ANL-5174 ARGONNE NATIONAL LABORATORY PHYSICS DIVISION/67531/metadc1022202/m2/1/high_r… ·...
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ANL-5174 -/- ARGONNE NATIONAL LABORATORY P. O. Box 299 Lemont, Illinois -?^Ux PHYSICS DIVISION QUARTERLY REPORT SEPTEMBER, OCTOBER, AND NOVEMBER, 1953 Louis A. Turner, Division Director February, 1954 Preceding Quarterly Reports: ANL-5140 June, July, and August, 1953 ANL-5141 June, July, and August, 1953 (Secret) ANL-5080 March, April, and May, 1953 ANL-5081 March, April, and May, 1953 (Secret) Operated by The University of Chicago under Contract W-31-109-eng-38
Transcript of ANL-5174 ARGONNE NATIONAL LABORATORY PHYSICS DIVISION/67531/metadc1022202/m2/1/high_r… ·...
ANL-5174
- / -
ARGONNE NATIONAL LABORATORY P . O. Box 299
L e m o n t , Illinois
-?^Ux
PHYSICS DIVISION
QUARTERLY REPORT
SEPTEMBER, OCTOBER, AND NOVEMBER, 1953
Louis A. T u r n e r , Division Director
F e b r u a r y , 1954
Preced ing Quar te r ly Repor t s :
ANL-5140 June , July, and August , 1953 ANL-5141 June , July, and August , 1953 (Secret) ANL-5080 March , Apr i l , and May, 1953 ANL-5081 March , Apr i l , and May, 1953 (Secret)
Operated by The Universi ty of Chicago under
Contract W-31-109-eng-38
DISCLAIMER
This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.
DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.
2
Titles given in pa ren theses a r e those of continuing p r o g r a m s ,
in which no p r o g r e s s has been m a d e , ei ther in work done or in publication
during the c u r r e n t qua r t e r .
TABLE OF CONTENTS
Page
I. EXPERIMENTAL NUCLEAR PHYSICS
1-4 (The Argonne F a s t Neutron Velocity Selector) Lowell M. Boll inger 11
2-4 Liquid Scintil lation Neutron Detector George E. T h o m a s , J r 11
3-4 Transnaiss ion Measurements with the Fas t Neutron Velocity Selector
Lowell M. Bollinger 15
5-3 (The Absorpt ion and Scat ter ing of Neutrons by Hafnium) . . 17
6-3 Spiral Velocity Selector for Slow Neutrons
Roy Ringo . . 17
11-4 Instal la t ion and Operat ion of the Van de Graaff Generator
1. Instabili ty of the Posi t ion of the Ion Beam F . Paul Mooring 17
2. The Corona System F . Paul Mooring 18
3. Inc rease of Voltage F . Paul Mooring 18
4. The 90° E lec t ros ta t i c Analyzer R. Ray Weeks . . . . . 18
5. Beam Cur ren t Integrator Alexander Langsdorf , J r 18
6. Operat ional Exper ience Jack R. Wallace , 19
3
3 TABLE OF CONTENTS CONTINUED
Page
12-4 (R. F . Ion Source for the Van de Graaff Generator) F . Paul Mooring 20
14-3 Pulsed Neutron Beams Robert E. Holland 20
20-4 Energy States of Light Nuclei from Charged Pa r t i c l e Reactions
Robert E. Malm 21
3 0-4 Scintillation Coincidence Spec t rometer S. Bradley Burson 22
31-4 (The 1.42 Min I somer ic State in -jjlr^^^) S. Bradley Burson 22
32-4 Decay Scheme of ^^Dy^^^"^ (1.2 min) and ^^^^Dy^^^ (2. 3 hr)
Willard C. Jordan 22
35-4 Decay Schemes of Long-Lived R a r e - E a r t h Isotopes Eugene L. Church 23
36-4 The Decay Schemes of Mass 48 Nuclei Harvey Casson 24
38-2 The Radiations from £,5Tb^^^ S. Bradley Burson 25
52 40-2 The Decay Scheme of 23V
J a m e s M. LeBlanc 28
41-2 The Decay Schemes of 48Cd and 4gln J a m e s M. LeBlanc 29
43-1 The Decay of the 3. 5-min Metastable State of Sb^ ^ J ames M. LeBlanc 29
45-1 The Shor t -Lived Activit ies of Zn J a m e s M. LeBlanc 32
TABLE OF CONTENTS CONTINUED
Page
46-1 The Decay of 32Ge^^ (12 hr) and 3306^^"^ (59 sec) S. Bradley Burson 35
50-4 (Internal Convers ion of Capture Gamnna-Rays Associa ted with Gd)
C a r l T. Hibdon 36
51-4 C h a r a c t e r i s t i c s of a Scintillation Counter Spec t rometer Arthur L. Recks iedler 36
52-4 Neutron Capture Gamnna-Ray Studies with the Scintillation Spec t rometer
Ar thur L. Recks ied ler 36
60-4 Eight -Meter Bent C rys t a l Spect rometer B e r n a r d H a m e r m e s h 37
70-4 Measurements of Nuclear Moments by Angular Corre la t ion Sol Raboy 37
71-4 The Angular Cor re la t ion of p-Rays and Delayed Neutrons from B r ° '
Leonard S. Goodman 39
80-4 Molecular Beam Studies Leonard S. Goodman 39
90-4 Cros s Sections for 14-Mev Neutrons Harvey Casson 42
91-4 Neutron T r a n s p o r t C ros s Sections Alexander Langsdorf , J r 42
92-4 (Neutron Scat ter ing C r o s s Sections by Use of the Scat ter ing Chamber)
C a r l T. Hibdon 42
TABLE OF CONTENTS CONTINUED
Page
96-4 (Pile Absorpt ion Cross Sections) David Rose 43
98-3 Total Neutron Cros s Sections in the kev Region Alexander Langsdorf , J r 43
98-3 Total Neutron Cros s Sections in the kev Region Car l T. Hibdon 43
99-2 Standards for Measuremen t of Thermal Neutron Absorption C r o s s Sections
Roy Ringo 48
100-1 The C r o s s Section of the L i " (n,a) T Reaction F . Paul Mooring 49
101-1 A Proposed Method for Measuring Radiative Capture Cross Sections
F . Paul Mooring 50
102-1 Self Detection of Neutron Cros s Sections William A. Reardon 51
109-3 Neutron Diffraction Apparatus Roy Ringo 52
110-3 (Crysta l Spec t rometer for 0. 1 to 100-ev Neutrons) Sol Raboy 52
112-4 (The Neutron Spec t rum of a Standard Ra-Be Photo Source)
Char les Eggler 52
114-2 Development of a Recoil Type Neutron Spec t rometer Gilbert J. Pe r low 53
115-2 Neutron Counters Containing Boron Tr imethy l Alexander Langsdorf , J r . 53
6
L TABLE OF CONTENTS CONTINUED
Pag e
120-4 Cal ibra t ion of a Ra-Be Neutron Source Willard C. Jordan 54
131-4 Average Charge of Daughter Atoms After Nuclear Exci ta t ion
Sol Wexler 55
132-4 (Chemical Service Work) Sol Wexler 55
133-3 Design Study of a Multi-Bev Proton Synchroton John J. Livingood 55
3 134-3 Optical Exci tat ion Spectra of He"̂ Species After (3"
Decay of T2 Sol Wexler 55
135-3 E lec t ron-Neut ron Interact ion
Roy Ringo 57
II. MASS SPECTROSCOPY
1-4 Mass Spec t rometr ic Techniques David C. Hess 59
2-4 Construct ion of MA-17 Henry E. Stanton 59
10-4 A Search for Rare Natural ly Occurr ing Isotopes David C. Hess 60
11-4 Technetium in Nature Mark G. Inghram 60
12-4 (Double Beta Dis in tegra t ion of Tel^O) Richard J. Hayden 60
30-4 The Heat of Vaporizat ion of Carbon Mark G. Inghram 61
7
7 TABLE OF CONTENTS CONTINUED
Page
31-4 (Studies of E l e c t r o n Impac t ) W i l l i a m A. C hupka 6 l
3 3 - 4 ( M o l e c u l a r S t a t e s in R a r e G a s e s ) Dav id C. H e s s 61
34 -4 A r g o n Age D e t e r m i n a t i o n s R i c h a r d J. H a y d e n 61
III. C R Y S T A L L O G R A P H Y
1-4 ( C r y s t a l S tud ies of T e c h n e t i u m C o m p o u n d s ) W i l l i a m H. Z a c h a r i a s e n 63
2 -4 ( S t r u c t u r a l S tud ie s of B o r i c Ac ids ) H. Anne P l e t t i n g e r 63
2 0 - 2 (Tab le of S q u a r e d S ines) H. Anne P l e t t i n g e r . 63
IV. E X P E R I M E N T A L R E A C T O R PHYSICS ( C o v e r e d in A N L - 5 1 7 5 , P r o g r a m C IV)
V. T H E O R E T I C A L P H Y S I C S , G E N E R A L
1-4 I n t e r p r e t a t i o n of the E n e r g y S t a t e s of L i g h t N u c l e i Dav id R. Ing l i s 64
2 -4 E n e r g y S t a t e s of L i g h t N u c l e i D i e t e r K u r a t h 64
4 - 4 ( I n v e s t i g a t i o n of N u c l e a r S t r u c t u r e ) M a r i a G. M a y e r . . . . . . . . 65
8
T A B L E O F C O N T E N T S CONTINUED
F k g e
5-4 (Book on N u c l e a r Shel l S t r u c t u r e ) M a r i a G. M a y e r 65
7-4 C o l l e c t i v e D e s c r i p t i o n of N u c l e o n I n t e r a c t i o n s M e l v i n F e r e n t z 66
8-4 M o n o e n e r g e t i c N e u t r o n s f r o m C h a r g e d P a r t i c l e R e a c t i o n s
W i l l i a m A. R e a r d o n 67
9 -2 N u c l e a r C r o s s S e c t i o n s by the Clouded C r y s t a l Ba l l F o r m a l i s m
B e r n a r d I. S p i n r a d 67
2 8 - 3 A n g u l a r D i s t r i b u t i o n of E l a s t i c a l l y S c a t t e r e d N e u t r o n s M o r t o n H a m e r m e s h 68
2 9 - 3 I n t e r n a l C o n v e r s i o n in the L and M Sub-She l l s E u g e n e L . C h u r c h 68
3 0 - 4 ( C o n s u l t a t i o n on M i s c e l l a n e o u s T h e o r e t i c a l P r o b l e m s ) M o r t o n H a m e r m e s h 73
3 1 - 4 (Conf igu ra t i on I n t e r a c t i o n in I r o n G r o u p E l e m e n t s ) N o r b e r t R o s e n z w e i g 73
3 2 - 4 P l u r a l S c a t t e r i n g of E l e c t r o n s at Obl ique Inc idence J a m e s E . M o n a h a n 73
3 4 - 4 Q u a n t i z e d Space T i m e K a t s u m i T a n a k a 73
3 7 - 3 On the R e l a t i o n of the S c h r o d i n g e r and B o l t z m a n E q u a t i o n
Katsunni T a n a k a 74
38 -2 C e r e n k o v R a d i a t i o n K a t s u m i T a n a k a 74
I TABLE OF CONTENTS CONTINUED
Page
39-2 Applications of the Theory of Angular Cor re la t ion Norber t Rosenzweig 75
40-2 Compton Scat ter ing Katsumi Tanaka 76
41-1 Solutions of the Dirac Equation for a F r e e Pa r t i c l e Katsumi Tanaka 76
VI. REACTOR THEORY
7-1 Lec tu re s on Neutron T r a n s p o r t Theory B e r n a r d I. Spinrad 79
VII. E L E C T R O N I C DIGITAL C O M P U T E R S
0-2 R e p o r t on the D i g i t a l C o m p u t e r S y m p o s i u m J . C . Chu gQ
1-4 ( R e p o r t on the D e s i g n of the AVIDAC) R a y m o n d F . K r a m e r QQ
2 - 4 I m p r o v e m e n t s of the AVIDAC C a r l J. B e r g s t r o m . gQ
3-4 O p e r a t i o n and M a i n t e n a n c e of the AVIDAC Dav id H. J a c o b s o h n g2
4 - 4 ( T e s t Rou t ines for the AVIDAC) J e a n F . Ha l l g2
5-4 S u b - R o u t i n e L i b r a r y for the AVIDAC J e a n F . Ha l l g3
6-4 (Coding M a n u a l for the AVIDAC) Dona ld A. F l a n d e r s g3
7-4 The A u x i l i a r y M e m o r y for the AVIDAC and O R A C L E L e s l i e C. M e r r i l l g3
10
TABLE OF CONTENTS CONTINUED
Rige
8-4 (A P r o b l e m in Par t i t ions) Donald A. F l ande r s 84
13-1 New Memory for the AVIDAC Raymond F . K r a m e r 84
20-3 Report on R e s e a r c h , Development, and Design of the ORACLE
J. C. Chu 85
21-4 Operation of the ORACLE Raymond F . Kramer 85
VIII. APPLIED MATHEMATICS AND COMPUTATION, GENERAL
1-4 IBM Methods and P rocedu re s N. F rank Morehouse 87
2-4 Report on Technical Details of General Purpose Boards N. F r a n k Morehouse 87
10-3 (Three-Group Calculat ion of Cr i t ica l Mass and Flux Plots)
Katsumi Tanaka 87
11-2 (Computations of the Absorption of p Rays in Air) . . . 87
12-2 Computation of T ra c e s of Gamma Matr ices Donald A. F l ande r s 88
11
/ /
I. EXPERIMENTAL NUCLEAR PHYSICS
1-4 (The Argonne F a s t Neutron Velocity Selector) (5211-01 , 5261-01)
Lowell M. Boll inger
There is nothing new to r e p o r t for the pas t q u a r t e r .
