h e photonuclear reaction product of europium which is most suitable for analysis is

152m2Eu.

150mEu

can also be used.

The half-lives of both are

rather

short ( 9 . 3 h and 12.8 h, respectively) which somewhat limits the detectability of the

element.

insufficient that

thermal

since

The intrinsic

sensitivity

is good but

normally europium appears in very

neutron

activation

analysis

rather

than

might

be

small concentrations

nevertheless

so

photon activation

normally be the method chosen. Except for several systematic studies,

would the au-

thors could find but two messages about photon activation analysis of europium (Korthoven et a l . 3 0 7 ,

R e v . 106, Berthelot et a l . 1 1 5 8 .

measured with a scintillation crystal,

The former used

152mlEu

the latter applied high resolution

spec-

trometry measuring both the 122 keV line and the samarium k X - r a y emission of the same nuclide and found good agreement o f the results obtained using both lines.

The application of instrumental photon activation analysis in both cases

was of particular advantage compared with neutron activation; Korthoven et al. analysed alloys containing

high lanthanide metal concentrations and

Berthelot

and co-workers analysed boron matrix, so that in the case of thermal neutron activation both would have to face serious problems in terms of matrix a b s o r p tion. Gadolinium T h e r e is only one photon activation product which is practically usable for gadolinium

analysis,

namely ^^Gd

(half-life = 18.56 h ) .

Since its most intense

gamma-ray line (E=364 keV) is closely adjacent to very strong gamma emissions of nuclides which frequently are produced in multicomponent photon activation ( e . g .

43K,

87mSr)

matrices

during

it is recommendable to use low energy pho-

ton spectrometry and select the k X - r a y s of terbium and/or the 58 keV gamma-ray line (Oka et a l . 9 2 4 ,

Korthoven et a l . 3 0 7 ,

Rev.106,

Berthelot et a l . 1 1 5 8 ) .

How-

e v e r , in the most eases the sensitivity of the method i s insufficient because

600

of the low natural abundance of gadolinium.

Terbium As

is also true

induced

to

for

several other Rare Earth elements,

terbium

photoneutrons;

during

accelerator

the ( y , n ) - p r o d u c t

irradiation

d),

but,

being a ( γ , 3 η )

due

to

activity

reaction

with

has a half-life of 150 years and therefore is

produced in extremely small quantities. (5.4

is

the greatest

has a more convenient

half-life

product, is also produced only in small activi-

ties. Inspecting the literature, the authors found only one paper dealing with photon activation

analysis of

terbium

(Oka et a l . R e v . 5 ) .

They

used the

short-

lived 158mrp^j ( h a l f - l i f e = 10.5 s ) produced by 20 MeV activation. However,

for

trace analyses of terbium one will normally not select photon activation. Dysprosium Dysprosium

can be analysed 155Dy

( h a l f - l i f e = 8.1 h ) . et a l . H o w e v e r , ly)

frequently

with

fairly

good

sensitivity

with

help of

(half-life = 9.59 h) has also been used

157Dy

(Berthelot

the gamma-ray energies (326 keV and 227 keV, r e s p e c t i v e -

are subject to overlap interference in a multi-component

spec-

trum, assuming trace quantities of dysprosium to be analysed. The use of low energy

photon

spectrometry is also troublesome because the resulting

terbium

k X - r a y lines are emitted by both mentioned product nuclides at comparable intensities. T h e r e b y , ever,

r e s p e c t i v e l y ) and, the

the common decay function of these lines is complex. How-

the half-lives of both nuclides are not too different ( 8 . 1 h and 9.59 h,

analysis

depending upon the requirements concerning the quality of

results,

the

induced

error

might

be negligible

when

fitting

an

average half-life into the common decay function.

Holmium Half-lives and photon energies of the ( y , n ) - p r o d u c t s of holmium are extremely inconvenient; there is no suitable reaction f o r trace holmium analysis. Dams®^, Rev.29, reported the analysis of holmium measuring the low energy photon emission of

164mHo

after activation with 35 MeV bremsstrahlung.

601

Erbium A s also in the case of holmium, there is no practically usable photonuclear r e action for analysis of erbium using

gamma-ray

spectrometry;

lives of the activation products are unsuitable ( 1 6 * E r , not emit a measurable gamma energy

either the halfand/or they do

However, using low energy

photon spectrometry one can exploit the v e r y intense holmium kX-emission due to the electron capture decay of

and also the thulium k X - r a y s due to

^Er.

Both nuclides can be produced with large specific activities during bremsstrahlung bombardment, but the latter might be interfered by l® 9 Yb produced through ytterbium activation.

As f a r as the authors know, there is no reference about

the analytical use of

photonuclear reactions for erbium analysis.

frequent analytical use was made of lower incident

photon energies.

Nonetheless,

167mEr produced by photoexcitation

Excellent selectivity and fairly good

with

sensitiv-

ity were found by many workers using accelerator bremsstrahlung ( D a m s 9 2 4 , R e v . 29, L u k e n s 1 2 4 ,

Rev.24, Ivanov et a l . 1 0 5 5 . , Rev.89, Breban et a l . 9 2 1 .

and many o t h e r s ) or isotope source gamma-rays

Rev.102,

(Veres*9^).

Thulium Both the ( γ , η ) and the ( γ , 2 η ) products can be applied f o r fairly sensitive thulium analyses.

Using the latter it is recommendable to select accelerator

elec-

tron energies not less than 30 MeV. However, the major gamma-ray lines of both nuclides are

subject

to severe overlap interference

many multi-component samples, e . g . from

120mSb

198 keV of

produced by antimony,

overlapped by 208 keV from

2

^ U or

by elements occurring

in

is interfered by 197 keV

or 208 keV of

1 6 7 Tm

is nearly

completely

here again, low energy photon spectro-

metry might prove superior since the erbium X-ray emission can only be i n t e r f e r e d by

produced through ^®^Ηο(η,γ) b y photoneutrons. T h i s interference

can be discarded by sufficiently long cooling periods (about 14 d ) or neutron shielding of the sample during irradiation, e . g . with cadmium foil.

Photon

activation

Hislop and

analysis

Williams 952 ,

of

thulium

was reported

by Oka et a l . 9 4 2

and

Rev.32. Both used the 198 keV gamma-ray line of

by

168Tm.

Ytterbium T h e most sensitive photonuclear reaction of ytterbium is ^ ® Y b ( Y , n ) ^ ® Y b . achievable sensitivity

is good and the product

nuclide has a convenient

The half-

life (4.2 d ) , but the gamma-ray energies with sufficient abundances are rather

602

low (up to 396 k e V ) . A few other activation products can also be used for analysis ( e . g .

173Tm,

169Yb)

but enable considerably less sensitivity.

The authors found but one reference about ytterbium analysis by photon activation

(Dams 9 2 4 ,

However,

Rev.29).

in the

insufficient

for

17.7 s - 1 6 7 Y b

was used after short-period

most cases the analytical ytterbium

sensitivity

activation.

of photon activation

analysis due to the poor natural abundance of

is the

element. Surprisingly, no attempt has been made, as f a r as the authors know, to use isomeric state photoexcitation measuring ^ 7 ® m Yb.

Lutetium The analytically

most suitable photonuclear

process yielding

172Lu.

whose and

half-lives are too long

1.37 a,

reaction of lutetium is the

(γ,3η)

Both the ( γ , η ) and the ( γ , 2 η ) reaction yield isotopes

respectively)

to produce

sufficient specific activities

f o r trace analysis.

l74mLu

(3.31 a

(half-life = 142 d )

does

not emit a suitable photon spectrum. The authors could not find any publication in

which

the application

of

photonuclear

reaction

to anlyses of

lutetium

was

mentioned.

Analysis of the element using isomeric state photoexcitation is possible et

a l . L u k e n s

et al.

Rev.23),

but v e r y

poor sensitivities

(Otvos

have

been

stated.

Law and Iddings^·® 9 attempted to use a ®"co gamma-ray source f o r excitation but could

not

detect

any

activity

after irradiation

except

the natural

radiolute-

tium radiation. Hafnium Hf(y,n ) 1 7 5 H f been

applied

in

is the most sensitive photonuclear reaction of hafnium. It has the authors'

laboratory

for analysis of hafnium in

oxide matrix ( u n p u b l i s h e d ) . The major gamma e n e r g y of

1 7 5 Hf

zirconium

(344 k e V ) might be

interfered by ^'"'Ag (E=344 k e V ) produced by silver and/or cadmium possibly p r e sent

in the sample.

As far as it is known to the authors,

no application

of

this reaction f o r hafnium analyses was published.

Instead, isomeric state photoexcitation frequently has been used by many workers,

mostly measuring

179mHf

nable with this technique,

( h a l f - l i f e = 18.7 s ) . Among all elements determi-

hafnium apparently has the most advantageous

proper-

603 ties and can be analysed with good sensitivity using accelerator bremsstrahlung (Kodiri et a l . 1 1 5 9 , Otvos et a l . 2 1 1 , Lukens et a l 1 2 1 , Rev.23, Breban et a l . 9 2 1 , Rev.102, Ivanov et al. 1 0 5 5 , Rev.89, and many o t h e r s ) . Law and I d d i n g s 1 8 9 did not detect appreciable activity after irradiation of hafnium with gamma-rays of a ®"Co source. Akbarov et al.

used gamma-rays from

for in-situ excitat-

ion of hafnium and yielded fairly good sensitivity. See also selenium. Tantalum Among the photonuclear reaction products of tantalum, 180mrpa

can

procjuceci

with the highest activity yield. However, its gamma-ray energies are low (93 and 104 keV) and have small abundances (4 and 1 emissions per one hundred disintegrations,

respectively). Therefore, it is of advantage to measure the haf-

nium kX-ray emission due to the electron capture decay of 180m T a

js

muc

h

more intense than its gamma radiation (Berthelot et a l . I " " · * , R e v . 5 2 ) . See also Abe1195. 180mj|f produced through ^ T a ( y , p ) can also be applied. On the one hand, the activity yield is much lower than that of the above named reaction, but on the other hand, 180mH£

em

jts

a

gamma-ray spectrum which is much more conveniently

measurable. Using the 93 keV gamma-ray line of ! 8 0 m T a f Q r tantalum analyses in geological material, Galatanu et a l . 2 5 7 , 2 5 ® ,

Rev.84 and 101, respectively, found spectral

interference by many elements. Ricci 9 *'', Rev. 18, used ISOm^jf after activation with 105 MeV bremsstrahlung.

However, in instrumental multielement analyses,

activation with this energy entails a lot of interference problems.

