On the Radioactivity of K40

Citation preview

0* THto EADIOACTIVITY OF

FORDHAM UNIVERSITY GRADUATE SCHOOL

May 15

^50

This dissertation prepared under my direction by

Paul Kramer entitled ....................... ON THE SAD10ACT17 ITT OF jrf?.....................

has been accepted in partial fulfilment of the requirements for the Degree of

Doctor o f Philosophy

Dr« Vic t o r Bess.............. (Faculty Adviser)

ON THE BABIOA CTIV IT Y OF K40

BY PAUL ERAMEB A . B . , B r o o k l y n C o l l a g e , *45 M . S . , F o ra h am U n i v e r s i t y , *46

DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN THE DEPARTMENT OF PHYSICS AT FORDHAM UNIVERSITY

NEW YORK 19&0

ProQuest Number: 10993022

All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is d e p e n d e n t upon the quality of the copy subm itted. In the unlikely e v e n t that the a u thor did not send a c o m p le te m anuscript and there are missing pages, these will be noted. Also, if m aterial had to be rem oved, a n o te will ind ica te the deletion.

uest ProQuest 10993022 Published by ProQuest LLC(2018). C opyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States C o d e M icroform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346

r

iii n

r

TABLE OF CONTENTS Page LIST OF T A B L E S ...........................................

..

LIST OF FIGURES...............................................................................

iv V

iiGEMOWLEDGMEBTS.......................................................... I. II. III.

INTRODUCTION.............................. ............. ............. .. FEATHER ANALYSIS.

.........................

Vi 1 6

OWN EXPERIMENTS ON THE BETA RAYS FROM POTASSIUM................

15

OWN EXPERIMENTS ON THE GAMMA RAYS OF POTASSIUM..............................................................................

23

STUDY OF THE ABSORPTION OF GAMMA RAYS IN POTASSIUM SALTS................. ................................. ..

34

EXPERIMENT ON THE RADIUM EQUIVALENT OF ..................... R a -h B e SOURCES..

38

V II.

SUMMARY.......................

45

V III.

APPENDIX..................

47

IV . V. V I.

52

BIBLIOGRAPHY...............................................................

L

-I

iv

r

“i

LIST OF TABLES

T ab le I.

IX . III. IV .

Bag© R adium e q u i v a l e n t o f 1 gram o f p o t a s s i u m , a n d m ass a b s o r p t i o n c o e f f i c i e n t o f t h e gaum a r a y s f ro m p o t a s s ium .................

£

Maximum e n e r g y o f t b e gamma r a y s fr o m p o t a s s ium . * . .....................

4

B | g i n t e g r a t i o n c o n s 'c a n t and b a l f l i f e

of

A p p a r e n t r a d i u m e q u i v a l e n t o f a R a + B© ............................... so u rce

43

V 1

r

LIST OF FIGURES fig u re 1.

D ire c t ra n g e d e te r m in a tio n f o r b e ta p a r t i c l e s .............................................

.......

9

S.

P r e p a r a t i o n o f f e a t h e r a n a l y s e r . . ..........................

11

S.

f e a t h e r a n a ly s is o f an a b s o rp tio n c u rv e

11

4.

D e t e r m i n a t i o n o f r a n g e fro m f e a t h e r p l o t . . . .

IE

5.

Range and e n e r g y o f e l e c t r o n s and n u c l e a r b e t a p a r t i c l e s ..................................................

IS

B l o c k d ia g ra m o f g e i g e r t u b e , h i g h p o t e n t i a l s o u r c e , a m p l i f i e r , a n d r e c o r d e r . . . ......................

16

A.

C o u n tin g r a t e v s t h i c k n e s s o f K C l . . . . . . . . . . .

19

B.

Log o f c o u n t i n g r a t e v s t h i c k n e s s o f alum inum f o r K C l ...........

El

Log o f c o u n t i n g r a t e v s t h i c k n e s s o f alum inum f o r RaD + E . ................................

EE

C i r c u i t d i a g r a m o f L indem ann e l e c t r o m e t e r w i t h a c c o m p a n y in g v o l t m e t e r , b a t t e r i e s , and sw itc h e s ...............................

£3

C y l i n d r i c a l c a r t o n s o f EgSO^ s u r r o u n d i n g i o n i z a t i o n c h a m b e r ..............

E7

G r a p h i c a l i n t e g r a t i o n m e th o d .....................................

£9

RaO s o u r c e e n c l o s e d i n i r o n h o u s e w i t h p o t a s s i u m s a l t s a s a b s o r b e r ...............................

36

Log o f i o n i z a t i o n v s t h i c k n e s s o f i r o n , f o r R a , and R a 4 - B e . . . . • ............