2-4 Liquid Scintil lation Neutron Detector (5211-01, 5261-01)
Lowell M. Boll inger and George E. T h o m a s , J r . Reported by George E. T h o m a s , J r
In o rde r to col lect at the photomult ipl ier the max imum quantity
of light emit ted by the sc in t i l l a to r , one mus t use the bes t possible ref lector
on the inside of the counter . A sys temat ic invest igat ion of the ref lect ivi t ies
of poss ib le m a t e r i a l s to be used as the surface coating of l a rge volume liquid
scint i l la t ion counters h a s , t h e r e f o r e , been under taken and completed. The
m e a s u r e m e n t s were made using the radia t ion produced by Co g a m m a - r a y s
in a liquid sc int i l la tor consis t ing of 4 g m s / 1 of 2 , 5 diphenyloxazole and 16
m g s / 1 of diphenylhexatr iene dissolved in toluene of high pur i ty .
F igure 1 i l l u s t r a t e s the equipment used. Both spaces A and B
a r e filled with the scint i l la t ing liquid. The surface of B is coated all over
with the m a t e r i a l to be tes ted except for the sma l l hole at the top. The whole
inner a s sembly of photomult ipl ier and regions A and B can be moved up and
down as a unit inside the lead shield so that the gannma-ray b e a m can pass
ei ther through A or through B. F r o m the dis t r ibut ion of pulse he igh t s , the
average value of the pulse height for each posi t ion is de t e rmined , and the
value of the r a t io (P . H. )„ / ( P . H. ) is found. F r o m this ra t io the reflect ivi ty - D A
12
LEAD ^ SHIELD
PHOTOMULTIPLIER TUBE
XI
;
CHAMBER A
CHAMBER
B
Co^SsAMMA
BEAM
ENTIRE COUNTING SYSTEM MAY BE RAISED FOR BEAM THROUGH C H A M B E R " B "
FIG. I SYSTEM FOR MEASURING POSSIBLE
COUNTER REFLECTORS
13
13 of the coating of reg ion B is ca lcula ted as follows.
Consider an enc losure having walls coated with m a t e r i a l of
reflectivity R but with uniformly dis t r ibuted t r a n s p a r e n t openings , the a r e a of
such openings being a f rac t ion , a , of the total a r e a . If a scint i l la t ion anywhere
inside the enc losure produces an amount of luminous energy E , an amount
E a will escape without ref lec t ion, and E Q (1-a) will be re f lec ted , leaving
energy E^ (1-a) R after ref lect ion. Of this l a t t e r amount E (1-a) R a will
e s c a p e , and so on. The total amount escaping will be r e p r e s e n t e d by an
infinite geomet r ica l s e r i e s which totals to E = a E Q ^ s imi l a r
1 - R (1-a)
a rgument applies for an enc losure with a sma l l hole in i t , l ike the B enc losure
of the a p p a r a t u s , although it is difficult to compute the p r e c i s e value of a in
t e r m s of the d iameter of the sma l l hole. In computing the r e s u l t s , a has been
taken to be the ra t io of the a r e a of the hole to the total a r e a of the surface of
the conta iner . This will not give ent i re ly c o r r e c t r e su l t s for the absolute
values of R, but will give a lmos t exactly c o r r e c t re la t ive values of (1-R) for
the different r e f l e c t o r s . It is further a s sumed that light escaping from the hole
in B will be detected with the same efficiency by the photomult ipl ier as the
light emit ted in A when the g a m m a - r a y beam pas sed through that region.
This a lso may not be s t r i c t ly a c c u r a t e , but e r r o r s a r i s ing from this assumpt ion
will not affect the re la t ive values of 1-R. The m e a s u r e d ra t io (P. H. )-QI{^- H . ) ^
is set equal to the at tenuation r a t io a / 1 - R (1 -a ) , and R is calcula ted for the
know^n value of a. The r e su l t s a r e shown in the following table .
14
T a b l e I
R e f l e c t i v i t y of C o u n t e r S u r f a c e Coa t ings
R e f l e c t o r M a t e r i a l F o r m ( P . H. ) g / ( P . H . )
A l u m i n u m L i n d e A
M
T i 0 2 T i 0 2 MgO MgO T i 0 2
( a l u m i n u m oxide)
foi l i n w a t e r g l a s s
p o w d e r (ou t s ide) in w a t e r g l a s s p o w d e r in z a p o n (ou ts ide) p o w d e r (ou ts ide) p o r c e l a i n
0. 072 0. 169
0 . 3 0 4 0. 140 0. 193 0. 196 0. 236 0. 193
0. 0132 0 .0132
0 .0104 0 .0132 0 .0104 0 .0104 0 .0104 0 .0132
0 . 8 2 7 0 . 9 3 4
0 . 9 7 6 0 . 9 1 8 0 . 9 5 6 0 . 9 5 7 0 . 9 6 6 0 . 9 4 4
Since the u s e of m e t a l c o n t a i n e r s of l a r g e v o l u m e i s c o n t e m
p l a t e d i n t h e f u t u r e , t h e p o r c e l a i n r e f l e c t o r m a d e of p o r c e l a i n c o n t a i n i n g T i 0 2
s e e m s to be a good c h o i c e . T h e C h i c a g o V i t r e o u s E n a m e l C o m p a n y h a s b e e n
v e r y c o o p e r a t i v e in c o a t i n g t h i s r e f l e c t o r s u r f a c e for c o u n t e r s .
T e s t s show p u r e t o l u e n e to be a s s a t i s f a c t o r y a s p h e n y l c y c l o h e x a n e
a s the s o l v e n t for s c i n t i l l a t o r s .
Our p r o g r a m for the n e a r fu tu re i n c l u d e s :
1) T e s t i n g of n e w c o u n t e r s now c o m p l e t e d o r u n d e r
c o n s t r u c t i o n .
2) D e s i g n and c o n s t r u c t i o n of c o u n t e r s of l a r g e a r e a for u s e
a t C P - 5 w i th the f a s t c h o p p e r .
15
/s 3-4 T r a n s m i s s i o n Measuremen t s with the Fas t Neutron Velocity
Selector (5211-01, 5261-01)
Lowell M. Bol l inger , Duane Dahlberg , R. Ronald P a l m e r Reported by Lowell M. Bollinger
T r a n s m i s s i o n ineasu remen t s have been made with the fast
neutron velocity se lec tor during the p r e s e n t qua r t e r as follows:
Sample
Antimony
Thickness (gm/cm^)
12.5 12.5
Resolution (>Cs /m)
0. 14 0. 19
Energy Range (ev)
45-300 200-10,000
Comments
T r a n s m i s s i o n dips were observed at 50. 5 , 53. 5 , 6 4 . 0 , 7 4 . 0 , 7 6 . 5 , 9 0 . 0 , 105, 113, 128, 147, 166, and 190 ev. It is probable that those below 128 ev a r e caused by single r e s o n a n c e s .
Antimony-123 1.27 0. 14 45-300 T r a n s m i s s i o n dips were observed at 5 0 . 5 , 76. 5 , and 105 ev. See below for s u m m a r y of antimony isotopic ass ignment .
Bismuth
Magnesium
2. 4 9 .
8.
37 1
83
0. 0.
0.
14 14
13
205-30,000
3 ,000-30 ,000 No r e s o n a n c e , except the known resonance at 20 kev , was observed
Manganese 7. 71 0.099 0.0302
0. 0. 0.
14 14 14
200-30,000 No unrepor ted r e sonances were observed.
16
Sample
Niobium
Thickness (gm/cm^)
21 .6
Vanadium 15. 7 8.3 1. 03
Resolution (yUs/m)
0. 14
0. 13 0. 14 0. 14
ii.nergy Range (ev)
45-300
300-30,000 100-30,000 300-30,000
Comments
Resonances were observed at 35. 8, 119, and 195 ev. Comparison with t r ansmi s s ion data for thin tantalum sample shows that neither these nor p r e viously repor ted r e son ances at higher energy can be due to Ta. Small (T Q p values of observed resonances suggest that they a r e capture r e sonances .
Large resonances were observed at 4280, 6500, and 11,300 ev. Also very weak resonances were observed at 168 and 1440 ev. These la t te r resonances mus t be due to the 1 /47o abundant i sotope, V 50
Summary of Isotopic Ass ignments for Antimony Resonances
Resonance Energy
6.28 15.3 21 . 6 30. 0 50.5 53.5 64.0 74. 0
-
(ev)
Future
Isotopic As
Work
signment
121 121
123 121
123 121 121 121
Resonance Energy (ev)
76.5 90. 0 105 113 128 147 166 190
Isotopic Assignment
123 121
123 121 121
The sepa ra t ed isotopes of zinc will be studied.
17
/ - ;
5-3 (The Absorption and Scat ter ing of Neutrons by Hafnium) (5211-01, 5261-02)
Lowell M. Bol l inger , Sigmund P . H a r r i s , Car l T. Hibdon Car l O. Muehlhause
The a r t i c l e on this subject is in the p r o c e s s of publication in
The Phys ica l Review.
6-3 Spiral Velocity Selector for Slow Neutrons (5211-01)
Roy Ringo
The ro to r for this velocity se lec tor has been made sufficiently
rigid by an excellent copper braz ing job done by the General E lec t r i c
Company in Schenectady. The Centra l Shops Depar tment is now completing
the machine .
11-4 Instal lat ion and Operat ion of the Van de Graaff Generator (5211-01 , 5261-02)
1. Instabil i ty of the Posi t ion of the Ion Beam - F . Paul Mooring
The aluminum rings mentioned in the las t qua r t e r ly r epor t
have been insta l led in the high voltage sect ion of the acce l e r a to r tube.
Simultaneously, the pumping sys tem was improved. One or the other of
these changes cured the beam jumping p r o b l e m , mos t probably the instal la t ion
of the r ings . Whether or not additional t roubles have been introduced is
yet to be seen. Two that might be expected a r e a l imita t ion of the maximum
voltage that can be reached and an init ial dependence of the posit ion of the
beam on the energy of the genera to r .
18
2. The Corona System - F . Paul Mooring
The generat ing vo l tme te r , which allows the operator to monitor
the belt charging condi t ions , has been re ins ta l led . No further corona studies
a r e contemplated.
3. Inc rease of Voltage - F . Paul Mooring
No a t tempt to r e a c h proton energies grea te r than 3. 55 Mev has
been made so far .
4. The 90° E lec t ros t a t i c Analyzer - R. Ray Weeks
The 90° e lec t ros ta t i c analyzer having a radius of 40 inches
has been completed far enough, on November 14, to run a beam through it
and control the energy of the Van de Graaff machine. Thus far no at tempt
has been made to de te rmine exper imenta l ly the c ha r a c t e r i s t i c s of this
ana lyze r . Short cuts have been made in o rder to get the analyzer running
and make the eas t beam line immedia te ly avai lable. At p resen t the nnaximum
resolv ing power of the analyzer is not needed. A 4-inch diffusion pump,
a 4- inch va lve , the in te r io r of the cold t r a p , and the vacuum protect ive
c i rcu i t s a r e yet to be del ivered from the suppl ie rs . They will be instal led
as soon as p rac t i ca l after rece ip t .
5. Beam Cur ren t Integrator - Alexander Langsdorf, J r .
The p rec i s ion beam cu r ren t indicator has been completed
and is in regu la r u s e , and an ins t ruct ion manual has been p repared for it.
!1 6. Operat ional Exper ience - Jack R. Wallace
During this qua r t e r the Van de Graaff machine has been operating
successful ly in the energy range of approximate ly two mil l ion volts with a
proton beam c u r r e n t up to fifteen m i c r o a m p e r e s . These conditions fulfilled
the r equ i r emen t s of those exper iments scheduled for this per iod.