Neverthe-

less, excellent sensitivity was found. Tungsten During bremsstrahlung irradiation of tungsten, among the numerous photonuclear reactions the highest activity is yielded by * 8 2 \ν(γ,η) 1 ®*νν. However, the gammaray lines of

have insufficient emission probabilities,

therefore low ener-

gy photon spectrometry measuring the tantalum kX-ray lines is superior to gamma spectroscopy (Berthelot et a l . 1 0 0 5 ,

R e v . 5 2 ) . The achievable sensitivity is e x -

cellent. In gamma spectra of photon-activated tungsten taken after decay periods of not more than say a week, the most prominent lines are emitted by produced by photoneutrons.

604

183Ta

produced through * 8 4 ν ν ( γ , ρ ) is also well measurable, but much less sensi-

tive than the above quoted reaction yielding ^ V V . 183mw produced through isomeric state photoexcitation

was used for tungsten analysis by many

workers.

However, the achievable sensitivity is rather poor; therefore, if trace determinations are required, this technique cannot be applied.

Tungsten,

if present as a major component, may be a source of spectral i n t e r 1ft7

ference through

lolW.

However, the associated neutron reaction can be avoided

b y neutron shielding, either wrapping the sample with cadmium foil or, as proposed by Berthelot et al.

Rev.52,

by mixing the sample with lithium salt.

Rhenium There

are

two

photon

reactions

of

rhenium

which

enable

excellent

activity

yields, namely those producing * 8 ®Re and * 8 4 R e , respectively. However, normally,

due to the extremely low natural abundance of the element, the sensitivity

of instrumental

photon

activation

analysis is insufficient.

186Re

can be

pro-

duced with one of the highest activity yields encountered in photon activation, but its gamma-ray energies are inconveniently

low

(123 and 137 k e V ) and not

v e r y abundant ( 1 and 12%, r e s p e c t i v e l y ) . Moreover, both lines most probably are subject to overlap interference in multi-component

spectra.

The other mentioned reaction product emits a more conveniently measurable gamma spectrum, but is produced with lower activity yield. In the case of rhenium analysis,

low

energy

fluorescence

yields

named product

photon spectrometry of

the

tungsten

does not o f f e r any improvement;

kX-ray

lines

associated

with

nuclides are about as low as the intensities of the

the

the

above

gamma-ray

lines. Moreover, since the X - r a y lines are emitted by both nuclides at comparable emission

probabilities

the decay curve is complex and one would have

to

wait f o r a long (more than one month) cooling period b e f o r e measurement to ascertain that * 8 ®Re has decayed out. As f a r as it is known to the authors, photon activation has not been applied to analysis of hafnium hitherto. Osmium Osmium can be analysed with fairly good sensitivity by or

183mOs

( h a l f - l i f e = 10 h ) .

185Re

produced by

186Οβ(γ,ρ)

( h a l f - l i f e = 94 d ) has also been used

(Segebade et al.*·'·', R e v . 1 0 9 ) . However, regarding the low natural abundance of

605 osmium,

the

intrinsic

sensitivity

of

instrumental

photon

activation

analysis

mostly is i n s u f f i c i e n t . Except the above quoted p a p e r by Segebade et a l . , no r e f e r e n c e about photon a c tivation analysis of osmium could be found by the a u t h o r s . S u r p r i s i n g l y , toexcitation

of the two analytically

usable isomeric

( 190m O s >

obviously was not applied to osmium analyses.

pho-

states 192m0s)

Particularly the former emits a

conveniently measurable gamma-ray s p e c t r u m . Oka et al. 1152

usecj

185q s

as

internal photon flux monitor in t h e analysis of

an

ruthenium in osmium-containing matrices. Several chemical compounds of osmium a r e easily volatilised,

t h e r e f o r e it is recommended to cool the analysed

samp-

les d u r i n g b r e m s s t r a h l u n g irradiation. I ridium Both the high e n e r g y gamma and the low e n e r g y photon spectrum of 190mj r ^ J J

usecj

190

I r and/or

f o r v e r y sensitive analyses of iridium (Segebade et al. 1®®,

R e v . 109). The gamma-ray s p e c t r a of both activation p r o d u c t s a r e conveniently measurable although some of the lines might be subject to overlap i n t e r f e r e n c e . The e n e r g y photon spectrum of

190

l r is partly overlapped by iridium k X - r a y s

emitted by l®lpt produced through photonuclear reaction of platinum

possibly

p r e s e n t in the sample. However, these i n t e r f e r e n c e s easily be accounted f o r . Breban et a l . 1 0 6 5 .

Rev .99, found several i n t e r f e r e n c e s of

most of them

originating from o t h e r Noble Metals which were highly concentrated in t h e a n a lysed samples. Iridium

can also be analysed

with excellent

sensitivity and selectivity

photoexcitation of t h e l 9 l m l r level (Otvos et a l . 2 1 1 , Lukens et a l . 1 2 1 . Lukensl24,

using

Rev.23,

Rev.24, Engelmann and J e r o m e * 2 2 and o t h e r s ) .

Platinum T h e r e a r e several photonuclear reactions of platinum yielding fairly high a c t i vities,

but

t h e i r product

nuclides emit gamma-ray lines which a r e located in

inconveniently low e n e r g y regions a n d / o r have poor intensities (l 9 "* m Pt, 195 m pt, 1 Q7 P t ) . T h e r e f o r e , low e n e r g y photon spectrometry is recommendable, measuring the platinum k X - r a y emission due to internal conversion of 193mp t

ancj

195mp^

tQ

the ground level. Both nuclides c o n t r i b u t e to the common signal in comparable

606 amounts, hence t h e decay function is complex. However, the half-lives a r e similar (4.33 d and 4.02 d, r e s p e c t i v e l y ) , so that one can assume an a v e r a g e halflife .without inducing excessive e r r o r . Major i n t e r f e r e n c e , however, is due to 1 Qfi Au produced by gold probably p r e s e n t in the sample giving also rise to platinum X - r a y s with extremely high fluorescence yields. Breban et a l 1 0 6 5 , Rev.99, used the 99 keV gamma-ray line of

195m

35 MeV b r e m s s t r a h l u n g activation of Black Concen-t r a t e s ;

they found multiple

p t produced by

i n t e r f e r e n c e b y adjacing and overlapping gamma-ray p e a k s . Segebade et a l . , see Ref's.

1072f R e v . i o 9 , used both gamma- and X-ray s p e c t r o s c o p y to meas189

u r e the various emissions of

Pt,

1

9 3 m p t , 195m p t

and

197 p t

in

bremsstrahlung

activated electrolytic c o p p e r . 195m p t

pro

R e v . 9 9 ) . If l a r g e r amounts of gold a r e p r e s e n t in instrumental photon activation analysis is of p a r t -

icular a d v a n t a g e since the problem of matrix-caused attenuation of the a c t i v a t ing beam is not a s serious as in thermal neutron activation (see above,

Para.

6 . 2 . 3 . 4 ) . Moreover, s e l f - a b s o r p t i o n of the measured gamma e n e r g y mostly is negligible in i n s t r u m e n t a l photon activation analysis since

also emits

607

high e n e r g y

gamma-rays

( e . g . 1091 k e V ) , 1 qo

photon e n e r g i e s emitted (Lutz717,

Reimers

et

by

w h e r e a s 411 keV is the highest of all

Au p r o d u c e d

al.884,

Rev.118).

through

thermal neutron

Additionally,

the

p r o d u c e d t h r o u g h photon activation is more c o n v e n i e n t than that of compared

with 2.7 d ,

method

large

series

Ref.1160,

has of

very

sensitively

been

frequently

o r e and

mineral

applied

by isomeric state

for

samples in the

R e v . 8 9 , Kapitsa et a l . 2 8 3 ,

The

( s e e also

behaviour

gold

is

of

thin

present

if

the

as

a

t h r e s h o l d of radiation

gold

sive

dead

time

was i n v e s t i g a t e d

major

electron

197Au

of

(6,2 d

photoexcitation.

Soviet

Union

(Pchelkin

gold et

in

al.,

R e v . 9 6 , B u r m i s t e n k o 1 1 9 1 and many o t h e r s ) .

gold l a y e r s on aluminium

t h r o u g h photon a c t i v a t i o n . complex

198Au

p r o d u c e d in a nuclear

selenium).

with 44 MeV b r e m s s t r a h l u n g

If

196Au

fast r o u t i n e a n a l y s e s of

A k b a r o w et a l . 1 9 5 used excitation by gamma-rays from reactor

of

respectively).

Gold can also been analysed This

activation

half-life

component

(23.2 M e V ) .

of

the

during

an

intense

bombardment

al.1198»1199.

background

is

created

T h e gamma component of this b a c k g r o u n d is not v e r y

energy

objects

substrate

by Eschbach et

of

the

was

set

below

the

(γ,3η)

H o w e v e r , e x p e r i m e n t s have shown that a f t e r i r -

the matrix

gamma

accelerator

radiation

counting

emitted

equipment

by

so

1 9 ®Au

that

the

causes

exces-

results

of

the

analysis of o t h e r components might not be r e l i a b l e .

Mercury

The

photonuclear

data of m e r c u r y οη*}

al photon activation a n a l y s i s . sis

evaluation.

but

The

latter

has an i n c o n v e n i e n t l y

Hg and

is

produced

short

radiation.

high

b r e m s s t r a h l u n g activation

of

the i n t e r f e r e n c e

sources

s t a n c e : 279 keV from ted by

2®3Pb

can

be

for

instrument-

higher

activity

thus it might

usable

than

the

be swamped

gamma-ray

lines

former,

by

matrix

emitted

after

a r e subjet to o v e r l a p i n t e r f e r e n c e .

discarded

by

long

cooling

periods,

Some

for

in-

mostly is i n t e r f e r e d by the same gamma e n e r g y emit-

p r o d u c e d by lead which is f r e q u e n t l y p r e s e n t in the a n a l y s e d sam-

ple at

considerably

203Hg

(46.6

d)

l i f e = 52.1 h ) circumvent

2"3Hg

analytically

sensitivity

Hg have mostly been used f o r a n a l y with

half-life;

background energy

All

indicate excellent ι qπ

higher

concentrations

allows a decay probably

has d e c a y e d

interferences

A t r i and S e g e b a d e 8 9 6 ,

than

mercury.

to n e g l i g i b l e l e v e l .

is the use of low e n e r g y

Rev.79).

T h e long

time of say one month a f t e r which

photon

Another

half-life 203Pb

possibility

spectrometry

of

(halfto

(Raghi-

608 R i c c i 9 7 4 used the 192 keV gamma-ray line of activation with 105 MeV b r e m s s t r a h l u n g . found

199m

197

H g for mercury analysis a f t e r

Chattopadhyay et

a i.330,883 (

Rev.40,

H g , being produced with the highest yield among all nuclides g e n e r -

ated in photon activated m e r c u r y , i n t e r f e r e d by

123m

analysis. T h e y used the 134 keV conversion line of

S n and hence not usable f o r 197m

Hg.