41

11.

C i r c u i t d iag ra m o f h ig h v o l ta g e s u p p ly

60

1£.

C i r c u i t d i a g r a m o f a m p l i f i e r .........................

51

6.

0. 7.

6. 9. 10. B.

L

Page

tfes anther w ish es i s ex p ress h is g r a titu d e ? , I . l e s s f ar h is in s p ir a t io n a l guidance *

JH

r I.

Ifl'J&GDUCTIOff

I h e r e art? o n l y f o u r r e l a t i v e l y l i g h t e l e m e n t s t h a t a re n a t u r a l l y r a d i o a c t i v e : p o ta ssiu m , ru b id iu m , lu te c iu m and sa m a riu m .

The a c t i v i t y

i n r u b i d i u m and p o t a s s i u m was

fo u n d i n 1906 by S . ,e

l l known u p t o 1 9 4 6 ;

e x i s t i n g d a t a w e re m ea g er and c o n f l i c t i n g .

By m ea n s o f

a b s o r p t i o n m e a s u r e m e n ts , v a r i o u s a u t h o r s d e t e r m i n e d t h e i n t e n s i t y o f t h e gamma r a y s fro m p o t a s s i u m i n t e r m s o f e q u i v a l e n t a m o u n ts o f h g C , g i v e n i n f a b l e 1 t o g e t h e r w i t h t h e c a l c u l a t e d m ass a b s o r p t i o n c o e f f i c i e n t s , c le a rly

illu stra te s

i 'a b l e 1

th e d i f f e r e n c e s i n t h e v a l u e s o b t a i n e d .

2 r S a b le

1

1 -g p o tassiu m e q u iv a le n t to :

Mass a b s o r p t i o n c o e ffic ie n t of gamma-rsy s fr o m p o tassiu m

W. K o l h o r s t e r 2^

5.1QXlO-i:ig Ba

G.025G e m ^ /g

W. M iih lh o ff^ 4

5 . M * 1 0 ~ 1;ig Ba

0 . 0 3 2 0 om2 / g

P . B ehou nek^

1 .3 0 X 1 0 - 10g Ba

0 . 0 5 1 3 e m ^ /g

I». H. G ra y and G. S . P . T a r r a n t ^

l.b O X lO -^ ^ g Ba

G.G4?? amz / g

B . G l e d i t s o h and S. G r a f t s

1 .2 3 X lo -i 0 g h a

0 . 0 5 1 3 cm2 / g

A u th o r

G i e a i t s e h and G r a f 1s ^ ^ r e o e n t d e t e r m i n a f i o n o f t h e i n t e n s i t y o f t n e gamma r a y s fro m p o t a s s i u m seem s t o i n d i c a t e m e e s s e n t i a l c o r r e c t n e s s o f B e h o u n e k 1s s v a l u e .

P re v io u sly

i t had b e e n t h o u g h t t h a t G ra y and T a r r a n t * v a l u e was t h e ^ 21 m ost r e l i a b l e and B e h o u n e k 's th e l e a s t . B ess in h is i n v e s t i g a t i o n o f t h e gamma r a y s fro m g r a n i t e , fo u n d a g r e a t e r gamma r a y i n t e n s i t y t h a n c o u ld

be e x p l a i n e d by t h e

known c o n t e n t o f u r a n i u m , t h o r i u m and p o t a s s i u m .

H ess had

u se d t h e a c c e p t e d v a lu e o f G ra y and T a r r a n t f o r th e c o m p u t a t i o n o f th e gamma r a y i n t e n s i t y , w h ic h was c o n s i d e r ­ a b l y l o w e r t h a n t h a t o f G l e d i t s o h and G r a f , r a d i a t i o n fro m g r a n i t e c o u ld be a s c r i b e d

T h is s u r p l u s

to p o ta s s iu m i f

G l e d i t s o h and G r a f * s v a l u e p r o v e d t o be c o r r e c t . S i n c e t h e e x i s t i n g d a t a on t h e gamma ana b e t a r a y s fro m p o t a s s i u m w ere so m eag er and c o n f l i c t i n g , i s e e

sa b le

3

r 2 and 3 ) , i t was d e c i d e d

th a t a th o ro u g h s tu d y o f th e

r a d i a t i o n s f ro m p o t a s s i u m would be of

i m p o r t a n c e and o f

in te re s t. I n 1947 t h e a u t h o r u n d e r t h e supe r v i s i o n o f ■Or. V. Jf. H e s s u n d e r t o o k s u c h a s t u d y .