The t ime dis t r ibut ion for the var ious exper iments is as follows:
1. Total neutron c r o s s sect ions - Ca r l T. Hibdon 187.0 h r s .
2. Self detection exper iment - William A. Reardon 117. 0 h r s .
3. P ropor t iona l counter checking - Gilbert J. Pe r low 5. 1 h r s .
4. Crys ta l counters - Rober t E. Holland and F . Pavil Mooring 17. 1 h r s ,
5. Lining up of 90° e lec t ros ta t ic analyzer - R. Ray Weeks 8. 7 h r s .
6. Neutron exposure of Li p la tes - Victor E. Krohn 9. 6 h r s .
7. Lining up proton s p e c t r o m e t e r - Rober t E . Malm 1.4 h r s .
Total machine t ime 345. 9 h r s .
Exper imen ta l se t up t ime 31 . 3 h r s .
Time out of operat ion a t t r ibutable to difficvilties with
the machine 90. 0 h r s .
S ta r t -up t ime and daily maintenance 45. 8 h r s .
Time available : 64 days x 8 hours = 512. 0 h r s . 512.0 h r s . 512.0 h r s ,
The "out -of -opera t ion" t ime was mainly caused by th ree
difficulties.
20
1) The F r e o n a n d m o i s t u r e p e r c e n t a g e s w e r e too h igh in the
i n s u l a t i n g g a s . Th i s l e d to a c h e m i c a l r e a c t i o n on a l l b r a s s p a r t s in the
m a c h i n e . The p u l l e y s o v e r wh ich the ny lon c o n t r o l s t r i n g s t r a v e l w e r e b r a s s .
T h e n y l o n s t r i n g s d i s i n t e g r a t e d . The p u l l e y s have b e e n r e p l a c e d wi th a l u m i n u m
o n e s , and we a r e now k e e p i n g t h e gas m i x t u r e d r i e r and have r e d u c e d the
p e r c e n t a g e of F r e o n .
2) F a i l u r e of t h e 35 TG t u b e s in the o s c i l l a t o r for the ion s o u r c e .
The f i l a m e n t p r e s s i n the t u b e s c r a c k e d and a l l owed gas to e n t e r . The c a u s e
of t h e s e c r a c k s h a s no t y e t b e e n de f in i t e ly d e t e r m i n e d , b u t we a r e e n d e a v o r i n g
t o f ind and e l i m i n a t e t h i s s o u r c e of t r o u b l e .
3) J u m p i n g of the ion b e a m w a s c o r r e c t e d by i n s t a l l a t i o n of
r i n g s on the e l e c t r o d e s i n t h e h igh v o l t a g e end of the a c c e l e r a t i n g t u b e .
T h e p u m p i n g s p e e d of the a c c e l e r a t i n g tube w a s i n c r e a s e d by the r e m o v a l
of a baf f le .
12-4 (R. F . Ion S o u r c e for the Van de Graaff G e n e r a t o r ) ( 5 2 1 1 - 0 1 , 5261-02)
F . P a u l M o o r i n g
The ion s o u r c e i s in r e g u l a r u s e , and no f u r t h e r d e v e l o p m e n t a l
w o r k i s p l a n n e d . T h i s r e p o r t i s t he f ina l one for t h i s p r o g r a m .
14 -3 P u l s e d N e u t r o n B e a m s ( 5 2 1 1 - 0 1 , 5261-02)
R o b e r t E . H o l l a n d
The ion s o u r c e for the p u l s e d s y s t e m h a s b e e n o p e r a t e d
on the t e s t s e t u p , and the o s c i l l a t o r and p o w e r s u p p l i e s h a v e b e e n found
to be s a t i s f a c t o r y . H o w e v e r , t h e a r r a n g e m e n t for m e a s u r i n g the output
21
o2/
of the ion source was not sa t i s fac tory and is being rebui l t .
20-4 Energy States of Light Nuclei from Charged Pa r t i c l e Reactions (SUTTOI)
David R. Ingl i s , Robert E . Malm, Li l l ian Darlington Reported by Robert E. Malm
P r e l i m i n a r y m e a s u r e m e n t s of the s tabi l izing sys tem for
the magnet ic field and of the focussing p rope r t i e s of the 16-inch proton
spec t rome te r have been made by observing the shape and posit ion of the
a lpha-par t i c le l ines from Pu . The proport ional counter previously
used as a detector was rep laced by a sodium iodide c rys t a l and photo
mult ipl ier obtained from Mr. Robert S\vank of the Ins t rument Resea rch
and Development Division. When the p roper image posit ion w^as obtained,
the half-widths of the observed a lpha-par t ic le groups were a lmos t ent i re ly
the resu l t of widths of the source {^. 040 inches) and of the detector sl i t
(rJ . 040 inches).
The var ia t ion in t e m p e r a t u r e of the Alnico magnet in the
magnet ic f luxmeter during opera t ion was found to be much g rea te r than
had been anticipated. This t e m p e r a t u r e var ia t ion introduced appreciable
e r r o r s in our field m e a s u r e m e n t s . A f luxmeter , in which the t e m p e r a t u r e
of the Alnico magnet will be regu la ted , is being cons t ruc ted .
A number of t a rge t s have been p r epa red for use in exper iments
during the next q u a r t e r .
22
:3i 30-4 Scintil lation Coincidence Spect rometer (5211-01)
S. Bradley Burson and Willard C. Jordan Reported by S. Bradley Burson
In the previous r epor t it was noted that the cal ibrat ion of the
ins t rument drifted with t e m p e r a t u r e . The cause of this effect has been found
to be a negative t e m p e r a t u r e coefficient of the output of the power supply
for the high voltage applied to the RCA 5819 photomultiplier . The effect
IS a t t r ibutable to drift in the 5651 voltage s tandard in the power supply; this
tube will be placed in a thernaostat ical ly control led container in an effort
to el iminate the drift .
The r e p o r t to be published in the Review of Scientific Instruments
is in pa r t wri t ten .
31-4 (The 1.42 Min I somer ic State in -jjlr^^^) (5211-01)
S. Bradley Bur son , Berna rd H a m e r m e s h , Virginia Hummel , Willard C. Jordan Reported by S. Bradley Burson
No further work has been done in this p r o g r a m during the
quar te r .
32-4 Decay Scheme of 66Dy^^^"^ (1- ^ ^i^) and ^^Dy^^^ (2. 3 hr) (5211-01)
S. Bradley Burson , J. M. Cork (University of Michigan), Willard C. Jordan Reported by Willard C. Jordan
The r e su l t s of this study a r e summar ized in the las t
quar te r ly r epo r t (ANL-5140). A complete r epor t is scheduled for
publication in the December 1 i ssue of The Physical Review. This repor t
is the l a s t one on this p r o g r a m .
23
Ja3 35-4 Decay Schemes of Long-Lived R a r e - E a r t h Isotopes (5211-01)
Eugene L. Church
Examinat ion of the gamma spec t rum of f ission europium
by means of c r i t i c a l absorpt ion and with the c u r v e d - c r y s t a l spec t rome te r
in the Chemis t ry Division has failed to r evea l the s a m a r i u m x - r a y s which
should follow the in ternal convers ion of the 244. 4-kev t rans i t ion previously
r epor t ed in /^Sm . Long r e - e x p o s u r e of the convers ion-e lec t ron
spec t rum of no rma l and f iss ion europium at / t /0 . 2% momentum resolu t ion
indicates that two previous ly unresolved g a m m a - r a y s a r e p r e s e n t , one
convert ing in /^Sm^^^ and the other in Gd . These t r ans i t ions
have K-convers ion l ines which a r e identical within the above resolu t ion
and a r e dist inguishable only on the bas i s of their previously undetected
difference in L -conve r s ion e n e r g i e s .
The previous ass ignment of the 244. 4-kev t r ans i t ion as the
ground-s ta te t rans i t ion in /^Sm is in e r r o r . The p re sen t study indicates
1 CO
that this t r ans i t ion is in / ^Sm , in ag reement with the r e su l t s of Katz and 3
Lee . The above r e s u l t s , as well as the r e m e a s u r e d energ ies of the
cor responding ground-s ta te t rans i t ions in /^Sm^-'^ and f^A^^ , a r e shown
in Table II.
^ Analysis pe r fo rmed by P . P . Day.
^ ANL-5080, p. 32.
^ R. Katz and M. R. L e e , P h y s . Rev. 85 , 1038 (1952).
24
Table II
Trans i t ion Energ ies in kev
Nucleus 1st Exci ted State 2nd Excited State Ratio
/^Sm^^^ 121.8 244.4 2. OO.7
64Gdl54 123.4 247.7 2. OOy
The E2 c h a r a c t e r of the t rans i t ions observed , as well as the
known energy sys temat ics of even-even nuclei in this region of the periodic
t ab l e , make probable the E 2 - E 2 cascade ass ignment indicated in Table II.
The deviation of the energy ra t ios fronn the value 7/3 predic ted by Bohr and
5 Mottelson for pure rotat ional s ta tes is a lso cha rac t e r i s t i c of the r a r e - e a r t h
region.
The s t r ik ing s imi l a r i t y of the excited s ta tes of the nuclei
cons idered is in ag reement with G. S. Goldhaber 's observat ion that the
addition of two protons may have l i t t le effect on the energy level spec t rum of
, . 4 even-even nuclei .
36-4 The Decay Schemes of Mass 48 Nuclei (5211-01)
Harvey C a s s o n , Leonard S. Goodman, Victor E. Krohn Reported by Harvey Casson
A paper on this work is expected to appear in the Physical Review
for December 15, 1953.
^ G. S. Goldhaber , Phys . Rev. 9_0, 587 (1953).
^ A. Bohr and B. Mottelson, Phys . Rev. 89, 316(1953).
25
J2S
38-2 The Radiations from ^^Tb^^^ (5211-01)
S. Bradley Burson
F u r t h e r in ternal convers ion studies yielded lines for gamma-
rays of 93 and 391 kev, as well as m o r e accura te energy values for some
of the t rans i t ions a l ready repor t ed .
F u r t h e r g a m m a - g a m m a coincidence studies indicate that the
196-kev g a m m a - r a y is in coincidence with the 215-kev rad ia t ion , and
that the 298-kev peak is not in coincidence with ei ther of these as was
thought e a r l i e r . There is some indication that 759-kev g a m m a - r a y is in
coincidence with the 196 and 215-kev g a m m a - r a y s .
Decay Scheme The decay scheme indicated in the figure 2 is
well substant ia ted by the exper iment in mos t r e s p e c t s . The por t ion indicated
by heavy l ines is cons idered to be well es tab l i shed , while the r emainder
is not so ce r t a in .
The six t rans i t ions forming the dark port ion of the scheme
a r e grouped as follows: the energy difference from in ternal convers ion
between the 1.17 and the 1. 26-Mev t rans i t ions is equal to 86. 3 kev within
exper imenta l l im i t s . The s a m e is t rue for the difference in energy between
the 873 and 960-kev t r ans i t i ons . In both c a s e s , coincidences a r e shown
to exist between the 86. 3-kev radia t ion and the lower energy g a m m a - r a y
of each pa i r . The difference in energy between the 960-kev and the 1. 26-
Mev t rans i t ions is equal within exper imenta l l imi ts to 298 kev , and the
l a t t e r radia t ion is found to be in coincidence with the 873 and 960-kev
g a m m a - r a y s , as well as the 86. 3-kev radiat ion. Thus the six t r ans i t ions
^4
26
65 Tb
160
FIG. 2 PROPOSED DECAY
SCHEME FOR
160
^ TbJTIdoy) 65
66 Dy
160
71 day
)8» 520 kev
)8«i860kev
298
1174
1265
LEVEL ENERGY in kev
— 1258
391
759
957 960
873
' '
86.3 4,
• *
960
867
282 I
375 I
196
LI
_1 497
301
410 215
86.3
0
27
57 form a closed sy s t em cons is tent with both energy differences and coincidence
expe r imen t s . The 86. 3-kev t r ans i t ion is cons idered to be the ground s tate
t rans i t ion . Its s t rong intensi ty along with theore t ica l cons idera t ions a r e in
support of this assumpt ion . The energy difference of 298 kev r equ i r ed between
the two beta b ranches is cons idered to be within exper imenta l l imi t s of the
m e a s u r e m e n t s of the beta spec t rum. The previously r epor t ed low energy
beta component of 396 kev does not fit into the scheme; its existence is now
cons idered to be doubtful.
In the light of the conclusions a l ready d i scussed , it is difficult
to explain the exper iment indicating that the 215-kev is in coincidence with
the 960-kev radia t ion. It can be s e e n , however , that if the 215-kev t rans i t ion
is c o r r e c t l y placed above the 86. 3 , the energy difference between the 301-kev
s tate and the highest excited s tate is about 957 kev, and a t r ans i t ion between
these two s ta tes can account for the coinc idences . A g a m m a - r a y of this
energy would, of c o u r s e , be indist inguishable f rom the 960-kev rad ia t ion
and ex t remely difficult to reso lve f rom it by in terna l convers ion m e a s u r e m e n t s .