1 1 fil Gerstenberger

used instrumental photon activation analysis f o r t h e d e t e r m -

ination of the a b u n d a n c e s of several stable mercury isotopes. However, t h e major problem in the analysis of mercury surely is not t h e lack of intrinsic and

sensitivity

of

the

method;

many o t h e r t e c h n i q u e s ,

meet the sensitivity 6.2.4.3,

behaviour

of this element. under

photon

requirements of mercury analyses.

paragraph compounds

instrumental

activation

analysis

thermal neutron activation in p a r t i c u l a r ,

mostly

As was discussed

major attention has to be directed to the

physicochemical

It is not only the overall instability of

h e a t - and radiation attack d u r i n g activation

in

which

mercury creates

serious problems - although these surely a r e the major ones. The trouble s t a r t s with the sampling and sample storage prior to analysis. Takeuchi et a l . , 1 1 ® 2 and1163, and

-

in thermal neutron activation c o n t e x t , recommended to store samples in

the

interest

levels - particularly

of

long-term

stability

of

the

mercury

concentration

r e f e r e n c e materials at -20°C before and a f t e r activation.

At this point it is i n t e r e s t i n g to note that none of the above cited

authors

evaluated the volatility problem in photon activation. As f a r as it is known to t h e a u t h o r s , t h e r e a r e but two p a p e r dealing with t h i s problem in b r e m s s t r a h l u n g activation context (Raghi-Atri and Segebade® 9 ®, Rev.79,

Segebade® 9 3 ).

T h e r e a r e s e v e r a l sampling t e c h n i q u e s which p r e v e n t reliable and r e p r e s e n t a t i v e r e s u l t s of the analysis a priori,

e.g.

the sampling of mercury in air p a r t i c -

ulate on a i r - d u s t f i l t e r s . Assuming that a major p a r t of the a i r b o r n e mercury lies b e f o r e as p u r e

element,

this

fraction whose concentration is

dependent

upon many p a r a m e t e r s will be volatilised by s u b s e q u e n t air-flow, and finally, only v e r y stable mercury compounds ( e . g . mercury sulphide) will be collected entirely. In the sample preparation s t e p , mercury losses can occur d u r i n g high t e m p e r a t u r e d r y i n g of t h e sample. This is particularly t r u e in organic matrix. In o r g a nic environment, the mercury most likely is organically bound, e . g . as methyle mercury (Wood et a l . 1 1 6 4 · 1 1 6 5 ,

Ridley et a l . 1 1 6 6 ,

DeSimone 1 1 6 7 ) which is e x -

tremely volatile and significant losses have been stated d u r i n g sample p r e p a r ation t e c h n i q u e s like d r y i n g and a s h i n g , even at low t e m p e r a t u r e s ; also d u r i n g

609 f r e e z e - d r y i n g it might happen that not all mercury is retained (Litman et a l . , Ref.1168).

However, the most critical phase in this instance is the irradiation

s t e p . A systematic s t u d y of the volatility behaviour d u r i n g b r e m s s t r a h l u n g e x posure

of

Segebade,

several

elements,

mercury

in

particular,

was

undertaken

by

Ref.893.

Many similar investigations were published , a s touched on above, in the neutron activation context; some of these p a p e r s and the measures against mercury losses proposed therein a r e now summarised: Brune et a l . 1 1 ® 9 - 1 1 7 1 and o t h e r workers s u g g e s t irradiation at low

(-40°C)

t e m p e r a t u r e s . This can be accomplished much more conveniently d u r i n g accelerato r activations than - as was r e p o r t e d in the quoted p a p e r s - in nuclear r e a c t ors.

See also - in a d i f f e r e n t oontext - R e f . 1 1 ^ .

Bate 1 1 '''* found significant

losses of mercury from sealed plastic irradiation containers and sealing

the samples in q u a r t z vials.

a u t h o r s ( e . g . Rook et a l . 1 1 7 3 ,

recommended

This was reported also by many

other

Sjöstrand1174).

The addition of s t r o n g inorganic acids or oxidising a g e n t s minimises loss of mercury from plastic irradiation containments a s found by McFarland 1 1 7 ®. However, all t h e s e methods a r e associated with considerable p r o c e d u r a l e f f o r t . A more elegant way is t o " t r a p " the mercury chemically with help of a p p r o p r i a t e compounds. Takeuchi et al. 1162,1163 m i x e ( j s u l f u r compounds like thiourea, Lcystein, thioacetamide and ammonium sulphide with t h e sample p r i o r to i r r a d i a t ion. By t h e s e chemicals, mercury which is set f r e e by heat and radiation e n e r gy, is caught and t r a n s f e r r e d into heat- and r a d i a t i o n - r e s i s t e n t HgS. RaghifiQfi Atri and Segebade

, Rev.79,

used LiHS for mercury fixation d u r i n g photon

activation. Experiments of both groups have indicated stability of the mercury c o n t e n t s both d u r i n g and a f t e r (by eventual radiolytic reactions) activation. Particularly

in

photon

additional background

activation

analysis

this

method

is suitable

radiation is created by lithium sulphide.

described t r a p p i n g method b e a r s the d a n g e r of contamination;

since

However,

no the

t h e r e f o r e it is

recommendable t o r u n chemicals blanks along with t h e samples to be a n a l y s e d . Thallium Thallium is one of t h e elements which a r e v e r y well determinable by i n s t r u m e n t al photon activation analysis compared with o t h e r i n s t r u m e n t a l t e c h n i q u e s .

Un-

610

like thermal n e u t r o n a c t i v a t i o n , conveniently activity.

measurable

(half-life

(half-life long

nuclide

photon irradiation

(2"2T1)

produced

=

13.9

= 12.2

cooling

sensitivity Rev.52).

by

is

the

will

have

decayed

be measured

not allowed,

mercury

kX-ray

can

easily

i n t e r f e r e n c e by

specific

lines

accounted

negligible

can

due

If,

202

T1

for any r e a s o n ,

a

be a n a l y s e d

to

2

"2T1

and

with

quasi-equal

(Berthelot

by thallium k X - r a y for.

activity

signals,

A theoretically

et

al.1005,

but this i n -

possible

first

order

P b ( y , n p ) has been d i s c u s s e d ; Masters and L u t z * " " 1 and Hislop

204

and W i l l i a m s 1 0 2 7 ,

be

to

interference-free.

thallium

These are partly overlapped

terference

high

by 439 keV from

but a f t e r a cooling period of say one w e e k , t h i s n u c -

h)

d) can

period

gives rise to a

with

T h e 440 keV gamma-ray line most likely is i n t e r f e r e d

®^ m Zn produced by z i n k , lide

high-energy

product

Rev.65,

did not d e t e c t a n y c o n t r i b u t i o n of

and K a t o 1 1 4 2 and C h a t t o p a d h y a y et a l . 3 3 0 ' 8 8 3 , t e r f e r e n c e by i r r a d i a t i n g at lower e l e c t r o n

202

T 1 by l e a d . Oka

R e v . 4 0 , minimised an e v e n t u a l i n -

energy.

Lead In

reviewing

the

literature

about

photon

activation

lead to be one of t h e most studied e l e m e n t s . this

element

can

be

this

readily

analysis

is due to t h e

determined

whereas

fact

during

that

-

analysis,

one

will

find

B e s i d e s the g e n e r a l importance of as in

instrumental

t h e c a s e of thallium -

multielement

this cannot be accomplished e . g .

photon

lead

activation

by thermal neutron

activat-

i o n . At b r e m s s t r a h l u n g e n e r g i e s up to 40 MeV two p r o d u c t nuclides a r e s u i t a b l e for lead a n a l y s i s , 204mpb-

A t

namely

2

"3Pb

but

regarding

lytical

its

short

might a r i s e sensitivity

T h e gamma-ray lines of

half-life

(66.9

m)

in

due to e v e n t u a l e x c e s s i v e

using

either

product

nuclide

204m

P b a r e not i n t e r f e r e d ,

multi-component background is

very

i n t e r f e r e n c e is not p o s s i b l e at a c t i v a t i n g b r e m s s t r a h l u n g οηο 80 MeV.

T h e 279 keV gamma-ray line of

e n e r g y of

and

b r e m s s t r a h l u n g e n e r g i e s of not l e s s than 25 MeV, both a r e produced

with about equal a c t i v i t i e s . ficulties

(which has been used t h e most f r e q u e n t l y )

203

H g or

matrices

activity.

good and

The first

difanaorder

e n e r g i e s of up to say

Pb might be i n t e r f e r e d

by t h e same

' H g produced by m e r c u r y , but normally t h i s i n t e r f e r e n c e

iM m

may be n e g l e c t e d . At l a r g e c o n c e n t r a t i o n s of barium in t h e sample, 276, 278 and 274 keV peak.

from

133m

Cs

and

136

Cs,

respectively,

7

®Se (280 keV)

produced

p a r t l y o v e r l a p t h e lead

p r o d u c t s might also i n t e r -

by selenium, t h e same e n e r g y

produced by s i l v e r a n d / o r cadmium and 282 keV from

bromine. larger

129

Gamma-ray lines from s e v e r a l o t h e r activation

f e r e , among them ^^Ag,

Ba,

If one or

more of t h e

concentrations,

203

Pb

can

named as

elements

are

well be a n a l y s e d

77

present by

the

from

B r produced by

in the sample in thallium

kX-ray

emission using low e n e r g y photon s p e c t r o m e t r y with a b o u t t h e same s e n s i t i v i t y

611

as achievable using conventional gamma spectrometry. This radiation is not s e r iously i n t e r f e r e d . Poor sensitivity

for lead using instrumental photon activation analysis with a

betatron was stated by Brune et a l . 2 4 " . A f t e r 140 MeV bremsstrahlung activation,

Ricci®' 4 found greater sensitivity using ^"^Pb than by 204mpjj ^y

of more than t w e n t y - f i v e . other

analysts

of

Toronto usually 2"3Pb,

might

Chattopadhyay et al.

photon

preferred

f e r e n c e . However, used

the

activation

2"4mpb

330>883>991,

analysis

group

factor

a

Rev.40, and many

of

the

University

of

because of its freedom from spectral inter-

if v e r y small concentrations of lead had to be analysed they

eventually

be the inconstant

after

a radiochemical

separation.

A

source

of

error

natural isotopic composition of lead (Hislop and P a r -

ker1037).