S u b se q u e n tly i n

CO

i y 4 8 , H ess a n d H o l l

i n t h e i r i n v e s t i g a t i o n o f t h e gamma

r a d i a t i o n f r o m XCi and £gSC>4 , fo u n d t h a t th e m ass a b s o r p ­ tio n c o e f f ic ie n t, n /f

f was 0 .0 5 2 3 om ^/g and t h a t one gram

o f p o t a s s i u m w as e q u i v a l e n t t o

0 . 89x 10-10

g ram s o f r a d i u m ,

f h e s e v a l u e s c o r r o b o r a t e d t h o s e r e p o r t e d by G l e d i t s o h and G raf. An e x a c t e v a l u a t i o n o f th e u p p e r e n e r g y l i m i t o f t h e c o n tin u o u s b e t a r a y s p e c tru m o f p o ta s s iu m , i s fu n d a m e n ta l f o r t h e b e t a r a n g e d e t e r m i n a t i o n and f o r c o m p a r i s o n s w i t h o th e r b e ta e m itte r s ,

fh e v a lu e s o f th e upper energy l i m i t

f o r t h e b e t a r a y s fro m p o t a s s i u m , a s o b t a i n e d by v a r i o u s a u t h o r s , a r e show n i n t a b l e 2 .

4 n

r S ab le 2 A u th o r

Maximum E n e rg y o f r a y s fro m K

M ethod

B. B zelepow lO

0 . 7 - 1 . 3 Mev

Mass Spe e t r o m e t e r

S. E r a n c h e t t i & M. G i o v a n o z s i * ^

1 . 7 0 M©v

Oloud Chamber

0- H i r z e l & H. W a f f i e r ^

1 . 4 1 Mev

A b s o r p t i o n throug h m e ta ls { le a th e r A n a ly sis)

L. B. B o r s t ,& J. J . F l o y d 4"

1 . 9 0 Mev

L . B. B o r s t & J . J . Floyd® ( c o r r e c te d v a lu e )

1 . 4 5 Mev

W, J . He net e r s o n ^

1 . 3 0 Mev

B. E . A i b u r g e r 2

1 . 4 0 Mev

Mass S p e c t r o m e t e r

W. 1 , L ib b y & D. 3). L ee$ 2

0 .7 2 5 Mev

f e a th e r A n a ly sis

S. H. H edderm yer 8 0 . I). And e r so

0 . 7 0 Mev

Cloud Chamber

fhe r a d i o a c t i v e

t r a n s f o r m a t i o n o f x 9 ^ ^ o a n be

a c c o m p l i s h e d by two d i s t i n c t p r o c e s s e s , MK” e l e c t r o n c a p t u r e , and b e t a p a r t i c l e e m i s s i o n . ’i 'he d e c a y o f i s e x p r e s s e d a s : i 9^ 4 ° +

i n t o ^^A40 b y "Kn e l e c t r o n c a p t u r e ©'

i 8a 40 +

fa V

1 5 ,2 7 , w h e re h v = l , 5 Mev~

H. A. M y e r ^ , showed t h a t t h e gamma r a d i a t i o n was a s s o c i a t e d o n l y w i t h t h e "Kn e l e c t r o n c a p t u r e p r o c e s s , a s i n a s e r i e s o f P Y c o i n c i d e n c e e x p e r i m e n t s , no s u c h c o i n c i d e n c e s w ere re c o rd e d Be showed t o o , t h a t t h e d e c a y o f i * * 40 i « °

a r g o n was due t o

5 e l e c t r o n c a p t u r e , s i n c e he c o u ld n o t d e t e c t a n y p o sitro n a c tiv ity . i'ne r a d i o a c t i v e t r a n s f o r m a t i o n cf

p o tassiu m in to

c a l c i u m by b e t a p a r t i c l e e m i s s i o n i s e x p r e s s e d a s : ly

*40

(,_40 W S i n c e t h e gamma r a d i a t i o n was f ouid t o

be a s s o c i a t e d

w i t h t h e MKM e l e c t r o n c a p t u r e p r o c e s s , i t i 8 , t h e r e f o r e , m o s t l i k e l y t h a t t h e gamma r a d i a t i o n i s e m i t t e d by a to m s l e f t i n a n e x c i t e d s t a t e ,

t h e r e f o r e th e d i s i n t e g r a ­

t i o n schem e a s g i v e n by 0 . H i r z e l & H. waf f l e r 2 6 ;

and

B. Cried i t sc h & T . G r a f 1 ^ , se ems e s s e n t i a l l y c o r r e c t f n a m e ly : 40 K 19

h v = 1 . 5 Mev

15 I1o r © very 100 b e t a p a r t i c l e s e m i t t e d

th e r e a re ? to

5 . Y gamma q u a n t a e m i t t e d 'i'he t r a n s f o r m a t i o n c o n s t a n t X f o r p o t a s s i u m i s e q u a l t o t h e sum o f t h e d e c a y c o n s t a n t s A + X e , w here A p i a p r o p o r t i o n a l t o t h e num ber o f a to m s d e c a y i n g p e r se c o n d b y e m i t t i n g b e t a L