That the 196-kev g a m m a - r a y belongs immedia te ly above the
215-kev g a m m a - r a y is indicated by the exis tence of the 410 t r ans i t ion (the
sum) and the fact that they a r e in coincidence with each other .
The coincidence m e a s u r e m e n t s involving the 759-kev
gamnna-ray a r e inconclusive and difficult to i n t e rp re t because of the intense
Compton peak f rom the higher energy rad ia t ions . The exper iments do provide
co r robora t ive evidence , however , that the a r r a n g e m e n t is c o r r e c t . The
other t rans i t ions a r e fitted in on the bas i s of the i r energ ies alone.
28
The study is cons idered comple te , and the final r esu l t s have
been wr i t ten up and a r e in the p r o c e s s of being submitted for publication in
the Phys ica l Review.
40-2 The Decay Scheme of 23V^^ (5211-01)
S. Bradley B u r s o n , J. M. Cork (University of Michigan), Willard C. Jo rdan , J ames M. LeBlanc Reported by James M. LeBlanc
A m o r e careful study of the gamma spec t rum of 3. 7-min V^
has been naade with the 10-channel scint i l lat ion spec t rome te r . This
s p e c t r u m shows the p r e sence of the 1.41-Mev g a m m a - r a y repor ted in
the l a s t qua r t e r ly r epo r t . No other g a m m a - r a y s were observed. The
1. 41-Mev g a m m a - r a y was found to be in coincidence with b e t a - r a y s .
It was expected that the 2. 6-min activity repor ted by Renard
might be observed in samples i r r ad i a t ed with neutrons for per iods of about
1 or 2 minu tes . I r rad ia t ion of V in C P - 3 ' for per iods of 1 minute , 3 minu te s ,
and 10 minutes were made and found to produce act ivi t ies of half- l ives
3. 7, 3. 5 , and 3. 7 min , r e spec t ive ly , with no indication of the p resence of
an activity with a half-life of 2. 6 min.
In a r ecen t papery Schwager and Cox repor t that they find no
evidence for such a 2. 6-min metas tab le s ta te resul t ing from a (d,p) reac t ion
on V.
G. A. Renard , Amm. Phys . 5_, 385 (1950). J. E . Schwager and L. A. Cox, Phys . Rev. 92, 102 (1953).
41-2 The Decay Scheme of 48Cd^^'^ and 49111^^^ (5211-01)
S. Bradley B u r s o n , J. M. Cork (University of Michigan), J ames M. LeBlanc Reported by James M. LeBlanc
Work on this decay chain has been comple ted , and a paper will
be wr i t ten for submiss ion to the Phys ica l Review. The information obtained
is s u m m a r i z e d in the energy level scheme shown in F igu re 3. The only
g a m m a - g a m m a coincidences expected but not observed a r e those between
the 0.425 and 0. 84-Mev g a m m a - r a y s ; the 0. 84-Mev g a m m a - r a y , however ,
was too weak for such coincidences to be observable . There a r e , however ,
two g a m m a - r a y s of energy 0. 276 and 0. 330 Mev which were found to follow
beta decay from Cd that a r e not included in the scheme . F u r t h e r m o r e
the energy fit for the 2. 0-Mev g a m m a - r a y is r a the r poor , so that i ts
p lacement as indicated must be cons idered doubtful.
43-1 The Decay of the 3. 5-min Metastable State of Sb^^^ (5211-01)
S. Bradley B u r s o n , J. M. Cork (University of Michigan), Willard C. Jo rdan , James M. LeBlanc Reported by James M. LeBlanc
The 3. 5-min metas tab le state in Sb has been previously
studied by two g roups , one with a scint i l la t ion spec t rome te r and the other
with an ion chamber . ^ The r e su l t s with the scint i l la t ion spec t rome te r
indicated one g a m m a - r a y of 68 kev , whereas those of the ion chamber study
indicated two g a m m a - r a y s of 59 and 74 kev.
^ E. der Mateosian and M. Goldhaber , Phys . Rev, 82 , 115 (1951).
J. H. Kahn, Oak Ridge National L a b o r a t o r y , ORNL-1089, (Nov. 1951).
o
(O o in
/
o GO
CM
to
lO CM
•
o o - t o *
c> W * ^ Si l
Q i : :
ro
LL.
31
3/
Samples of this activity were obtained by i r rad ia t ing enr iched
Sb in the C P - 3 ' . They were then studied with a 180° photographic s p e c t r o
me te r and the 10-channel coincidence scint i l la t ion s p e c t r o m e t e r . Two con
ve r s ion e lec t ron lines were observed which a r e in te rpre ted as K and L l ines
for a 76-kev g a m m a - r a y . The scint i l la t ion spec t romete r study showed a
s t rong x - r a y peak plus a gamma peak at about 60 kev. The gamma peak was
d is tor ted on the high energy s i d e , apparent ly by the p re sence of the 76-kev
g a m m a - r a y . X - r a y gamma coincidence exper iments were pe r fo rmed and
showed that the gamma peak was in coincidence with the x - r a y s . Since the
60-kev g a m m a - r a y itself is not internal ly conver ted to any cons iderab le
extent , these coincidences indicate prompt success ive ennission of 60-kev
g a m m a - r a y s and x - r a y s produced by in terna l convers ion of the 76-kev
g a m m a - r a y s . Apparent ly , the metas tab le state decays by emis s ion or
convers ion of the 76-kev g a m m a - r a y , this t rans i t ion being followed
prompt ly by emis s ion of the 60-kev g a m m a - r a y . The con t ra ry hypothesis
would r equ i re no appreciable in te rna l convers ion of a 3. 5-min metas tab le
s ta te and considerable in te rna l convers ion of a ve ry shor t - l ived succeeding one,
both somewhat improbable .
Longer exposures a r e being made with the 180° s p e c t r o m e t e r
with the hope of detecting the 60-kev g a m m a - r a y and obtaining good enough
K and L lines for the 76-kev g a m m a - r a y to allow a K/L m e a s u r e m e n t .
32
3^
45-1 The Shor t -Lived Activit ies of Zn (5211-01)
S. Bradley Bur son , J. M. Cork (University of Michigan), Willard C. Jo rdan , James M. LeBlanc Reported by James M. LeBlanc
The shor t - l ived act ivi t ies of Zn have been previously
studied with varying degrees of comple teness . The 14-hr and 52-min
act ivi t ies of Zn " have been invest igated in some detail by severa l g roups ,
whereas Z n ' ^ has been examined only by absorpt ion and half-life s tudies .
69 Zn has been found to have a metas tab le s ta te which decays by the
emiss ion of a 437-kev M4 t rans i t ion to the ground s ta te . The ground
s ta te then decays by beta emis s ion to Ga " . No gamnna-rays have been
71 found to follow this b e t a - r a y . In the case of Zn , a half-life of 2. 2 min
has been ass igned and a b e t a - r a y of 2. 1 Mev measu red by absorption.
G a m m a - r a y s were detected but not measu red .
The p resen t work has been concerned mainly with the
71 study of Zn . The sources were obtained by i r rad ia t ing both ordinary
Zn and enriched Zn'^° (48.4% Zn'^^ and 29% Zn^^) in C P - 3 ' . Since
70 o rd inary Zn contains only 0. 62% Zn and its c ros s section for neutron
71 cap ture is 0. 09 b , very l i t t le Zn is formed by neutron capture in
o rd inary Zn.
The gamma spec t r a of these sources were studied with
the 10-channel scint i l lat ion s p e c t r o m e t e r , and the be t a - r ays were studied
70 by absorpt ion in Al. In a l l , four act ivi t ies were found in the enriched Zn
33
s a m p l e s , 2 .2 min , 1 h r , 3 h r , and 14 h r . The 1-hr and 14-hr act ivi t ies
a r e due to Zn°° and appeared both in enr iched Z n ^ and in ord inary Zn
s o u r c e s . On the other hand, the 2. 2-min and 3-hr decays were found
70 only in the enr iched Zn " s a m p l e , and a r e therefore to be ass igned to
Z n ^ l .
Since the 14-hr and 1-hr act ivi t ies appeared in all of the
s a m p l e s , it was n e c e s s a r y to examine thei r photon spec t r a and coinci
dence s p e c t r a , in o rde r that the re be no confusion.
14 h
The photon spec t rum of the 14-hr decay was obtained and
compared with that of Au " , which has a s t rong gamnna-ray of energy
411-kev. It was found that the 14-hr activity has only one g a m m a - r a y
of about 435 kev as previous ly r e p o r t e d , and that it is not coincident with
b e t a - r a y s . This is in ag reemen t with previous r e s u l t s .
52 m
There were no g a m m a - r a y s detected which could be
ass igned to this activity. Very s t rong b e t a - r a y s were found and their
energy m e a s u r e d by absorpt ion to be about 0. 85 Mev. This ag rees with
previous work.
34
2.2 m
The photon spec t rum of the 2. 2-min activity is found to
show the p re sence of four g a m m a - r a y s of energy 0. 12, 0. 5 1 , 0 .90 , and
1.05 Mev. Of these g a m m a - r a y s the 0. 51-Mev one is the s t rongest .
B e t a - g a m m a coincidence m e a s u r e m e n t s showed that all of the gamma-
rays a r e coincident with b e t a - r a y s . The resu l t s of Al absorption expe r i
ments on the b e t a - r a y s indicate a maximum beta energy of 2. 4 ± 0.2 Mev.
The Al absorpt ion curve for the b e t a - r a y s coincident with the 0. 51-Mev
gannma is not significantly different from the absorpt ion curve for single
counts . Because of the rapid decay of the s amp le , s ta t i s t ics on these
curves a r e not good enough to de termine if there is any branching to the
ground s ta te . The 0. 12-Mev g a m m a - r a y is not in coincidence with the
0. 51-Mev g a m m a - r a y .
3 h
The th ree -hour activity is found to decay by the emiss ion
of a 1. 5-Mev b e t a - r a y which is followed by three g a m m a - r a y s of energy
0. 38 , 0. 49 , and 0. 61 Mev. It is found that all three of these gamma-
rays a r e in coincidence with each o ther , indicating that they a r e in
ca scade . In addition, the be t a -gamma coincidence absorpt ion curves
indicate that the 1. 5-Mev b e t a - r a y is in coincidence with all th ree of
these gannma-rays .
35
46-1 The Decay of 32^6*'"^ (12 hr) and 22Ge^^"^ (59 sec) (5211-01)
S. Bradley B u r s o n , Willard C. Jo rdan , James M. LeBlanc Reported by S. Bradley Burson
76 Neutron bombardment of 32^^ re su l t s in the production of
77 32Ge , which exis ts as a metas tab le s ta te with a half-life of 59 seconds and
a grotind s tate with a half-life of 12 hou r s . The metas tab le s ta te decays both
77 by an isonneric t rans i t ion of about 380 kev to the ground s ta te of Ge and
77 77 by a beta t rans i t ion of about 2. 8 Mev to As . The ground s tate of Ge ' '
77 decays by means of 3 beta b ranches to As . Numerous gannnna-rays have
77 been repor t ed to be assoc ia ted w^ith the excited s ta tes of As . We have
under taken to study these act ivi t ies by means of our photographic s p e c t r o
m e t e r s and the scint i l la t ion coincidence s p e c t r o m e t e r .
To date we find that two radia t ions of about 213 and 268 kev ,
a s soc ia t ed with the 12-hour ac t iv i ty , a r e in coincidence with each o ther .
The 213-kev g a m m a - r a y seems a lso to be in coincidence with a g a m m a - r a y
of about 410 kev. Both the 213 and 268-kev radiat ions a r e a lso in coincidence
with other g a m m a - r a y s whose energy is in excess of 800 kev.
The gannma-ray of about 73 kev repor t ed by Smith is not found
to be p resen t . It is suspected that the radia t ion of this energy r epor t ed in
that study was in fact K x - r a y s of Pb caused by convers ion in the lead r a d i a t o r ,
77 r a t h e r than a t r ans i t ion in As
A. B. Smith, Phys . Rev. 86 , 98 (1952),
36
50-4 (Internal Convers ion of Capture Gannma-Rays Associa ted with Gd) (5211-01)
Car l T. Hibdon
No work was done on this p r o g r a m during the past qua r t e r .