The

stability

paragraph

behaviour

6.2.4.3

of

lead

(subparagraph

during

activation

was already

discussed

on elements of particular biological

in

interest

at the end of the p a r a g r a p h ) . Most lead compounds have been found relatively stable

against

there

are

used

as

heat and

several an

radiation

volatile

automobile

during

compounds

gasoline

of

additive.

bremsstrahlung lead, This

in

exposure.

particular is

easily

However,

tetraethyle

volatilised

lead

during

activation and hence analytical results might be erroneous. Moreover, a systematic e r r o r can also be introduced already in the sampling step, e . g . during air particulate collection on

filters

as has also been observed in the case of mer-

cury (see a b o v e ) . If lead is a major matrix component it creates an intense background after activation

and longer cooling periods might be necessary

radiation

prior to meas-

urement of other activities. Bismuth Bismuth can be analysed by instrumental photon activation analysis using

2 ® 6 Bi

( h a l f - l i f e = 6.24 d ) . However, the major gamma-ray lines (803 and 881 k e V ) f r e quently are subject to overlap interference by l ° 6 m A g

^ e V ) and

84Rb

(881

k e V ) . Moreover, at 30 MeV electron e n e r g y , the sensitivity is rather poor since the nuclide is produced by a ( γ , 3 η ) reaction which has a relatively high a c t i v ation

threshold

(22.3 MeV)

and,

correspondingly,

a relatively

low

effective

activation cross section (168 MeV-mbarn,

see W y c k o f f 1 1 7 6 ) ; these data are com19 parable to those of the ( γ , η ) reaction of C (see 6 . 1 . 4 . 1 ) . T h e r e f o r e , it is recommendable to use higher bremsstrahlung energies (about 40-45 M e V ) . No

612 111 ft first order

interference

is

possible,

whatsoever.

at 50 MeV a n d f o u n d almost equal s e n s i t i v i t y 203

using

Pb.

Sato

209

irradiated

for b i s m u t h u s i n g

T h i s is due to the low isotopic a b u n d a n c e of

compared with 100% of he calculated

Lutz and

204

a n d lead Pb

(about

1.4%

B i ) . C h a t t o p a d h y a y 3 3 0 used the 803 keV g a m m a - r a y line;

the c o n t r i b u t i o n

1

of

"®mAg

to this peak a n d s u b t r a c t e d

it from

the common peak i n t e g r a l . C h a t t o p a d h y a y a n d J e r v i s ® " 3 , R e v . 4 0 , a n a l y s e d bismuth u s i n g both the c o r r e c t e d 803 keV line a n d the 881 keV p e a k ; s u r p r i s i n g l y obviously

did not detect a n y i n t e r f e r e n c e b y

they

T h i s is remarkable since r u -

bidium u s u a l l y is r a t h e r a b u n d a n t in the a n a l y s e d soil matrix. F i s s i l e elements At and

this

point

the application

of

photon

activation

to the a n a l y s i s

u r a n i u m is d i s c u s s e d ; as far as it is known to the a u t h o r s ,

of

thorium

neither other

instable elements up to u r a n i u m (technetium, prometium a n d the elements b e y o n d b i s m u t h ) nor the t r a n s u r a n i u m elements h a v e been s t u d i e d u s i n g photon a c t i v a t ion as y e t .

Nuclear duced

fuel material i n c l u d i n g photofission

al.1177,

and

Franks^7®).

plutonium

subsequent However,

was a n a l y s e d

in t h i s c h a p t e r ,

by

bremsstrahlung-in-

(Bramblett69,

neutron counting

Beyster

o n l y a n a l y s e s associated

et

with

photon c o u n t i n g are reviewed a n d t h e r e f o r e the mentioned p a p e r s are e x c l u d e d from f u r t h e r The

discussion.

analytical

use

of p h o t o n u c l e a r

reactions

induced

by

high

energy

brems-

s t r a h l u n g i r r a d i a t i o n of thorium a n d u r a n i u m has not been s t u d i e d v e r y often as y e t , a l t h o u g h the analytical potential - at least for u r a n i u m - is g r e a t . T h o r i u m can be a n a l y s e d u s i n g

231

Th

(half-life = 25.6 h ) . H o w e v e r , t h i s nuclide

emits an u n f a v o u r a b l e photon s p e c t r u m ; the only usable lines have low e n e r g i e s (13, 17, 26 a n d 84 k e V ) a n d poor a b u n d a n c e s . M o r e o v e r , most of them are subject to i n t e r f e r e n c e ,

mainly

not

the

included

in

due to p h o t o f i s s i o n

systematic

study

products.

presented

in

mentioned at this point since it was a n a l y s e d u s i n g

Therefore,

Ch.5

of t h i s

thorium book;

photon activation

was it

is

by o t h e r

workers. Berthelot et a l . 1 0 0 5

used the 84 keV line a n d so did H e r n a n d e z a n d

after activation with 20.5 MeV b r e m s s t r a h l u n g of a m i c r o t r o n .

Belov1179

613

Uranium can be analysed much more advantageously. The most abundant reaction with say 30 MeV bremsstrahlung, namely uranium determinations. evaluation. nuclides

However,

(Segebade

The

2^8U(y,n)2^7U

allows extremely sensitive

208 keV gamma-ray line can be used for analysis

this line is subject

and Fusban®"®,

to multiple interference

Rev.49).

by

several

The low energy photon emission

(59.54 keV gamma-ray e n e r g y and the neptunium kX series) o f f e r more sensitivity and is relatively free from interference. Segebade and Fusban found a detection limit of 5 ng using the 59. 54 keV line measured by low energy photon spectrometry.

Berthelot et a l . 1 0 " 5 used the neptunium k X - r a y line at 99.43 keV after activation with 40 MeV bremsstrahlung and found a detection limit of 28 n g .

Larger

concentrations of fissile material in the sample can give rise to inter-

ference,

by

photofission,

with

several

product

nuclides

used

for

analysis.

Segebade and Fusban (see a b o v e ) suggested to irradiate at 16 MeV electron e n e r g y if

more than 50 micrograms per gram of total fissile material is present in

the analysed sample.

615 Bibliography

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1200

Yu.

A.

Overman, R . T . , C l a r k , Η. M.

I s o t o p e n p r a x i s 17 ( 1 9 8 1 ) ,

Nukleonika 13 ( 1 9 6 8 ) ,

Trans.

241

581

Amer. Nucl. S o c . j?2 ( 1 9 7 9 ) ,

200

I n o r g . Nucl. Chem. j}6 ( 1 9 7 4 ) , 1

641

61

I n s t r . Meth. 168 ( 1 9 8 0 ) ,

169

"Radioisotope T e c h n i q u e s " , McGraw - Hill Book C o . , New Y o r k , 1960, C h . 2 - S e i t e ? -

1201

Nguyen Van Do, T r a n Due T h i e p , T r u o n g Thi A n , T r a n Minh D u e , Han Ngoc Cuong

Radiochem.

Radioanal. L e t t e r s 107 ( 1 9 8 6 ) ,

29

1202

Nguyen Van Do

Radiochem.

Radioanal. L e t t e r s 107 ( 1 9 8 6 ) ,

39

1203

Sato,

Radiochem. R a d i o a n a l . L e t t e r s 8 ^ ( 1 9 8 4 ) ,

1204

S h t a n , A.

1205

Griepink, Β . , Muntau, H.

Fresenius'Zeitschr.

1206

Vagi, M . , Masumoto,

Journ.

Τ. S.

K.

141

P r o c e e d . Panel on Nucl. T e c h n i q u e s in G e o c h e m i s t r y and G e o p h y s i c s , IAEA W i e n / Ö s t e r r e i c h , Nov. 25 - 2 9 , 1974, p . 1 2 9 Anal. Chem. 326 ( 1 9 8 7 ) ,

R a d i o a n a l . Chem. 109 ( 1 9 8 7 ) ,

237

414

Subject

Index

a b u n d a n c e 385,398 - , i s o t o p i c 399,442,611 a c c e l e r a t o r , c i r c u l a r 59,68ff - , cyclic 59ff - , electron 59ff,72 - , ion 59,61 - , l i n e a r 59,61ff - , static 59ff,70 a c c e l e r a t o r t u b e 64ff a c c e l e r a t o r n e u t r o n s , see a c t i v a t i o n a n a l y s i s with a c c e l e r a t o r n e u t r o n s accuracy 404,408,457,467f,479,492 a c t i v a t i o n a n a l y s i s with a c c e l e r a t o r neutrons 31ff,54f,84ff - with c h a r g e d p a r t i c l e s £ , 9 , 3 9 0 , 4 0 9 - with h e a v y ions 9 - with n u c l i d e - p r o d u c e d n e u t r o n s 7 - with p h o t o n e u t r o n s 5 4 f f , 1 6 6 , 1 7 0 , 3 3 3 , 361,406ff,412,441,445,450,459,519, 597ff,603 - with r e a c t o r n e u t r o n s 7 , 4 0 1 f f , 4 5 9 , 466,469,483,529,577,596 - with 14 M e V - n e u t r o n s 7 , 4 0 5 , 5 1 8 a c t i v a t i o n t h r e s h o l d , see t h r e s h o l d energy a c t i v a t i o n y i e l d , see y i e l d , a c t i v . a c t i v e volume 101,128,134 a d d i t i v e i n t e r n a l s t a n d a r d , see internal standard, additive a e r o s o l f i l t e r 358,389,455ff air particulate 410,455ff,547,581 alcaline e a r t h s 372 alkali metals 3 4 0 f f , 3 7 2 f f , 3 8 2 , 3 8 5 f a l p h a r a d i a t i o n 9,93 alumina 344ff aluminium 1 7 1 , 3 0 6 , 3 2 4 , 3 4 3 , 3 6 3 , 3 7 6 , 3 8 3 , 389,392,411,481,514,545 americium 7 a m p l i f i e r , see s p e c t r o s c o p y a m p l i f i e r a n a l o g - t o - d i g i t a l c o n v e r t e r (ADC) 144ff, 150f a n a l y s e r , see d i f f e r e n t i a l d i s c r i m inator; multichannel analyser a n n i h i l a t i o n r a d i a t i o n , see p o s i t r o n annihilation a n t i - C o m p t o n s p e c t r o m e t e r 133,145,484 antimony 188,199,308,381,454,464,472, 481f,486,501f,514f,527f,539,542,545, 547,549f,554f,561,563,565,567,592f a r c h a e o l o g y see a r c h a e o m e t r y a r c h a e o m e t r y 404,409,529ff