-J

p a r t i c l e s , a n d A e i© p r o p o r t i o n a l t o t h e num ber o f a to m s d e c a y i n g toy It e l e c t r o n c e p t n r e . * eo o rd in g to 1. O r i f ! * ^

= 1 * 6 or f o r a g iv e n tim e

i n t e r v a l 1 . 6 t i m e s more a r g o n t h a n c a l c i u m s h o u l d toe fo rm ed am a r e s u l t o f

decay.

I n t h e l i t e r a t u r e c o n f l i c t i n g v a l u e s o f A orih the r e f o r m of f the h a lf l i f e

of

Cw h i c h i s r e l a t e d i o A b y 3P 0 . 6 0 3 ) A a r e r e p o r t e d , f a r e ta to i# 3 ) S&ble t M vth o r__________

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6.0 X 1 0 *

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c o r r e c t ve l a s f o r f i s p r o b a b l y 4 - 6 x 10* y e a r s , a s

determ ined toy £lbarger*% Ahrens As Evans1 * 1 Sled i t s oh & 2 r a t 16*

f h e o t h e r a u t h o r s had n e g l e c t e d th-

te a tte riri^ .

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a rr iv e* a t th e ir va lu e fo r 1 the h a lf l i f e o f potassium by means o f th e r a t io o f Qa*0/ o f the rnioa fa m ily ,

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i n i s n o v el method served a s an

e x c e lle n t ahsefc f o r sh e more customary p rocedu res.

L

6 *1

r I I . FEATHER ANALYSIS

By u s e o f v e r y s i m p l e m e t h o d s ana e q u ip m e n t ; , i t possible

is

to d e te r m in e th e e n e r g i e s o f b e ta r a d i a t i o n s .

T h es e met no d s r e l y u p o n t h e f a c t t h a t b e ta

p a r t i d e s axe

n i g h s p e e d e l e c t r o n s and t r a v e l o n l y t h r o q g h r e l a t i v e l y s h o r t d i s t a n c e s in to an a b so rb in g m a t e r i a l . Tne t h i c k n e s s o f a b s o r b e r p e n e t r a t e d

is d i r e c t l y

p r o p o r t i o n a l to the i n i t i a l en erg y o f the b e ta p a r t i c l e , and i n v e r s e l y p r o p o r t i o n a l t o t h e s q u a r e o f t h e a t o m i c number 2 o f t h e a b s o r b e r ^ . T h e re fo re tne b e ta p a r t i c l e

in i t s

tran sit

through a

g r o u p o f a to m s s u f f e r s a d e f l e c t i o n due p r i m a r i l y t o i t s ins e n a c tio n w ith the n u c l e i of the a b s o r b e r .

The t h i c k n e s s

of a b so rb e r t h a t w i l l s to p the beta p a r t i c l e s c o m p le te ly is rj

c a l l e d t h e r a n g e , and i s u s u a l l y e x p r e s s e d i n g/cm*- , l a u n i t w hich i s in d ep e n d en t of th e type o f a b s o rb in g m a t e r i a l ) The r a n g e o f a b e t a p a r t i c l e by t h e d i r e c t m e t h o d . abssrrbers in te rp o se d

i s v e ry sim p ly d e te rm iie d

A c tiv ity rea d in g s are taken w ith m etal b e tw e e n t h e c o u n t e r and t h e s o u r c e ,

t e e n t h e l o g a r i t h m o f t h e c o u n t i n g r a t e 1c o r r e c t e d f o r b a c k ­ g ro u n d ) iB p l o t t e d a g a i n s t t h e a b s o r b e r t h i c k n e s s ( t h e m e t a l , t h e t h i c k n e s s o f a i r g a p and t h e c o u n t e r w i n d o w ; , i t observed

is

t h a t t h e r e i s a t h i c k n e s s o f a b s o r b e r beyond w h i c h

no p a r t i c l e c a n p e n e t r a t e .

T his i s th e d i r e c t ra n g e .

f i g u r e 1 r e p r e s e n t s a t y p i c a l curve i n the d e te r m i n a ti o n o f t h e r a n g e o f a b e t a n a r t i c l e by t h i s m e t h o d . 10,000

1000 2 a u

>

100

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