51-4 C h a r a c t e r i s t i c s of a Scintil lation Counter Spect rometer (5211-01)
B e r n a r d Hamernnesh and Arthur L. Recksiedler Reported by Arthur L. Recksiedler
No change in the operat ing procedure has been made with the
l a rge Nal c r y s t a l . However , s tudies have begun using the la rge c rys t a l
and 20-channel analyzer in coincidence with a smal l c rys t a l ( 3 / 8 " x 1-1/2"
d iamete r r ight cylinder) and a s ingle-channel analyzer .
52-4 Neutron Capture Gamma-Ray Studies with the Scintillation Spec t rometer (5261-02)
Be rna rd Hannermesh and Arthur L. Recksiedler Reported by Arthur L. Recksiedler
Work has continued on the study of the capture g a m m a - r a y
spec t r a using the l a rge c r y s t a l , with F e , Cu, and Co observed during the
per iod . No new l ines were found in Fe or Cu. There appears to be a
l ine in Co at 2. 1 Mev not previous ly repor ted .
Chlorine and cadnnium have been studied so far for coincidences
between l ines previously found. No definite s ta tement can be made ye t ,
and work is continuing on these e l ements .
A l e t t e r to the editor of the Physical Review on the capture
g a m m a - r a y s f rom hydrogen appeared in the October 15 i s sue .
37
J7 60-4 E igh t -Mete r Bent C r y s t a l Spec t rometer (5261-02)
B e r n a r d H a m e r m e s h and David Rose Reported by B e r n a r d H a m e r m e s h
The detailed design was completed during the q u a r t e r , and all
of the sub-assennbl ies a r e under const ruct ion. One-half of the shop work has
been completed.
When the base cas t ing has been located proper ly in building
330, which will be done in the next month , it will be possible to a s semble
all of the heavy sect ions of the ins t rument and instal l the shielding. This
work will be done and the var ious drive sys t ems will be tes ted during the
next qua r t e r .
70-4 Measurements of Nuclear Moments by Angular Cor re la t ion (5211-01)
Victor E . Krohn and Sol Raboy Reported by Sol Raboy
The angular co r r e l a t i on between the two g a m m a - r a y s
204 emit ted in cascade from the i somer i c state of Pb is being studied.
The ini t ial phase of the work included the study of the effects of var ious liquid
media and finally the effect of a magnetic field. This l as t effect can yield
a quantitative m e a s u r e of the nnagnetic moment of the f i rs t excited s ta te of
Pb204.
The r e su l t s r epor t ed in the las t quar te r ly were not in
agreennent with those obtained by Frauenfe lder .
F rauenfe lde r , J en t s che , Lawson, and DePasqua l i , p rep r in t s of l e t t e r submit ted to The Phys ica l Review for publication; F rauen fe lde r , J en t sche , Lawson, and DePasqua l i , Phys . Rev. 92 , 513 (1953).
38
Since fur ther m e a s u r e m e n t s of the anisotropy of the two
g a m m a - r a y s (900 kev and 370 kev) did not reproduce his r e s t i l t s , a s e r i e s
of exper iments was pe r fo rmed to gain information as to the var ious act ivi t ies
p r e s e n t in the bombarded Tl foil.
A new set of operat ing conditions was determined. One
counter accepted everything above 600 kev, and the second counter was set
to accept pulses in the region of 320 kev to 420 kev. F u r t h e r m o r e , the
f i r s t counter was delayed by 0. 3 Ztsec. Ta foil and Pb sheet were combined
to shield the co\inters f rom low energy gannma-rays and x - r a y s .
The anisotropy of the two gammas was measu red for foils
dissolved in concentra ted HNO3 ^^^ a l so in concentrated H2SO4. The
anisot ropy is m e a s u r e d by the ra t io of the number of coincidences at 180°
to the number at 90°. Since the measu remen t s were done in the p resence of
the m a g n e t , s imi l a r data were taken for the two liquid media on a plywood
table with the amount of neighboring sca t t e r ing ma te r i a l minimized. The
r e s u l t s a r e as follows. They have not been co r r ec t ed for solid angle. «
Anisotropy Liquid medium in Exper imenta l which source is conditions dissolved
1. 25. ± . 03. Concentra ted HNO3 In p resence of magnet but without magnetic field.
1. 26 ± . 04 " HNO3 ^^ ^^^* plywood
1.24 ± . 03 " H2SO4
table . 1.23 ± .04 " H2SO4
31^ These r e su l t s indicate that within the exper imenta l e r ro r
the re is no difference between HNO3 and 'H-^OA solut ions. F u r t h e r m o r e ,
sca t te r ing by the magnet does not lead to a significant change in the observed
anisotropy. The differences between these r e su l t s and Frauenfe lder s t i l l
exist and a r e not unders tood.
Some data with the nnagnetic field applied have been obtained.
The effect of the magnet ic field on the angular co r r e l a t i on has been observed
and is being studied quantitatively as a function of field s t rength. The
meager data obtained so far do not pe rmi t plotting of a nneaningful cu rve .
These s tudies will be c a r r i e d on in the next q u a r t e r .
It is planned to study the cascading g a m m a - r a y s f rom Pb204m
in liquid T l , i. e. , nnelted T l , s ince such mel t s should give min imum d i s to r
tion of the angular co r re l a t ion .
71-4 The Angular Cor re l a t ion of (3-Rays and Delayed Neutrons fronn Br ° ' _ _ _ _ _
Leonard S. Goodman
No further work has been done on this during the pas t
qua r t e r .
80-4 Molecular Beam Studies (5211-01)
John A. Dalman, Leonard S. Goodman, Sol Wexler Reported by Leonard S. Goodman
Measurement of the spin of Cs was s t a r t ed in the
las t q u a r t e r . Although a radio frequency resonance was obse rved , the
definite ass ignment of the spin of this isotope \vill r equ i re fur ther work.
40
The difficulties of in te rpre ta t ion have involved a combin
ation of p rope r t i e s of the equipment and proper t i es of this par t i cu la r nucleus.
The exper imenta l method, ^ ' ^ when rea l ized in a p rac t ica l
appa ra tu s , causes a b read th of the resonance due both to the finite length
of t ime the a tom is exposed to the R. F . field and to inhomogeneities of
the ideally unifornn magnet ic field.
In this pa r t i cu la r appa ra tu s , the inhomogeneous nnagnetic
fields a r e energized by e lec t ronica l ly regulated cu r ren t suppl ies . The
inhomogeneous magnets induce considerable nnagnetic field in the gap of the
homogeneous magnet . This induced field must be biased out by adding
c u r r e n t in the windings of the homogeneous nnagnet. Small percentage
drifts of the inhomogeneous fields occur red and caused drifts in the
homogeneous field which were la rge enough to make the resolut ion of the
appara tus nnuch poo re r .
F o r many isotopes the resolut ion would st i l l have been
sufficient to reso lve between the var ious possible nuclear sp ins . For
Qgl34m^ however , the spin is l a rge (7 or 8 is predicted from -y and (3-ray
sys temat ics ) and, as will be shown below, the demands on the resolut ion
become g rea t e r .
F o r very sma l l magnetic field the resonance which will
allow us to detect a change in s ta te occurs at the frequency-i/= 1. 4 H m c / s e c . ~~F
_ . J. R. Z a c h a r i a s , Phys . Rev. 6j_, 270 (1942).
2 L. Davis , J r . , D. Nagle , J. R. Z a c h a r i a s , Phys . Rev. 76, 1068 (1949).
41
F o r the e lec t ronic J = 1/2 the max imum F for spins 6, 7,
8 would be 6 , 5 , 7 . 5 , 8. 5 , the r ec ip roca l s of which a re 0. 154, 0. 133, 0 .118.
The sma l l differences between the r ec ip roca l s means smal l differences
between the resonant f requencies . If a field were to be used so that the
resonance for spin 7 would conne at 1 nnc / s ec , the differences would be l ess
than the width at half maximum for the bes t s imi l a r apparatus so far desc r ibed
in the l i t e r a t u r e .
The obvious thing to do is to go to higher magnetic f ields.
Unfortunately the deviation from l inear i ty for smal l homogeneous fields is
propor t ional to the sp in ,T/ = 1 . 4 H M + 1 . 4 H 2 1 "7 . If the hyperfine
~F ' ~ F ^n) J
spl i t t ing, /l-O , is at all sma l l the quadrat ic field t e r m becomes prominent at
re la t ively sma l l f ields. Theore t ica l predic t ions by Dieter Kurath a r e that a
very likely value ior A-\) would be as snnall as 1200 m c / s e c . Assuming this
vcdue ior A") and Va t resonance for I = 7 as 10 m c / s e c , we would have - Ja t
resonance for 1 = 6 and I = 8 as 11. 5 and 8. 8 mc / s e c , r e spec t ive ly , or -y)/ -
1 / ^ = 1 . 5 m c / s e c and TZ-y - "VQ = 1 - 2 m c / s e c . The quadrat ic t e r m , assuming 1 = 7 , contr ibutes approximately 10 x 10 x 14 = 1. 17 m c / s e c . The
1200 hyperfine split t ing may of cour se be ei ther s m a l l e r or l a r g e r than the
a s sumed va lue , and since we do not know.^ i ' a p r i o r i , the exper iment mus t
be extended to the finding of resonances over a wide range of f ie lds , but
will eventually pernnit the deternnination of both 4"vand I.
42
90-4 Cros s Sections for 14-Mev Neutrons (5211-01)
Harvey Casson , Leonard S. Goodman, Jack Haugsnes Reported by Harvey Casson
An RF ion source has been const ructed and is being tes ted
p r io r to instal la t ion in the acce l e r a to r .
Aside f rom the construct ion of the RF ion s o u r c e , nnost
of the work on this projec t during the past quar te r has been trouble shooting.
The unsat is fac tory opera t ion of the acce le ra to r has included (1) the
appearance of leaks in the vacuum sys tem; (2) e lec t ron loading of the power
supplies for the probe and f i rs t lens due to the l a rge unfocussed component
of the ion beann which caused unstable operation; and (3) ext remely shor t life
of the fi lament in the ion s o u r c e .
Since insufficient t rapping of oil vapors from the diffusion
punnp is bel ieved to be respons ib le for the shor t fi lament l i fe, the Dry
Ice t r ap is being conver ted into a liquid ni trogen t r ap .
With the ins ta l la t ion of the new t r ap and ion source it is
hoped that most of the aforementioned difficulties will be overcome.
91-4 Neutron Transpor t Cross Sections (4110-22)
Alexander Langsdorf, J r .
The equipment designed in the previous quar ter is near ing
complet ion in the shops and should be assembled during the next quar te r .
92-4 (Neutron Scat ter ing Cros s Sections by Use of the Scattering Chamber) _ _ _ _ _ _
Car l T. Hibdon
No work has been done in this p r o g r a m during the qua r t e r .
43
96-4 (Pile Absorpt ion C r o s s Sections) (5261-01)
David Rose
No work has been donfe on this p r o g r a m during the pas t
qua r t e r .
98-3 Total Neutron Cros s Sections in the kev Region (5211-01, 5261-02)
Alexander Langsdorf , J r .
See complete r e po r t by Car l T. Hibdon.
The tantalunn cups a r e on hand and will be used in future
work.
The 36 new boron tr i f luoride propor t ional counters a r e on
hand and will be ins ta l led in anticipation of future work.
98-3 Total Neutron Cros s Sections in the kev Region (5211-01, 5261-02)
C a r l T. Hibdon and Alexander Langsdorf , J r . Reported by Car l T. Hibdon
Measurennents of total neutron c r o s s sect ions in the kev
energy region as descr ibed in ANL-5080, I-98-2,have been continued. For
the p resen t work the only monitor used was a long counter placed beyond the
t a rge t along the d i rec t ion of the proton b e a m , the monitor previous ly used
with its axis at an angle of 120° with r e spec t to the proton beam having
developed t roubles which were not readi ly r epa rab l e .
Although the exact energy resolu t ion at tained in these m e a s u r e
ments is not known accu ra t e ly , it can be infer red from c e r t a i n of the observed
var ia t ions of c r o s s sect ion with energy that the sp read of energy is s o m e -
44
what l e s s than the nneasured thickness of the ta rge t . (The neutrons in
the 120° direct ion have a s m a l l e r sp read of energy than that of the incident
protons because of the motion of the center of m a s s of the interact ing pa r t i c l e s . )
The m e a s u r e d ta rge t th ickness var ied from 1 to 2 kev, and was most ly around
1. 3 kev.
The actual energy region covered was for nnost elements
from approximately 1 kev to 160 kev. Since Ti and Ni have a number of
well known r e s o n a n c e s , one or the other of these e lements was usually
m e a s u r e d along with each of the other sannples, the location of the resonances
in Ti or Ni serving as a check on the energy sca le . Insofar as possible
samples were chosen to allow a t r a n s m i s s i o n near 50%.
The one outstanding r e su l t of this p r o g r a m is that generally
all r e sonances observed a r e much na r rower than they had previously been
observed to be .