argon 359,363ff,376ff arsenic 176,196,307,324,347f,364,379, 390,393,464,466,472,481f,486,501ff, 514f,527f,539,542,545,547,549,554f, 563,565,567,581 a r t 529ff ascarite 339,343ff,373,376ff atomic a b s o r p t i o n s p e c t r o m e t r y (AAS) 403,459,462,469 atomic emission s p e c t r o m e t r y (AES) 462 A u g e r e l e c t r o n 95 automobile e x h a u s t see e x h a u s t , a u t o mobile background radiation 97,130,159f,326, 416,456,465,490,496f,504,520,522f b a c k s c a t t e r i n g s i g n a l s 113ff barium 1 8 4 , 2 0 0 , 3 0 9 , 4 0 6 , 4 5 1 , 4 5 4 , 4 6 4 , 4 7 2 , 481f,501ff,514f,517,519,527f,539,542, 545,549ff,554,563,567 b a s e l i n e r e s t o r e r 141 b a t h metal 337 beam a b s o r b e r 83 - a t t e n u a t i o n 78,403f - dump 83 - window 64,89 belt g e n e r a t o r , see a c c e l e r a t o r , s t a t i c beryllium 7 , 5 7 , 9 3 , 1 7 1 , 3 1 5 f , 3 2 3 , 3 3 6 f , 352,358,362f,372,389,392,401,568 beta r a d i a t i o n 1 0 9 f f , 1 1 5 , 3 1 3 , 4 0 1 - s p e c t r o s c o p y 313,315f,384 betatron 59,62,68ff,389,446,486,498, 507,518,591,611 biased a m p l i f i e r , see g a t e d biased amplifier binding energy 31,95,43ff biological material 3 8 9 , 4 1 1 , « O f f bismuth 193,212,310,337,348,372,401, 458,472,481f,486,502,515,539,543, 556,61If Black C o n c e n t r a t e 5 1 7 , 5 1 9 , 5 5 9 , 5 8 7 f , 6 0 6 blood 4 6 1 , 4 8 4 f f , 4 9 8 bone 3 5 8 , 3 9 6 , 4 8 5 f , 4 9 4 f b o r e c o r e 470f,511 boron 1 6 2 , 3 1 5 , 3 8 9 , 4 0 1 b r a s s 534f,560f b r e m s s t r a h l u n g continuum 29,59ff,74ff, 115 - converter 64,70,74ff,411,460,491, 498f - e f f i c i e n c y 78ff bromine 1 7 7 , 1 9 6 , 3 0 7 , 3 3 9 , 3 9 6 , 4 5 1 , 4 5 4 , (continued next page)

698 circular a c c e l e r a t o r , see a c c e l e r a t o r , circular coal 3 3 7 , 4 7 2 f , 4 7 6 , 5 2 4 , 5 6 6 f cobalt 1 7 4 , 1 9 5 , 3 0 7 , 3 4 6 , 3 6 6 f , 3 7 8 , 4 6 4 , 472,481f,501f,514f,521,527f,539,542, 545,547,549ff,554f,563,567,577 cadmium 1 8 1 f , 1 9 8 f , 3 0 8 , 3 2 3 , 3 5 0 , 4 0 1 , 4 4 0 f Cockcroft-Walton generator 59 451,464,466,471f,481f,486,501f,514, coherent scattering 96 528,542,545,547,552,554,563f,567, coinage 530,533ff,560 589f coincidence unit 1 5 5 , 3 1 6 , 3 2 5 , 4 8 5 , 5 1 1 f - shield 4 6 7 , 4 8 7 , 4 8 9 , 5 1 9 , 5 6 9 , 5 7 4 , colorimetry 459,570 576,580,601,604 coke 528 caesium 1 8 4 , 2 0 0 , 3 0 8 , 3 3 7 , 3 5 0 , 3 7 2 , 3 7 5 , 381,385,464,472,481f,486,501f,514, combustion 337ff,343ff,461 5 2 7 f , 5 3 9 , 5 4 2 , 5 4 5 , 5 4 9 f f , 5 5 4 f ,563, competing reaction, see i n t e r f e r e n c e , 565,567,594f nuclear calcium 1 7 2 , 3 0 6 , 3 6 0 , 3 6 4 f f , 3 8 3 , 3 8 9 , 4 0 1 , complex decay, see interference by 434ff,464,472,481f,485f,501ff,514f, secondary decay 527f,542,545,547,549ff,554,563ff, compound nucleus 20 567,572 compressed air t r a n s p o r t , see pneumatic calibration, see energy calibration tube sample transport californium 7 Compton edge, see compton effect - effect 9 5 f , 1 1 2 f f , 3 3 0 candidate r e f e r e n c e material, see - radiation, see compton effect r e f e r e n c e material - s c a t t e r i n g , see compton effect carbon 3 0 6 , 3 1 7 , 3 3 6 f f , 3 5 9 , 3 8 9 , 4 5 7 , 4 6 5 , computer 9 4 , 1 4 7 , 1 6 0 , 1 6 4 , 4 1 5 , 4 2 5 , 5 2 1 481,485,545,568 contamination, see also radioactive carousel, see rotating sample posit, carrier 337,340,343ff,363ff,369,373, contamination conversion efficiency, see 376ff,390,392ff bremsstrahlung efficiency cathode-ray tube ( C R T ) , see display c a v i t y , resonant 71f - gain 149f central o r b i t , see electron orbit converter target , see bremsstrahlung ceramic material, see pottery converter cerium 1 8 5 , 2 0 1 , 3 0 9 , 4 6 4 , 4 7 2 , 4 8 1 f , 4 8 6 , c o n v e r t e r , see bremsstrahlung converter 501f,514f,527f ,539,542,546,549ff, cooling 7 9 , 3 1 8 , 4 8 4 , 5 0 9 , 5 9 4 , 6 0 8 f 554f,563,597f cooling period, see decay period certification 476f,522f copper 1 7 4 f , 1 9 5 , 3 0 7 , 3 2 3 , 3 4 0 , 3 6 7 , 3 7 6 , certified reference materials, see 378ff,383f,392,402,456,481f,501,514, 520ff,527,539,542,545,552,561,563f, r e f e r e n c e materials 578f characteristic X - r a y s , see X - r a y s , characteristic cosmochemistry 512f charge carrier 102,124 Coulomb barrier 44,96 charged particle radiation 43ff count rate 1 2 0 f , 1 3 0 , 1 3 4 chemical i n t e r f e r e n c e , see c o u n t e r , see detector i n t e r f e r e n c e , chemical counting efficiency, see detector efficiency - yield, see yield, chemical - period 164,168f chlorine 1 7 2 , 3 0 6 , 3 8 9 , 3 9 6 , 4 5 4 , 4 6 4 , 4 7 2 , - geometry 1 2 7 , 1 5 8 , 1 7 0 , 3 2 5 , 4 0 9 , 4 1 3 f , 48 I f , 4 8 5 , 5 0 I f f , 5 1 4 , 5 2 8 , 5 4 2 , 5 4 5 , 5 5 4 , 423,433,479 563ff,567,571 chromium 1 7 3 , 1 9 5 , 3 0 6 , 3 2 3 , 3 4 5 , 3 9 6 , 4 5 4 , crime detection, see forensic analysis cross section, absorption 20ff,401 464,472,481f,501ff,514f,521,527f, 539,542,545,547,549,551f,554,563, - , activation 2 0 f f , 3 5 4 , 3 5 8 , 3 7 2 , 3 8 4 , 567,575f 407,433,485,491 - , effective n f f , 3 9 9 , 4 1 8 bromine 4 6 4 , 4 7 2 , 4 8 1 f , 5 0 2 , 5 1 5 , 5 2 8 , 5 4 2 , 545,547,563,582f bronze 521,532,534 buncher 63

699

crucible 337ff,343ff,360 c r y o s t a t 131f,157 cyclic a c c e l e r a t o r , see a c c e l e r a t o r , cyclic - activation 453 cyclotron 8f,62,68 data handling 147ff,415ff - storage 146,148,415 dead time 121,150ff,331,408,414 decay c u r v e , see decay function - function 313ff,326ff,358,389,462 - period 14ff,164,516 deexcitation 26ff deformed nuclei, see prolate/oblate nuclei detection limit 343ff,363ff,376ff, 392ff,399,465,468,471 d e t e c t o r , bismuth germanate 98 cadmium telluride 107 - , caesium iodide 98,478 - , coaxial, see ion d r i f t - , diamond 107 gas ionisation 93 - , Geiger-Müller 93 - , germanium I Q l f f , 156f,218 - , mercury iodide 107 - , p l a n a r , see ion d r i f t - , portable 106f - , scintillation 94,97ff,325ff,445f, 495 - , semiconductor 94,101ff,452 - , Si (Li) lOlff - , sodium iodide, see d e t e c t o r , scintillation - , well-type 99,104,116,132,326,334. 451 (see also 4π-counting) detector cooling 101,105ff, 132 - efficiency 99,101,126ff, 134,154, 167ff,326,417ff,423,433 - e n t r a n c e window 99f,104,129,131 - geometry 99f,101,103f,128,131f - linearity 130f,134,158 - resolution l O l f f , 122ff,134,138, 156ff,414f,485 - shielding 97,110,114 deuterium 57,93,162 Dewar vessel 132f differential discriminator, see discriminator, differential digital offset 143,151 discriminator, integral 144 - , differential 144ff,148

display 147f,152ff distillation, see vapour distillation doughnut 68 d r i f t configuration, see ion d r i f t d r i f t - t u b e , see accelerator tube dwell-time, see multichannel scaling dynode 101 dysprosium 187f,203f,309,600 effective cross section, see cross section, effective efficiency, see detector efficiency electron a c c e l e r a t o r , see a c c e l e r a t o r , electron - beam c u r r e n t 66f - beam window, see beam window - c a p t u r e 51f,313 - cyclotron 72 - energy 59ff,74ff,418ff,433 - gun 63,67 - orbit 68ff,74 electronic noise 139,142 electropolishing 322ff emission probability 167ff - r a t e 417ff e n e r g y calibration 154,158 - g r a d i e n t , see homogeneity, activation - resolution, see detector resolution environmental analysis 132,454ff erbium 188,205,309,454,515,601 escape peak 9 6 f , l l l , 1 1 4 f , 1 7 0 f f e s t u a r i n e material 479 e t c h i n g , see s u r f a c e problems europium 186f,202,309 e x h a u s t , automobile 456,458ff,581 e x p o s u r e , see irradiation fast n e u t r o n s , see n e u t r o n s , fast fertiliser 480 field effect t r a n s i s t o r 139f f i r s t o r d e r i n t e r f e r e n c e , see i n t e r f e r e n c e , nuclear fissile elements, see photofission fission p r o d u c t s 394,474f f l u o r e s c e n c e , see X-ray fluorescence fluorine 306,317,339,358,388ff,453, 481,503,514,528,545 flux d e n s i t y , gradient 75ff,319,420f, 468 (see also homogeneity, activation) - , neutron 31ff,54ff,441 - , photon 15ff,441

700 f l u x material 3 3 7 f , 3 4 3 f f , 3 5 4 , 3 6 3 f f , 373,376ff - monitor 1 6 2 , 3 1 9 , 4 0 9 , 4 5 6 , 4 7 6 , 5 3 3 fly a s h 4 7 2 f , 4 7 6 , 5 4 1 f f forensic analysis 487f,529ff,537f fossile material 389,396,523 f r e e z e - d r y i n g 478,485,487,582,609 full e n e r g y s i g n a l 9 5 , 1 1 2 f f , 4 1 7 f f f u l l width a t half maximum (FWHM), s< detector resolution f u l l width a t t e n t h maximum (FWTM), see d e t e c t o r r e s o l u t i o n f u r n a c e , see heating f u s i o n , inert gas 339f,359,363ff - , oxidising 337ff,360,363ff - , reductive 359f,363ff,373f,376ff - , vacuum 359,363ff 4-Tr-counting 9 9 , 1 0 4 , 1 1 6 , 1 2 7 , 1 3 2 , 3 2 6 gadolinium 187,203,309,527,599f gallium 1 7 5 , 1 9 6 , 3 0 7 , 3 2 4 , 3 4 7 f , 364,379, 390,393,472,481,545,580 gamma s p e c t r o m e t r y 93ff - s p e c t r u m , see p u l s e - h e i g h t s p e c t r u gas-sorbant 339,343ff,354f,363ff,370, 373,376ff g a t e 147 g a t e d biased a m p l i f i e r 143,518 G e ( L i ) - d e t e c t o r , see d e t e c t o r , germanium g e o c h e m i s t r y 337,504ff germanium 175f, 1 9 6 , 3 0 7 , 3 2 4 , 3 4 8 , 3 6 4 , 379,401,451,454,472,481,528,539,545, 580f germanium d e t e c t o r , see d e t e c t o r , germanium g i a n t dipole r e s o n a n c e 2 2 f f , 3 3 6 , 3 5 2 , 356,468 g i a n t r e s o n a n c e , see g i a n t dipole resonance glass 475,526,537f,555 gold 1 9 2 , 2 1 0 , 3 1 0 , 3 2 3 , 3 5 0 , 3 9 3 , 3 9 7 , 4 2 2 , 451ff,514f,527f,539,558f,606f graphite 329,343ff,373 g r e y w e d g e a n a l y s e r 144 hafnium 189f, 2 0 7 , 3 0 9 , 3 8 1 , 4 5 1 , 4 5 4 , 5 1 5 , 520,602 hair 4 6 0 f , 4 6 8 , 4 8 3 f , 4 8 7 f f , 4 9 5 f halogens 162,339,397,477,481f heat e x t r a c t i o n , see f u s i o n heating 337,343ff,363ff,373,376ff, 457,467

h e a v y i o n s , see a c t i v a t i o n a n a l y s i s with h e a v y ions helium 363ff,376ff high f r e q u e n c y s o u r c e , see k l y s t r o n high p u r i t y germanium d e t e c t o r , see d e t e c t o r , germanium high p u r i t y material 358,389,522 high r e s o l u t i o n d e t e c t o r , see d e t e c t o r , semiconductor high v o l t a g e 9 8 , 1 0 1 f , 1 5 7 holmium 1 8 8 , 2 0 4 , 3 0 9 , 4 5 4 , 6 0 0 homogeneity, activation 78,318ff,403f, 420f,529f - , composition 3 1 9 , 4 0 3 f , 4 5 8 , 4 6 7 , 5 3 6 Hopcalite 3 4 0 , 3 5 4 , 3 7 7 , 3 7 9 f , 3 8 4 h y d r o g e n 162 i n - s t a c k a n a l y s i s 472f,481 i n - v i v o a n a l y s i s 486 i n c i n e r a t i o n e x h a u s t 472f indium 1 8 2 , 1 9 9 , 3 0 8 , 3 2 4 , 3 5 0 , 3 8 0 , 4 4 0 f , 451,472,481f,542,554,567,590f i n d u c t i v e l y coupled plasma s p e c t r o s c o p y ( I C P - A E S ) , see atomic emission spectroscopy i n d u s t r i a l p r o d u c t s 516ff i n e l a s t i c photon s c a t t e r i n g , see isomeric s t a t e i n e r t gas f u s i o n , see f u s i o n , i n e r t gas i n h e r e n t i n t e r n a l s t a n d a r d , see internal standard, inherent instrumental analysis 166,327ff,334ff, 358,371ff,388f,401ff i n t e g r a l d i s c r i m i n a t o r , see discriminator, integral i n t e g r a t e d e f f e c t i v e c r o s s s e c t i o n , see cross section, effective i n t e r - l a b o r a t o r y comparison a n a l y s i s 457ff,476f ,540ff i n t e r f e r e n c e , chemical 3 2 6 , 3 2 9 f , 3 5 2 f , 367f,382ff,396f - , nuclear 60,70,163,213,300,317f, 329ff,353f,368,384,388f,396f,402, 4 0 8 , 4 1 3 , 4 2 4 f f , 4 5 0 , 5 6 8 f f (see also i n s t r u m e n t a l a n a l y s i s ; multi-element analysis) - , spectral 159,213,329f,424f,432f, 568ff ( s e e also i n s t r u m e n t a l a n a l y s i s ; multi-element a n a l y s i s ) i n t e r f e r e n c e by s e c o n d a r y d e c a y 300, 398,402,425,433ff i n t e r n a l m o n i t o r , see i n t e r n a l standard

701

internal s t a n d a r d , inherent 319f,341, 343ff,351,361,375f,381f,384,404, 414,418ff,521,532,578,587,591,594ff additive 319f,405,414,463,470f, 478,577,585,599,605f i n t r i n s i c germanium d e t e c t o r , see d e t e c t o r , germanium iodine 1 8 4 , 2 0 0 , 3 0 8 , 3 7 2 , 4 0 1 , 4 0 6 f , 4 2 2 , 464,472,481f,501ff,528,542,545,554, 593f ion d r i f t 101,103,125 - a c c e l e r a t o r , see a c c e l e r a t o r , ion iridium 1 9 1 , 2 0 9 , 3 1 0 , 4 5 1 , 4 5 4 , 5 2 8 , 5 5 8 f , 605 iron 1 7 3 f , 1 9 5 , 3 0 6 f , 3 2 3 f , 3 4 5 f f , 3 6 4 , 366f,376f,379ff,392,454,464,472, 481f,501ff,514f,520,527f,539,542, 545,549ff,554,563ff,567,576f irradiation 14ff,20ff,89,162ff,167, 317ff,404,41Iff,427 - geometry 404,408ff,419ff,469,504 isomeric p h o t o e x c i t a t i o n , see isomeric state - state 10,19,21ff,27ff,53,57,444f, 451ff,484,499,517,519,581ff,588ff, 592,595f,601ff isotope n e u t r o n s , see n e u t r o n s , i s o t . - s o u r c e s , see r a d i o n u c l i d e s u r c e s isotopic a b u n d a n c e , see a b u n d a n c e , isotopic - exchange 373ff,386,411 k - c a p t u r e , see e l e c t r o n c a p t u r e kale 4 8 3 f , 4 9 0 f , 5 6 5 Kjeldahl s e p a r a t i o n 3 5 9 f , 3 6 3 f f , 3 6 9 f k l y s t r o n 62 lanthanum 185,201,309,481,597 lazy s u s a n , see r o t a t i n g sample position lead 1 9 3 , 2 1 I f , 3 1 0 3 3 7 , 3 4 9 f , 3 7 2 , 3 8 1 , 393,401,422,451,454,464,466,471, 481ff,486,495,501ff,514f,517,527f, 539,543,546f,549,552,554,561,563ff, 567,610f Life s c i e n c e s , see e n v i r o n m e n t a l analysis;archaeometry; forensic analysis light e l e m e n t s 9 f f , 5 1 , 1 2 8 , 1 4 6 , 3 1 3 f f , 485 limit of d e t e c t i o n , see d e t n . limit l i n a c , see a c c e l e r a t o r , l i n e a r line i n t e n s i t y , see emission probability

l i n e a c , see a c c e l e r a t o r , l i n e a r l i n e a r a c c e l e r a t o r , see a c c e l e r a t o r , linear - a m p l i f i e r , see p r e a m p l i f i e r ; spectroscopy amplifier l i n e a r i t y , see d e t e c t o r l i n e a r i t y ; analog-to-digital converter(ADC) liquid samples 4 0 2 , 4 0 5 , 4 1 0 f , 4 7 7 f f , 4 8 5 lithium 1 6 2 , 3 1 5 , 3 2 4 , 3 3 7 , 3 6 3 , 3 7 2 , 3 7 6 , 389,392,401,441, lithium d r i f t , see ion d r i f t live c o u n t i n g 150,414 low e n e r g y photon s p e c t r o s c o p y (LEPS) 51,101,104,125,129,156,161,163,194ff, 313,406f,413,423f,463,471,478,500, 523,557f,579ff,586,588f,591,594f, 597ff lutetium 1 8 9 , 2 0 6 , 3 0 9 , 4 5 1 , 4 8 1 , 6 0 2 f l y o p h i l i s a t i o n , see f r e e z e d r y i n g magnesium 171,306,323f , 3 4 3 , 3 4 7 , 4 0 1 , 4 5 4 , 464,472,481f,485,501ff,514f,527f,539, 542,545,549ff,554,563ff,567,569f manganese 173,195,306,401,464,472, 481f,501ff,514f,527f,539,542,545,547, 549f,552,554f,563ff,567,576 matrix absorption 93,313,319,328,398, 403,413,421f,424,463,517,596 - a t t e n u a t i o n , see matrix a b s o r p t i o n - composition 3 1 9 , 3 3 4 , 3 5 1 , 4 0 3 f , 4 2 2 f , 520,536 m e a s u r e m e n t g e o m e t r y , see c o u n t i n g geometry mercury 192f,211,310,359,411,422,451, 466,472,481ff,486,501ff,5421,546, 552,554,563,567,607ff metal r e f i n e r y e x h a u s t , see e x h a u s t , industrial m e t a l s , a n a l y s i s of 520,530 m e t e o r i t e m a t e r i a l , see c o s m o c h e m i s t r y microtron 59,70ff,517,521f,524,612 milk 495 mineral material 504ff mining 505,517ff m i x e r / r o u t e r 152 mode t r a n s f o r m e r 64 molecular sieve 359f,363ff molybdenum 1 7 9 , 1 9 7 , 3 0 8 , 3 2 3 f , 3 4 8 f ,365, 380,454,464,472,48 If,486,501f,514, 542,545,554,563,567,586f m u t i c h a n n e l a n a l y s e r (MCA) 9 4 , 1 4 4 f , 146ff,157,415f m u l t i c h a n n e l s c a l i n g 147,152 m u l t i d i s c r i m i n a t o r 144