All the neutron energ ies given in the following a r e mean
neutron ene rg ie s .
The theore t ica l in te rpre ta t ion of the data is being worked on.
Beryl l ium
Transmi s s ion c r o s s sect ions for bery l l ium were measu red
in the energy region fronn 1. 6 to 55 kev. The c r o s s sections in this energy
region averaged to slightly l e s s than 6 b. No indications of a resonance
were found.
45
Boron
The c ro s s sect ion of B4C was m e a s u r e d up to I6O kev. At
each energy sett ing the c r o s s sect ion of C was a lso nneasured. The c r o s s
sect ion of B was then calculated f rom the two m e a s u r e m e n t s . Small
i r r e g u l a r i t i e s in the c r o s s sect ion curve below 10 kev were observed. The
t rend of the c r o s s sect ion ranged from about 6 b at low energ ies to l e s s than
4. 5 b at 160 kev.
Since a smal l amount of B ' ^ (96% enriched) was ava i lab le ,
the neutron t r a n s m i s s i o n c r o s s sect ion of this isotope was m e a s u r e d f rom
about 1 kev to 10 kev. The total c r o s s sect ions found a r e quite i r r e g u l a r and
may indicate the p r e s e n c e of n a r r o w r e s o n a n c e s . These indications should
be r ega rded as tentative until fur ther m e a s u r e m e n t s a r e m a d e , pa r t i cu la r ly
since the t r a n s m i s s i o n s of the sample were high, ranging from about 65 to
89%. Peaks were observed at 1, 1.8, 2. 5 , 3. 5 , 4. 5 , 6, and 8 kev. The
genera l t r end is not in accord with the 1 law. V
Carbon
The t r a n s m i s s i o n c r o s s sect ion of carbon does not
indicate the p r e sence of any r e s o n a n c e s . The c r o s s sect ion drops
slightly but s teadi ly f rom about 5 b near 1. 5 kev to l e s s than 4 - 1 / 2 b at
160 kev.
F luor ine
Measu remen t s were made with teflon (rJCF2) and
c o r r e c t e d for the effect of sca t t e r ing by the carbon a toms to get the
c r o s s sect ions for f luorine.
46
The total c r o s s sect ion of fluorine in the region from
1. 5 to 160 kev exhibits th ree la rge resonances at 28, 49 , and 98 kev. The
nneasured peak c r o s s sect ions of these resonances a r e 28, 33, and 26 b ,
r e spec t ive ly , and the m e a s u r e d widths at half maximum are 2 . 5 , 5, and 12
kev, respec t ive ly . These resonances have been observed previously but
with poore r solution (AECU-2040). An at tempt was made to assign/Cvalues
to these resonances based on the maximum observed peaks . On the basis
of the peak height of the resonance at 28 kev, its possible theore t ica l height ,
and the spin of the fluorine atom (1 /2) , t h e ^ v a l u e is indeterminate favoring
-^= 1. The peak height of the resonance at 49 kev indicates a value of
X = Q with J = 1 and g = 3/4 where g = 2J + 1 = the s ta t i s t ica l (21 + 1) (2S + 1)
weight factor . The m e a s u r e d peak height of the resonance at 98 kev is of
the c o r r e c t height f o r ^ = 0, g = 3 /4 , J = 1.
The observed c r o s s sect ion of fluorine up to 25 kev is
constant at about 3.7 b.
Titanium
Cros s sect ions for Ti were measu red for energies up to
55 kev. In addition to the previously known prominent resonances at 18 and
22 kev, o thers were found at *>;3. 5 , • f 8 . 7, 38, and 52 kev.
The peak values found for the two la rge resonances at 18
and 22 kev a r e 106 and 66 b , respec t ive ly . The respect ive widths at half
maximum of the two resonances a r e 4 and 3 kev (as es t imated crudely
f rom the half-value posit ions on the high and low s ides of the pa i r ) . The
inc rease of the peak value for the 18-kev resonance over the previously
47
^7 observed value of 85 b is to be a t t r ibuted to improved resolut ion in the
p resen t exper imen t s . If these two resonances a re to be a t t r ibuted to the
48 re la t ively abundant isotope Ti , the cor responding isotopic peak c r o s s
sect ions a r e 144 and 90 b , respec t ive ly .
Both the 38 and 52-kev resonances show the an t i - resonance
dips c h a r a c t e r i s t i c of S neut rons . Their widths at half nnaximunn a r e l e s s
than 4 kev.
Nickel
C r o s s sect ions were nneasured for Ni for energ ies up to
160 kev. The following table gives the pr incipal r e s u l t s .
Table III
Energy of peak (kev) Comments
Probably Co impuri ty 4. 5. 7.
^^12. 16 29 65
98 110 125 140 160
5 5 8 5
Peak value 85 b Small but c lea r ly reso lved Deep S-wave an t i - resonance dip
Ant i - resonance S->vave dip II II II II II
The peak at 65 kev is highly reso lved with a deep (2. 08 b
at 58 kev) an t i - r e sonance dip. This dip together with the observed peak
ass igns the^c value equal 0 with g = 1 and J = 1/2. Five other r e sonances
48
a re resolved: one at 98 kev , one at 110 kev, one at 125 kev, one at 140 kev,
and one at 160 kev. The l a t t e r two a re c lear ly S-wave with a minimum at about
155 kev of 1.3 b. This min imum is probably an interference dip between
the two r e sonances .
Zi rconium
The total c r o s s sect ion of z irconium from about 1 kev to
9-1/2 kev shows resonances c lea r ly at 2. 8, 4. 6, 7. 3 , and l e s s c lear ly at
6 and 8.8 kev. Resonances a r e a lso indicated in the 1 to 2-kev region. The
sample of z i rconium used has a hafnium content of less than 300 ppm.
Bismuth
The total neutron c r o s s section of bismuth from 1 to 55 kev
shows prominent resonances at 2. 5 , 1 2 . 5 , 16, 34, and 47 kev with l e s s e r
ones near 4 to 5 kev, s eve ra l between 20 and 30 kev, and one at 43. 5 kev.
The ones at 12. 5 and 34 kev a r e preceded by deep an t i - resonance dips.
99-2 Standards for Measuremen t of Thermal Neutron Absorption
Cros s Sections (5261-01)
Roy Ringo
This p rob lem is waiting rechecks of their work by
Harwel l and A. B, A tomenerg i , Stockholm.
4^ 100-1 The C r o s s Section of the Li (n,a) T Reaction (5211-01)
Robert E. Holland and F . Paul Mooring Reported by F . Paul Mooring
It was proposed to m e a s u r e the Li (n,a) T c r o s s sect ion
in the following manner . Since a l i thium iodide c r y s t a l counts neutrons by
means of the L i ° (n,a) T r eac t ion , its counting efficiency is propor t ional
to the c r o s s sect ion of that reac t ion . The efficiency of the c rys t a l can be
de termined if one nneasures coincidences between neutron pulses produced
m the Li l sc int i l la tor and pulses produced in another counter by gamma-
rays that accompany the neu t rons . As in other coincident counting, the
efficiency of the neutron detector is given by the ra t io of the coincidence
ra t e to the single counting r a t e for the g a m m a - r a y s . This efficiency is
a m e a s u r e of the des i red c r o s s sect ion.
It was proposed to use as a neutron source the neutron
group of low energy produced when protons of sufficient energy s t r ike a
thin l i thium ta rge t . These neutrons a r e accompanied by 430-kev gamma-
rays emit ted from the res idua l Be ' nuclei . If the exper iment is to be
feas ib le , one mus t be able to detect the 430-kev g a m m a - r a y s in the
p resence of any other rad ia t ion that might be p re sen t .
A sea rch for the 430-kev g a m m a - r a y s was made using
a sodium iodide g a m m a - r a y s p e c t r o m e t e r . The 430-kev g a m m a - r a y s could
not be reso lved from the 478-kev gannma-rays resul t ing from the inelast ic
sca t te r ing of protons from Li in the neutron sou rce . The intensity of
50
these la t te r g a m m a - r a y s was approximately four t imes that of the gamma-
rays accompanying the low energy neutron group. It was concluded that the
exper iment was not p rac t i ca l using l i thium as a neutron source . No further
work on this exper iment is being contemplated.
101-1 A Proposed Method for Measur ing Radiative Capture Cross Sections
Robert E . Holland and F . Paul Mooring Reported by F . Paul Mooring
To m e a s u r e radia t ive capture c ro s s sections by detecting the
capture g a m m a - r a y s , one must be able to identify and count the capture gamma-
rays in the p resence of other radiat ion. A method is proposed which should
allow one to do this in ce r t a in c a s e s .
A capturing m a t e r i a l is to be i l luminated by a well coUimated
beam of monoenerget ic neu t rons . The capturer is to be surrounded by a
counter consis t ing of la rge sodium iodide scint i l la tors giving as near as 4 'Z''
geometry as poss ib le . Fo r each capture p rocess a ce r t a in definite energy is
r e l ea sed which appears as a sequence of capture g a m m a - r a y s . These a r e
caught in the s c in t i l l a to r s , and the resu l tan t pulses a r e added. If the counter
were 100% efficient, a single pulse would resu l t which would be proport ional
to the energy r e l e a s e d in the capture p r o c e s s . Thus , by pulse-height ana lys i s ,
the capture g a m m a - r a y s should be easi ly selected from other gamma-producing
p r o c e s s e s originating in the captur ing ma te r i a l .
There a r e s eve ra l difficulties that one can expect to encounter
in this exper iment . The counter efficiency, part ly because of solid angle
51
51 effects, can not be made to be 100%. This will reduce the number of counts
in the capture peak; but if the counter efficiency is la rge enough, one should
sti l l be able to reso lve it.
A capturing m a t e r i a l , however , a lso acts as a neutron s c a t t e r e r .
Since iodine has a very l a rge capture c r o s s sec t ion , the re will always exist
a s t rong iodine capture peak cor responding to the iodine capture energy of
about 8 Mev. Fo r this r eason the method is applicable only to m a t e r i a l s
whose capture energy is dist inguishably different from that of iodine. Also
the low counting r a t e s to be expected forces one to use m a t e r i a l s with l a rge
capture c r o s s sec t ions . These two conditions mean that the method is bes t
suited for measu r ing the cap ture c r o s s sect ion of heavy isotopes .
Work is now in p r o g r e s s to t e s t the method. Ar rangements
have been made with Be rna rd H a m e r m e s h to bor row seventeen two-inch
cubes of sodium iodide for the counter . P lans for the set up have been
worked out, capture samples have been p r o c u r e d , e lec t ronic equipment is
under cons t ruc t ion , and var ious mechanical pa r t s a r e being made. It is
hoped to t ry the method in the near future.
102-1 Self Detection of Neutron Cross Sections (5211-01)
Alexander Langsdorf , Jr . J ames E. Monahan, William A. Reardon Reported by William A. Reardon
A group of samples including Au, Ag , Z r , S, P b , Ni , and
Al were col lected to pe r fo rm the exper iments r e f e r r e d to by Langsdorf in
ANL-4397 and ANL-4680.
52
A shor t run was made at 120° to find proper th icknesses and
to check on the observabi l i ty of se l f -detect ion effects.
A longer run at z e ro degrees covering neutron energies from
0. 1 to 1.0 Mev has been completed on Au, P b , Z r , S, and Ni. A 50-kev
t a rge t was used to insure effective averaging of the c r o s s section. The
analysis will be r epor t ed in the next repor t .
109-3 Neutron Diffraction Apparatus (5211-01)
Robert W. Holmes (Central Shops), Roy Ringo, Surain S. Sidhu (Metallurgy Division) Reported by Roy Ringo
The const ruct ion of this apparatus is near ly complete . The
pr inc ipa l work remaining is the instal la t ion at C P - 5 .
110-3 (Crys ta l Spec t rometer for 0. 1 to 100-ev Neutrons) (5211-01)
Sol Raboy and Roy Ringo Reported by Sol Raboy
Nothing was done on the c rys t a l spec t romete r for neutrons
during this qua r t e r . It is planned to move it to CP-5 in the next qua r t e r .
112-4 (The Neutron Spect rum of a Standard Ra-Be Photo Source) (5261-01)
Char les Eggler
Work on the se l f - t r igger ing cloud chamber is s t i l l delayed
because of intensive work on equipment for fast neutron spec t ra determinat ion.
53
S3 114-2 Development of a Recoil Type Neutron Spect rometer (5211-01)
Gilbert J. Per low
Work is continuing on the scheme descr ibed in the las t qua r t e r ly
r e p o r t , where in the recoi l in a propor t ional counter is coUimated by coincidence
with the sca t t e r ed neut ron , the l a t t e r ' s d i rec t ion being appropr ia te ly chosen.