702 molti-element a n a l y s i s 9 3 , 3 5 1 > 4 0 1 f f - s t a n d a r d , see r e f e r e n c e material mylar 3 5 1 , 3 8 2

peak s e a r c h 1 5 4 , 1 6 4 , 4 1 5 f p e a k - t o - C o m p t o n r a t i o , see s i g n a l - t o - C o m p t o n ratio p h a s e s h i f t e r 66 N - v a l u e 169ff p h o s p h o r , s e e scintillation phosphor neodymium 185f , 2 0 1 f ,309 phosphorus 1 7 1 , 3 1 6 , 3 4 7 , 3 5 0 , 3 6 4 , 3 8 0 , neon 397 481,545,570f neutron a c t i v a t i o n a n a l y s i s ( N A A ) , see photocathode 98f a c t i v a t i o n a n a l y s i s with n e u t r o n s photodisintegration 4 , 1 0 , 9 3 , 3 1 3 p h o t o e f f e c t , see p h o t o e l e c t r i c e f f e c t - capture 7 photoelectric effect 95,111,130 n e u t r o n s , fast 7f p h o t o e x c i t a t i o n , see isomeric s t a t e - , isotope 7 photofission 1 9 , 3 6 , 5 3 f , 1 6 6 , 3 1 5 , 4 7 4 f , - , p r o m p t , see prompt radiation - , thermal 6f ( s e e also activation 585,587,593,612f a n a l y s i s with r e a c t o r n e u t r o n s ) photomeson 26 - , 14 MeV 7 ( s e e also activation photomultiplier 9 4 , 9 8 f f a n a l y s i s with 14 M e V - n e u t r o n s ) photoneutron moderator 8 5 , 9 1 nickel 1 6 3 , 1 7 4 , 1 9 5 , 3 0 7 , 3 2 3 , 3 4 3 f f , 3 6 4 , - reactions 19,31ff 366,376ff,392,402,426,464,472,48 If, - spectrum 54 485f,501ff,514f,527f,539,542,545, p h o t o p e a k , see full e n e r g y s i g n a l 547,549ff,554f,561,563,567,578 photoproton 4 4 f , 3 3 3 , 3 5 4 , 3 9 7 f , 4 4 1 f , 4 4 5 niobium 1 7 9 , 1 9 7 , 3 0 8 , 3 2 4 , 3 4 8 , 3 6 5 , 3 7 9 f , pile-up 9 4 , 1 4 2 , 3 3 1 401,464,472,48If,539,545,549f,563, planar d e t e c t o r , see d e t e c t o r , planar 586 plant material 4 1 1 , 4 6 6 f f , 4 9 0 f f , 4 9 6 , nitrogen 3 0 6 , 3 1 7 , 3 3 9 , 3 5 8 f f , 3 7 7 , 3 8 9 , 500 396 p l a s t i c material 525 Noble G a s e s 162 platinum 1 9 1 f , 2 1 0 , 3 1 0 , 3 3 7 , 3 4 3 , 3 6 6 , 3 7 3 , Noble Metals 3 2 3 , 4 0 1 f , 4 0 9 , 4 5 2 , 5 1 6 f f , 377,379ff,393,451,527f,558f,605f 523,527f,531,533,539,557ff,605f Plutonium 612 n o n - d e s t r u c t i v e a n a l y s i s , see pneumatic t u b e sample t r a n s p o r t 8 9 f f , instrumental analysis 371,411,519 n u c l e a r i n t e r f e r e n c e , see p o l e / z e r o cancellation 141f i n t e r f e r e n c e , nuclear positron 5 1 , 1 1 5 , 3 3 6 , 3 7 1 , 3 7 7 , 3 9 8 - reactor 6,92,457,529 - annihilation 1 0 f , 5 1 , 9 6 f , 1 1 4 , 1 6 1 , 313ff, 325,328,336,414,468 o b l a t e nuclei 2 2 , 3 7 positronium 51 o p e r a t i n g v o l t a g e , see high voltage potassium 1 7 2 , 3 0 6 , 3 4 4 , 3 8 3 , 4 5 4 , 4 6 4 , 4 7 2 , ore 473,504,516ff,557f 481f , 5 0 1 f , 5 2 8 , 5 3 9 , 5 4 2 , 5 4 5 , 5 5 1 , 5 5 4 , o r g a n i c material 3 3 7 , 3 5 8 , 3 7 1 f , 3 8 9 , 4 0 1 , 563ff,567 403,411,422,480ff,562ff pottery 530ff,551 osmium 1 9 1 , 2 0 8 f , 3 1 0 , 4 5 1 , 5 2 8 , 5 5 8 , 6 0 4 f power a t t e n u a t o r 66f o x i d i s i n g d i s s o l u t i o n , see f u s i o n , - d i v i d e r , see power a t t e n u a t o r oxidising power station e x h a u s t , see - fusion, see fusion, oxidising incineration exhaust - melt 339f praseodymium 1 8 5 , 2 0 1 , 3 0 9 , 4 5 4 , 5 9 8 preamplifier 9 4 , 1 3 9 f oxygen 3 0 6 , 3 1 7 , 3 5 9 , 3 7 1 f f , 3 8 9 , 4 1 4 p r e c i o u s m e t a l s , see Noble Metals precipitation 397 pair production 96f precision 4 0 8 , 4 5 7 , 4 7 9 , 4 9 2 palladium 1 8 0 f , 1 9 8 , 3 0 8 , 5 2 7 f , 5 5 8 f , 5 8 8 preconcentration 390,397 p a r t i c l e size 460f primary s t a n d a r d 3 2 9 , 3 5 1 , 4 0 3 , 4 6 0 f f peak a r e a 1 5 9 f , 4 1 6 p r o c e s s o r 148 - assignment 158f,415f prolate nuclei 2 2 , 3 6 f - location 1 5 4 , 4 1 5 f

703 Promethium 162 prompt r a d i a t i o n 3 , 3 1 f f , 4 3 f f , 5 2 , 3 1 3 p r o t o n - i n d u c e d X - r a y emission ( P I X E ) 462 p u l s e s h a p i n g 142 pulse-height a n a l y s e r , see differential discriminator;multichannel analyser(MCA) - spectrum 95ff,102,109ff

rubidium 1 7 7 , 1 9 6 f , 3 0 7 , 4 5 4 , 4 6 4 , 4 7 2 , 4 8 1 f , 501ff,514f,527f ,539,542,545,549ff, 554f,563ff,567,583 ruthenium 1 7 9 f , 1 9 7 f , 3 0 8 , 5 2 7 f , 5 5 8 , 5 8 7

samarium 1 8 6 , 2 0 2 , 3 0 9 , 4 0 6 f , 4 6 4 , 4 7 2 , 4 8 1 , 546,549,598f sample c a p s u l e , s e e sample r a b b i t - geometry, see irradiation geometry; measurement geometry - preparation 321f,410ff,608f quantitative evaluation 416ff - rabbit 89,411 q u a s i - d e u t e r o n e f f e c t 26 - t r a n s f e r , s e e p n e u m a t i c t u b e sample transport r a d i a t i o n damage 8 2 f , 3 1 8 , 3 3 5 , 4 0 3 , 4 2 2 , 458,462,469,484,491f,498f,504 - volume 402 - detector, see detector sandwich geometry 4 6 2 , 4 9 1 , 5 0 6 , 5 1 1 , 5 1 7 - protection 3 , 3 3 5 , 4 2 2 s a t u r a t i o n a c t i v i t y 516 radioactive contamination 9 7 , 3 1 9 , scandium 1 7 2 , 3 0 6 , 4 0 6 f , 4 6 3 , 4 7 0 f f , 4 7 8 , 481f,515,539,542,545,549,551,554, 321ff,355,370,374,383f,402,422 563,567,573 radiochemistry 92,313ff,495 S c h m i t t - t r i g g e r , see discriminator, r a d i o l u m i n e s c e n c e 112 r a d i o n u c l i d e photon s o u r c e s 1 0 , 5 7 f f , integral 451,583,589,591,601,603,607 Schütze reagent 339f,354 - neutron s o u r c e s , see n e u t r o n s , scintillation d e t e c t o r , see d e t e c t o r , isotope scintillation Rare Earths 402,454,521,596ff - p h o p h o r 98 raw p r o d u c t s 5 1 6 f f s e c o n d a r y d e c a y 213 ( s e e a l s o i n t e r r e a c t o r , see nuclear reactor f e r e n c e by s e c o n d a r y d e c a y ) recoil activity 3 1 9 , 3 3 3 , 4 1 1 , 4 2 2 , 4 7 8 - electron emitter, see photor e d u c t i v e fusion, see f u s i o n , r e d u c t i v e multiplier r e f e r e n c e material 1 1 , 1 5 8 , 3 2 9 , 3 4 3 f f , - reaction 332f 351f,361ff,370,376ff,382,396,416ff, - s t a n d a r d , see r e f e r e n c e material 4 5 7 f f , 5 4 0 f f ( s e e also i n s t r u m e n t a l / s e d i m e n t , see w a t e r - r e l a t e d material multi-element a n a l y s i s ) selectivity 352,412,505,509 - pulser 155,419 selenium 1 7 6 , 1 9 6 , 3 0 7 , 3 2 3 , 3 4 8 , 3 7 3 f 3 7 9 , r e f r a c t o r y metals 3 2 4 , 3 3 7 451,454,464,472,481ff,502f,514f ,528, r e l a t i v e l i n e i n t e n s i t y , s e e emission 539,542,545,551,554,567,581f probability s e l f - a b s o r p t i o n , see matrix absorption - reaction yield, see yield, semiconductor detector, see detector, activation semiconductor resolution, see detector resolution - material 372,580 resonance energy 21ff sensitivity 7 , l l , 3 0 5 , 3 3 3 f f , 3 5 6 f , 3 6 0 , r e s o n a n t c a v i t y , see c a v i t y , r e s o n a n t 370f,386f,388,399,401,404,412,455ff, rf-system 62ff,67 493 -generator 62ff serum 4 8 3 f , 4 9 7 f rhenium 1 9 0 f , 2 0 8 , 3 1 0 , 6 0 4 s e w a g e s l u d g e 480 ( s e e a l s o w a t e r rhodium 1 8 0 , 1 9 8 , 3 0 8 , 4 0 1 , 4 5 1 , 5 2 7 f , 5 5 8 f , related material) 587f short-lived nuclides 4 0 1 , 4 0 8 , 4 1 1 , 4 1 4 , rock material 3 9 4 , 4 7 4 , 5 0 5 f f , 5 4 8 f f 445,452ff,598,600 r o t a t i n g sample position 1 6 2 , 4 0 8 , 4 1 2 , S i ( L i ) - d e t e c t o r , see d e t e c t o r , Si(Li) 467,473,484,508f s i g n a l summation 116f R o u n d - R o b i n a n a l y s i s , see i n t e r signal-to-Compton ratio 1 2 9 f f , 1 5 7 , 1 3 4 , l a b o r a t o r y comparison analysis 334,403,414,423,507