In the p resen t a r r angemen t the propor t ional counter contains
deuteromethane. The detector for the sca t t e r ed neutrons is a Lucite slab
containing 7 B F3 c o u n t e r s , and it is placed to detect neutrons sca t t e red into
the backward hemisphe re . The delay between a sca t t e r ing event and the sub
sequent detection of the sca t t e r ed neutron is taken c a r e of by s t re tching the
recoi l pulse for 50 m i c r o s e c o n d s .
A t r i a l of the s y s t e m at p re sen t is awaiting the p repara t ion of
t r i t i um- f ree CD^, the CD^ on hand having been found somewhat excess ive ly
contaminated with CD3T.
115-2 Neutron Counters Containing Boron Tr imethyl (5211-01)
Alexander Langsdorf , J r . and William A. Reardon Reported by Alexander Langsdorf , J r .
Active work on counters of this type is in abeyance at the
l abora tory since it is being pursued actively at the Universi ty of Chicago.
No fur ther r e p o r t s will be made again until work on such counters is again
being done at the labora tory .
54
120-4 Cal ibra t ion of a Ra-Be Neutron Source (5211-01)
Willard C. Jordan
Using the technique descr ibed by Signnund P . Ha r r i s in previous
r epo r t s on this p ro jec t , six additional cal ibrat ion runs on Ra-Be neutron
source No. 312 have been made . (The resu l t s of the f i rs t th ree runs were
repor ted las t q u a r t e r . ) A var ie ty of counting equipment t r o u b l e s , some of
which may have been p resen t during the f i r s t three r u n s , cas t doubt on the
accuracy of the r e su l t s obtained to date. An average value for Q (the number
of neutrons emit ted per second) obtained from the resu l t s of aU runs is 5. 5
X 10 . In view of the sp read in the data it is believed that the probable e r r o r
is a t l e a s t 5%.
For a substant ia l reduction in this e r r o r , ref inements in the
counting technique will probably be n e c e s s a r y . The rep lacement of the
end-window Geiger counter with a gas flow counter or a thin anthracene
scint i l lat ion counter and the use of pulse-height d iscr iminat ion a re under
considerat ion.
One source of sys temat ic e r r o r is the detection of coincidences
betw^een knock-on Compton e lec t rons and their corresponding back - sca t t e r ed
photons. Discr iminat ion on both s ides of the coincidence c i rcui t against
low energy ( ^ 2 5 0 kev) radiat ions should el iminate this source of e r r o r
without s e r ious ly affecting the efficiency of the detectors for the Na rad ia t ions .
55
ss 131-4 Average Charge of Daughter Atoms After Nuclear Exci tat ion
(5211-01) Sol Wexler
The paper on this work is scheduled to appear in The Physica l
Review for January 1, 1954.
132-4 (Chemical Service Work) (5211-03)
Sol Wexler
No work in this field was per formed during this qua r t e r .
133-3 Design Study of a Mult i-Bev P ro ton Synchroton (5211-01)
John J. Livingood and Morton H a m e r m e s h Reported by John J. Livingood
Lec tu res on the fundamental pr inc ip les of magnetic a c c e l e r a t o r s
have s t a r t e d , with an init ial enro l lment of sixty from the var ious divisions of
the Labora to ry . It is ant icipated that four to s ix sess ions will be adequate
to cover the conventional types . Afterwards attention will be d i rec ted to the
a l ternat ing gradient v a r i e t y , with ea r ly emphas is on the theory involving
l inear equat ions , as it s eems impor tant that this be thoroughly understood
before embarking on the non- l inear poss ib i l i t i es .
134-3 Optical Exci ta t ion Spectra of He^ Species After p" Decay of T2
M a r k s . F r e d (Chemis t ry Division), F r e d T. P o r t e r (Chemist ry Division), Sol Wexler Reported by Sol Wexler
In the previous quar t e r ly r epo r t were l i s ted fourteen " l ines"
in the u l t ra -v io le t and visible radia t ion found in the s p e c t r u m of t r i t i um gas
at high p r e s s u r e . Search of tables of wavelengths of atomic and molecular
56
^6 spec t ra has now made poss ib le the probable ass ignment of most of the l ines
to ce r t a in e lectronic t rans i t ions as follows:
Line
3914 A
4087
4165
4277
4305
4339
4433
4500
4643
4707
4853
5009
5300
5610
Table IV
Probable electronic t rans i t ion
N2+ (0,0 transit ion)
H
N2+ (3,4)
N2+ (0,1)
H. a
N2+ (4,6)
N2+ (1,3)
N2+ (0,2)
N2+ (3,6)
Since the seven N2 " l ines" show a band head s t ruc tu re and
their wave lengths agree within exper imenta l var ia t ion with known ni trogen
bands , they a r e probably m e m b e r s of the negative band spec t rum of N2 ,
which has been observed previously when t r a c e s of N2 a r e p resen t in He
excited by var ious ionizing d i scha rges . In our experiment the initially
57
S7 excited hel ium may be produced by b e t a - r a y s emit ted in the gas volume and/or
3 excited He species resul t ing from the beta t rans i t ion in t r i t ium. The excitation
is t r a n s f e r r e d to a n i t rogen molecule by coll is ion; the ionized, excited N2^ then
r ad i a t e s . Since ni t rogen was undoubtedly p resen t in low concentra t ion in our
expe r imen t s , the expected He spec t rum was probably masked by these coll isions
of the second kind.
The th ree t r i t i um atomic l ines l i s ted in the table a r e probably
due to d issoc ia t ion , by beta p a r t i c l e s , of T2 into excited t r i t i um a toms . Four
of the observed lines a r e as yet unidentified.
Since s t r ingent precaut ions a r e n e c e s s a r y to exclude t r ace s of
n i t rogen, a new appara tus is being planned.
135-3 E lec t ron -Neu t ron Interact ion (5211-01)
Roy Ringo
Our m e a s u r e m e n t of the e lec t ron-neu t ron in teract ion by the
a s y m m e t r y of the neutron sca t te r ing by the noble gases depends on the coherent
neutron sca t te r ing ampli tudes of these gases .
P r e l i m i n a r y work on the m e a s u r e m e n t of these coherent
ampli tudes is now under way. A sys t em has been built with which it is hoped
to produce krypton and xenon powders of c rys t a l s of appreciable s ize and
random orientat ion.
In the next qua r t e r this will be tes ted by x - r a y diffraction.
58
If success fu l , this sys t em will be used to produce powders for neutron
diffraction m e a s u r e m e n t s from which the des i red sca t te r ing amplitudes
can be obtained.
£1 II. MASS SPECTROSCOPY
1-4 Mass Spec t romet r i c Techniques (5211-08)
David C. Hess and Mark G. Inghram Reported by David C. Hess
An invest igat ion was c a r r i e d out to check the feasibili ty of
examining copper by means of the " t r ip le f i lament" ion source . This
subject was made of immedia te in te res t by the necess i ty of detecting very
smal l amounts ( less than one ppm) of copper in germanium. Our expe r i -
inents showed that no rmal copper can be m e a s u r e d in the amount probably
available (25 m i c r o g r a m s per sample) and use of the isotopic dilution
technique is poss ib le . Fu r the r work will probably be done by W. H. Johnston
at P u r d u e , whose in t e re s t caused us to make the c u r r e n t t e s t s .
2-4 Const ruct ion of MA-17 (5211-08)
Henry E. Stanton
Ear ly in this qua r t e r it became apparent that the hydrocarbon
background in MA-17 was excess ive for any p r e c i s e exper imenta t ion . The
m a s s spec t rome te r was accordingly shut down for a thorough cleaning.
In addition, a new^ source c losure has been completed in the
shop, and a separa te source pumping sys t em is being instal led. This will
p e r m i t re la t ively high p r e s s u r e s in the source while maintaining the lowest
poss ible p r e s s u r e s in the e lec t ros ta t i c deflecting sy s t em amd spec t rome te r
tube. This la t te r is e ssen t i a l to reduce gas sca t te r ing of the ion beam
60
which may have only a few hundred volts energy.
During the next qua r t e r the cleaning and remodeling p r o c e s s
should be completed and studies of the chemica l p roper t i e s of carbon
r e s u m e d .
10-4 A Search for Rare Natural ly Occurr ing Isotopes (5211-08)
David C. Hess and Mark G. Inghram Reported by David C. Hess
Since MA-16 is not yet in operating condition, only one element
has been examined. Aluminum-26 is not p resen t with an abundance of
g r ea t e r than one pa r t in 2 ,000 ,000 of Aluminum-27. This was m e a s u r e d
on MA-15, and a lower l imit is expected when MA-16 is applied to the problem.
11-4 Technet ium in Nature (5211-08)
Mark G. Inghram
The resu l t s given in r epor t I I -11-2 , (ANL-5080), were
r epor t ed to the Nuclear Geophysics Conference at Yerkes Observatory
in September and will appear in the proceedings of the conference.
12-4 (Double Beta Disintegrat ion of Te^"^^) (5211-08)
Richard J. Hayden and Mark G. Inghram Reported by Richard J. Hayden
No p r o g r e s s has been made on this problem this qua r t e r .
61
30-4 The Heat of Vaporizat ion of Carbon (5211-08)
Mark G. Inghram
P r e l i m i n a r y tes t ing of the Knudsen furnace has begun but
no repor tab le r e su l t s have been obtained to date.
(The previous r epo r t on this p r o g r a m was included by mis take
in the c lass i f ied supplement ANL-5141 , r a the r than in the unclassif ied
r epo r t ANL-5140, where it should have appeared . )
31-4 (Studies of E lec t ron Impact) (5211-08)
William A. Chupka
There a re no r e su l t s to r e po r t at this t ime .
33-4 (Molecular States in Rare Gases) (5211-08)
David C. Hess and Mark G. Inghram Reported by David C. Hess
Nothing has been done which was exclusively concerned with
this project .
34-4 Argon Age Determinat ions (5211-08)
Gerald Wasse rburg (Universi ty of Chicago) and Richard J. Hayden Reported by Richard J, Hayden
After another s e r i e s of vacuum and e lec t ronic diff icult ies,
MA-18 was again put in operat ing o rde r . The rock samples which were
obtained from the Universi ty of Toronto were p r o c e s s e d and analyzed. Our
r e su l t s a r e in agreement with the old value for the K branching ra t io of
»
62
d2
0 .13 . They cannot be in te rp re ted to agree with the value of 0. 06. Details
have been submit ted in a le t te r to the editor of the Physical Review.
63
1,3 III. CRYSTALLOGRAPHY
1-4 (Crystal Studies of Technet ium Compounds) (5211-11)
William H. Zacha r i a sen
No further p r o g r e s s has been made during the past qua r t e r .
2-4 (Structural Studies of Boric Acids) (5211-11)
H. Anne Ple t t inger
No further p r o g r e s s has been made during the pas t qua r t e r ,
20-2 ( Table of Squared Sines) (5211-11)
H. Anne Ple t t inger
No further p r o g r e s s has been made during the pas t qua r t e r .
64
V. THEORETICAL PHYSICS, GENERAL
1-4 In terpre ta t ion of the Energy States of Light Nuclei (5211-07)
David R. Inglis
The application of the droplet model of nuclei to dynamical
p r o b l e m s , while empir ica l ly quite successfu l , has not seemed ent i re ly
sa t i s fac tory because of the ad hoc nature of the assumption that nuclear
m a t t e r behaves like a c l a s s i ca l i r ro ta t iona l fluid. The collective kinetic
energy of a nucleus in the act of being deformed may be descr ibed quantum
mechanical ly by means of deformations of the cen t ra l model with osci l la tor
wave functions in the adiabatic approximation. This equivalent kinetic
ene rgy , depending on the square of the ra te of change of the deformation
p a r a m e t e r or on the square of the angular velocity of a rotating deformation,
a r i s e s from the t empora ry and par t i a l excitation of higher osci l la tor s ta tes
in the non-s ta t ionary p rob lem. The adiabatic approximation is found not
to be valid for an osci l lat ion between prolate and oblate shapes of a c losed-
shel l nucleus (such as might desc r ibe the f i r s t excited state of O ) , but
IS valid and useful in descr ib ing the low rotat ional s ta tes of all but the light
nuclei .
2-4 Energy States of Light Nuclei (5211-07)
Dieter Kurath
The contr ibut ions of all Ip shell configurations to the ground
s ta te wave function were calcula ted for the s imple case of mass number
is A = 14 and a lso for A = 13. It is found that the per tu rba t ion p rocedures use
previously a r e inadequate and that diagonalization of the in teract ion m a t r i x
must be c a r r i e d out. T h i s , then , becomes an in te rmedia te coupling ca lcu
lation.
The resu l t ing magnet ic moments r ema in quite c lose to the
values given by the s imple j j -g round conf igurat ions , although other s ta tes
a r e mixed into the ground state wave function to a cons iderable extent.