704 silica 3 3 8 f , 3 4 4 f f , 4 6 2 silicon 1 7 1 , 3 0 6 , 3 2 3 f , 3 3 7 , 3 4 4 , 3 6 3 f , 376,383,389,392,401,454,464,472,481f, 515,539,542,545,551,570 silver 1 8 1 , 1 9 8 , 3 0 8 , 3 2 3 , 3 4 7 , 3 4 9 , 3 8 0 , 397,451,454,472,481f,502,514f,527f, 539,542,545,554,558f,561,567,588f single c h a n n e l a n a l y s e r ( S C A ) , see pulse-height analyser - comparator 407f sodium 1 7 1 , 3 0 6 , 3 2 4 , 3 4 3 , 3 5 9 , 3 6 3 , 3 7 2 , 3 7 6 , 385,389,392,397,402,464,472,481f, 485,501ff,514f,527f,539,542,545, 495ff,554,563ff,567ff soil material 4 6 0 f , 4 6 5 f f , 4 7 4 , 4 9 3 f , 4 9 6 s o u r c e geometry 1 2 7 , 1 5 8 , 3 2 8 f spectrometer 93ff - l i n e a r i t y , see d e t e c t o r l i n e a r i t y spectrometry range 130f,135 s p e c t r o s c o p y amplifier 9 4 , 1 4 0 f f , 1 5 7 s p e c t r u m s t a b i l i s e r 155 s p h e r i c a l nuclei 22 s t a n d a r d r e f e r e n c e material, see r e f e r e n c e material s t a n d a r d , see r e f e r e n c e material s t a t i c a c c e l e r a t o r , see a c c e l e r a t o r , static steel 3 2 3 , 3 3 7 , 5 7 6 , 5 7 8 , 5 8 6 strontium 1 7 7 f , 1 9 7 , 3 0 7 , 4 0 6 f , 4 3 8 f , 4 5 1 , 464,472,481f,486,501ff,514f,527f, 539,542,545,549ff,554f,563,565,567, sulfur 162,316,339,373f,454,571 s u r f a c e contamination 3 2 1 f f , 3 3 4 , 3 7 1 , 388,410,535 - t r e a t m e n t , see s u r f a c e c o n t a m i n . s u s p e n d e d m a t t e r , see w a t e r - r e l a t e d material s y n c h r o c y c l o t r o n 73 s y n c h r o m i c r o t r o n 73 synchrotron 73f,521

thorium 1 6 2 , 3 9 4 , 4 8 1 , 5 5 2 , 6 1 2 f threshold energy 1 5 f f , 3 1 7 , 3 3 2 , 3 3 6 , 3 5 2 f , 358,367f,384,388,397,399,412,42Of, 424,451,467f thulium 1 8 8 , 2 0 5 f , 3 0 9 , 5 2 7 , 6 0 1 thyroid 485f,497f time resolution 120f tin 1 8 2 f , 1 9 9 , 3 0 8 , 3 2 3 , 3 4 5 , 3 6 6 , 3 7 7 , 3 8 0 f , 401,440f,451f,454,464,472,481f,501ff, 514,536f,539,542,545,547,549,554, 561,563,567,59 If t i s s u e , see biological material titanium 1 7 2 f , 3 0 6 , 3 2 3 , 3 4 4 , 3 6 0 , 3 6 4 , 3 6 6 , 376f,396,433f,464,472,481f,501f, 514f,527f,539,542,545,549ff,554f, 567,573f tobacco 484,492 tooth samples 3 8 9 , 4 8 3 f total r e f l e c t i o n X - r a y f l u o r e s c e n c e 462 toxicity 362,480f tracer 355f,369,411 t r a n s u r a n i u m elements 5 4 , 6 1 2 f t r a v e l l i n g wave 64 t r e e b a r k 484 tungsten 190,207f,310,350,366,381,389, 445,451,453f,481,514f,521,527,501, 603f u l t r a s o n i c bath 3 2 2 , 3 2 4 uranium 5 3 f , 1 9 3 , 2 1 2 , 3 1 0 , 3 9 4 , 4 5 3 , 4 6 4 , 472,475,481f,502,528,539,543,546,549. 552,563,567,612f urine 3 9 4 , 4 8 3 f f vacuum f u s i o n , see f u s i o n , vacuum vanadium 1 7 3 , 1 9 5 , 3 0 6 , 3 3 7 , 3 4 5 , 3 7 7 , 4 3 3 f f , 464,472,482,502,542,554,567,574f Van de G r a a f f g e n e r a t o r , see accelerator, static vapour distillation 3 8 8 f f , 3 9 8 f v e c t o r gas 3 3 7 f f , 3 4 3 f f , 3 6 3 f f , 3 7 3 , 3 7 6 f f volatility loss 3 3 7 , 3 9 0 , 4 0 3 , 4 1 1 f , 4 2 2 , 457,467,469f,487,494f,499f,582f,594, 605,608f,611

tantalum 1 9 0 , 2 0 7 , 3 1 0 , 3 5 0 , 3 6 5 , 3 8 1 , 514f,522,527,603 t a r g e t , see b r e m s s t r a h l u n g c o n v e r t e r - nuclide 6 , 5 1 , 2 1 3 waiting p e r i o d , see decay period technetium 162 w a t e r - r e l a t e d material 3 9 4 , 4 1 1 f f , 4 5 5 , tellurium 183f , 1 9 9 f , 3 0 8 , 3 4 7 , 4 0 1 , 4 5 1 , 477ff,488,510ff,552ff 472,474,481f,502,539,542,567,593 waveguide 64ff terbium 1 8 7 , 2 0 3 , 3 0 9 , 6 0 0 thallium 1 9 3 , 2 1 1 , 3 1 0 , 4 0 1 , 4 5 4 , 4 6 4 , 4 7 2 , w e l l - t y p e d e t e c t o r , see d e t e c t o r , 474,481f,486,502,514f,527,539,542, well-type 546,549f,552,555,563,565,567,609f whisky 4 8 4 , 5 3 7 thermal n e u t r o n s , see n e u t r o n s , thermal

705

Wilkinson-type analog-to-digital c o n v e r t e r , see a n a l o g - t o - d i g i t a l converter(ADC) window a m p l i f i e r , see d i s c r i m i n a t o r , differential window, see beam w i n d o w j d e t e c t o r entrance window;discriminator, differential

y i e l d , activation 1 3 f f , 4 6 f f , 1 6 2 f , 1 6 6 , 334,354,369,384,397,448ff - , chemical 3 3 5 , 3 5 4 , 3 6 0 , 3 6 9 f , 3 7 6 f f , 382,386,392ff,399 ytterbium 1 8 9 , 2 0 6 , 3 0 9 , 4 5 1 , 5 4 5 , 6 0 1 f yttrium 1 7 8 , 1 9 7 , 3 0 8 , 4 0 1 , 4 0 6 f , 4 3 8 f f , 451,454,464,472,481f,514f,527f,539, 542,545,549f,584f

X-ray fluorescence 111,115,403,409, 4 5 9 , 4 6 2 , 5 1 8 , 5 2 4 , 5 3 5 ( s e e also low e n e r g y photon s p e c t r o s c o p y ) X - r a y s p e c t r o s c o p y , see low e n e r g y photon s p e c t r o s c o p y X - r a y s , b r e m s s t r a h l u n g , see bremsstrahlung - , c h a r a c t e r i s t i c , see low e n e r g y photon s p e c t r o s c o p y

zinc 1 7 5 , 1 9 5 f , 3 0 7 , 3 2 3 , 3 4 7 , 3 9 6 , 4 5 4 , 4 6 4 , 466,472,475,481f,501ff,514,527f, 539,542,545,547,549,551f,554,561, 563ff,567,579f zircon 3 3 8 , 3 4 5 f zirconium 1 7 8 , 1 9 7 , 3 0 8 , 3 2 4 , 3 4 8 , 3 6 1 , 3 6 5 , 379,393,401,438ff, 451,454,464,472, 481f,486,501ff,505,514f,525,527f, 539,542,545,549ff,554f,563,565,657, 585f

Concise Nuclear Isobar Charts Nuclear Ground States and Low Lying Energy Levels Edited by Hans Bucha 1986. 5 charts printed in three colours, size 43 cm χ 100 cm, folded to fit into portfolio size 32 cm χ 44 cm; included is 24 page instruction / introduction manual. ISBN 311008404 X Summary In the course of the investigation of the atomic nucleus a considerable body of knowledge of properties of the nuclear energy levels associated with the different bound nucleon configurations has been accumulated to date. As a consequence of interactions of the nucleons in the atomic nucleus among themselves as well as with the electromagnetic field and the fields of weak interactions, many radiation processes occur in nuclear reactions and spontaneous decays in which the initial nucleon configuration is changed into other ones. The transition probabilities for these processes essentially depend on the properties of the nuclear energy levels as well as on the interactions involved. In the concise isobar charts, data on binding energies of protons and neutrons in the ground state and excitation energies for low-lying nuclear energy levels, both of which are of great interest for transition processes as well as questions of nuclear structure, are displayed. Also, quantum numbers for angular momentum and parity are shown for these energy levels. For the stable nuclei, data for the relative abundances, and for unstable nucleon configurations, the transition probabilities are included in the data displayed. Information on branching ratios, e. g., for ß-decay, electron capture, γ-ray transitions, or internal conversion processes are also included. The isobar nuclei, characterized by the same atomic number A, which is the sum of proton number Ζ and neutron number N, are written in one row according to increasing values of h = (Z - N)/2. The isobars are arranged in the vertical direction. Due to the representation chosen for the atomic nuclei, in many cases a very clear first survey of systematic properties of nuclear energy states as well as spontaneous decay processes is achieved.

w WALTER DE GRUYTER · BERLIN · NEW YORK DE

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Verlag Walter d e G r u y t e r & Co., G e n t h i n e r Str. 13, D-1000 Berlin 30, Tel.: (0 30) 2 60 05-0, Telex 1 84 027 Walter de G r u y t e r Inc., 200 Saw Mill River R o a d , H a w t h o r n e , Ν. Y. 10532, Tel.: (914) 747-0110, Telex 64 6677