The necess i ty for including higher excitat ion j j -wave functions is indicated
by the r e su l t s for C , where the zero o rde r j j -ground state (IP3/2) (•^Pl/2
gives /*•= 0 .64 . Mixing in only (lp,y2) ( l P l / 2 ' gives >*= 0. 02; but 6 3 5 4
including (Ip3/2) ( lPi /2) and (Ip^^^) (lPj/2^ as well gives / /= 0. 72.
Experinaentally yM.= 0.70.
The s ta tes which mix in most s t rongly with (Ip- ,_) (Ip, ,^)
a r e those f rom (Ip, ,^) (Ip, , , ) . If these a r e found to be the major
cont r ibu tors to the level spacing of C as wel l , one may hope to have a
p rocedure for approximating fea tures of the m o r e complicated s t r u c t u r e s
a t A = 10, 1 1 , and 12, pa r t i cu la r ly the low magnetic moment of B-*̂ .
4-4 (Investigation of Nuclear Structure) (5211-07)
5-4 (Book on Nuclear Shell Structure)
Mar ia G. Mayer
Dr. Mayer being on extended l eave , the re is no r epo r t to
be made on these p r o g r a m s .
66
7-4 Collective Descr ip t ion of Nucleon Interact ions (5211-07)
Melvin F e r e n t z
In col laborat ion with David Pines (University of Illinois)
and Mur ray Gell-Mann (Universi ty of Chicago) work on the quantum
mechanica l re formula t ion of the collect ive descr ip t ion has been continued.
In the l a s t qua r t e r the f o r m a l i s m has been general ized by being expressed
in t e r m s of any complete se t of solutions of the equation
[V^ + k^J F (F) = 0
satisfying boundary conditions such that any a r b i t r a r y constant is a solution.
The choice of base functions na tura l to a spher ica l ly syminet r ic nucleon-
nucleon in terac t ion is the se t consis t ing of products of spher ica l harmonics
and spher ica l Besse l functions. The only allowable boundary condition is that
a t some a r b i t r a r y dis tance f rom the center of the nucleus the derivat ive
of the function in the rad ia l d i rec t ion must vanish. This boundary condition
is all that is needed to de te rmine the nature of the collective osci l lat ion
l e v e l s , both as to wave number and angular momentum, in t e r m s of the
in te r -nuc leon potential and the boundary condition r ad ius . The lowest
l eve l , which fits quite well the photonuclear r e s o n a n c e , is shown to be
pure dipole as had been conjectured for the resonance level by Goldhaber
and Te l l e r .
M. Goldhaber and E. T e l l e r , Phys . Rev. 74, 1046(1948).
67
hi 8-4 Monoenergetic Neutrons from Charged Pa r t i c l e Reactions
William A. Reardon
This projec t is now esent ia l ly complete as it per ta ins to the
7 7
Li (p ,n ) Be reac t ion . The calculat ions a r e complete and a re being l i s ted
in tabular form by the computer group. A set of graphs for ze ro angle has
been p r e p a r e d for the use of the Van de Graaff group and may be reproduced
for any other i n t e r e s t ed p e r s o n s . The graphs cover the proton energy
range f rom 1. 882 Mev to 3. 560 Mev (or neutron energy from . 030 to
1.875 Mev).
This graph will be extended to proton energ ies up to 5 Mev
and neutron energ ies to 3. 4 Mev.
Considera t ion is being given to per forming a s imi l a r ca lcu-3 3
lat ion for the H (p,n) He react ion.
9-2 Nuclear C r o s s Sections by the Clouded Crys t a l BaU F o r m a l i s m
(5211-07) B e r n a r d I. Spinrad
The data available on the c r o s s sect ions of heavy e lements
against which a theory can be checked a r e quite s c a r c e ; compilat ion of
data on total and reac t ion c r o s s sect ions is continuing.
To form a self-consis tent theory including as many data as
p o s s i b l e , the p a r a m e t e r s used by Weisskopf a r e not appl icable . In
p a r t i c u l a r , the depth of the potential well has no a p r i o r i just if ication.
P r e l i m i n a r y computat ions a r e being nnade with potential wells whose depth
68
gives the p roper location for the ground state of the compound nucleus.
These wells a r e r a the r shal low, and a l a rge r imaginary component than
used by Weisskopf and P o r t e r is r equ i red .
Formula t ion of the p rob lem for eas ie r computation is being
invest igated,
28-3 Angular Dis t r ibut ion of Elas t ica l ly Scat tered Neutrons (5211-07)
Morton H a m e r m e s h
Explici t formulas have been obtained for the angular d i s t r i
butions of neutrons s ca t t e r ed near r e s o n a n c e , for t a rge t nuclei of spin 1/2,
1, 3 / 2 , and orbi ta l angular momentum up to C = 3. They a r e needed in the
planning and analys is of exper imenta l s tudies to be made with the Van de Graaff
genera to r . The formulas a r e too voluminous to give in detail h e r e .
29-3 Internal Convers ion in the L and M Sub-Shells (5211-07)
Eugene L. Church , Roland F , Herbs t , J ames E. Monahan Reported by Eugene L. Church
1. Introduction
Internal convers ion is the mos t important mode of de-exci ta t ion
of the excited s ta tes of heavy nuclei . The elucidation of the level schemes
of such nuclei depends on an unders tanding of the convers ion p rope r t i e s of
low-energy t rans i t ions in the L and M she l l s . P re sen t ly available exact
calculat ions a r e inadequate for this purpose . An at tempt is being m a d e ,
t h e r e f o r e , to extrapolate these r e su l t s by means of a c r i t i ca l examination
of appropriate non-relativistic approximations which are amenable to
numerical computation. Emphasis is being placed on the relative conversion
in the various sub-shells, which may be less sensitive to the approximations
employed than the corresponding absolute conversion coefficients.
2. Threshold Values of K-Shell Internal-Conversion Coefficients
To assess the effects of relativistic corrections in the calculation
of internal-conversion coefficients (ICC's) at low energies, absolute non-
relativistic K-shell coefficients have been computed at threshold for com
parison with the analogous relativistic results of Spinrad and Keller.
The threshold value of the K-shell ICC for E^radiation is given
by
„̂ -̂ -i 16 TT 274.^'^•'•^ J' r ^{2; 2^+2; -2) -j^
K 137 ^ Z J^^n" ^ J'. (2j+ 1) -^
where ^ is the relevant confluent hypergeometric function, and by
^ ( / - I ) I'' (2^+1)
for M^ radiation.
The above formulas have been used in the computation of
Table V. *
^ B. I. Spinrad and L. B. Keller, Phys. Rev. 84, 1056(1951).
^ M. H. Hebb and G. E. Uhlenbeck, Physic a 5̂ , 605 (1938).
^ S. D. Drell, Phys. Rev. 75, 132 (1949).
The numbers in parentheses are the powers of ten by which the entries should be multiplied.
70
^0
z
10
20
40
60
80
100
Z
10
20
40
60
80
100
T h r e s h o l d Valu^
1 .895 (+3)
1.185 (+2)
7 . 4 0 4 (0)
1 .463 (0)
4 . 6 2 7 (-1)
1 .895 (-1)
PK
1,837 (+2)
4 , 5 9 2 (+1)
1. 148 ( + 1)
5, 102 (0)
2 . 8 7 0 (0)
1 .837 (0)
es of K
^L^>
T a b l e V
-She l l I n t e r n a l - C o n v e r s i o n Coe
3 . 0 7 9 (+5)
4 , 8 1 1
7 , 5 1 7
6 , 6 0 0
1. 175
(+3)
( + 1)
(0)
(0)
3 , 0 7 9 (-1)
p'^'
1,242
7 . 7 6 1
4 . 851
9 . 5 8 2
3 . 032
1. 242
(+5)
(+3)
(+2)
( + 1)
(+1)
(+1)
^K
1.975 (+7)
7. 713
3. 013
1. 176
1. 177
(+4)
(+2)
(+1)
(0)
1 .975 (-1)
PL '̂ 2. 221
3 . 4 7 0
5 . 4 2 2
4. 760
8 . 4 7 3
2. 221
(+7)
(+5)
(+3)
(+2)
(+1)
(+1)
(4) ^K
7. 137 (+8)
6 .970 (+5)
6 . 8 0 7
1. 180
6 , 6 4 7
7, 137
PK
1.802
7. 040
2. 750
1. 073
1. 074
(+2)
(+1)
(-1)
(-2)
(+9)
(+6)
(+4)
(+3)
(+2)
1. 802 ( + 1)
iff icients
(5)
1,684 (+10)
4. 112 (+6)
1. 004 (+3)
7 . 7 3 8 (0)
2 . 4 5 1 (-1)
1. 684 (-2)
^ '^ '
8. 307 ( + 10)
8. 113 (+7)
7 . 9 2 3 (+4)
1. 374 (+3)
7 . 7 3 7 (+1)
8 . 3 0 7 (0)
The v a l u e s l i s t e d in T a b l e V differ f r o m the r e s u l t s of
S p i n r a d and K e l l e r by f a c t o r s of l e s s t h a n /v 4 o v e r the e n t i r e r a n g e of Z
c o n s i d e r e d . T h i s d i s c r e p a n c y m a y be due to a known c o m p u t a t i o n a l e r r o r
of t h i s m a g n i t u d e in the l a t t e r p a p e r , s o t h a t no d e t a i l e d c o m p a r i s o n c a n
be m a d e .
B . I. S p i n r a d , p r i v a t e c o m m u n i c a t i o n ( N o v e m b e r , 1 9 5 3 ) .
71
7/ The effects of sc reen ing have been neglected in all c a s e s .
One such effect is the lowering of the exper imenta l K-shel l binding energy^
2 2 re la t ive to the cor responding hydrogenic value of 1 (Z/137) mc . The 2
magnitude of this d i f ference, r ep resen t ing the posit ive e lec t ron kinetic
energy for which the r e su l t s in Table V a re appl icable , is shown in Table VI.
Table VI
Z
T
10
0 .49
20
1. 40
40
3, 77
60
5 . 4 1
80
3 .99
100
< 0
3. Threshold Convers ion in the L and M Sub-Shells
Extending the work previously repor ted to al l e lec t r ic
t rans i t ions of p rac t i ca l i n t e r e s t , re la t ive L and M sub-she l l ICC's have
been computed at the i r respec t ive thresholds in the non- re la t iv i s t i c l imi t .
Although the express ions obtained a r e s t r i c t ly valid only for Z ^fC 137
and vanishing e lec t ron m o m e n t u m , the re la t ive convers ion in the var ious
sub-she l l s may be indicative of the si tuat ion in c a s e s of m o r e physica l
i n t e r e s t . This has been verif ied by explicit calculat ion in the case of the
L shel l . "̂
The r e su l t s obtained a r e s u m m a r i z e d in Tables VII and VIII,
where the intensity of the nnost s trongly conver ted sub-she l l has been taken
as unity.
5 Hi l l , Church , and Mihelich, Rev. Sci. Ins t r . 23^, 523 (1952),
6 A N L - 5 0 8 0 , p, 92.
'^ANL-5141, p . 6,
72
7^ T a b l e VII
R e l a t i v e T h r e s h o l d I n t e r n a l C o n v e r s i o n in the L S u b - S h e l l s
T r a n s i t i o n
1 s = LI 1
P = L n + L j i i
E l
1 0. 364
1
E2
0. 002
1
E 3
0. 003
1
E4
0. 001
1
E 5
8 X 10"^
1
T a b l e VIII
R e l a t i v e T h r e s h o l d I n t e r n a l C o n v e r s i o n in the M Sub-She l l s
T r a n s i t i o n
S = M I
P = M i i + M j j J
D = M j y + M y
E l
0. 278
1 0. 864
1
E2 i
0. 001
1
0 . 0 3 6
E 3
_4 2x10 ^
1
0 . 4 5 6
E4
4x10"'^
0. 168
1
E5
- 6 3x10
0. 031
1 1
The r e s u l t s o b t a i n e d for t h e L s h e l l a r e in q u a l i t a t i v e a g r e e
m e n t w i th the r e l a t i v i s t i c u n s c r e e n e d c a l c u l a t i o n s of G e l l m a n et a l ,
9 and the e m p i r i c a l c l a s s i f i c a t i o n of M i h e l i c h . In the s e v e r a l c a s e s
i den t i f i ed thus f a r , the above p r e d i c t i o n s a r e a l s o in a c c o r d wi th e x p e r i
m e n t a l r e s u l t s for e x t r e m e l y h e a v y e l e m e n t s in bo th the L and M s h e l l s .
E x t e n s i o n of the above c a l c u l a t i o n s to m a g n e t i c m u l t i p o l e s
i s u n d e r c o n s i d e r a t i o n .
An a b s t r a c t of the above r e s u l t s h a s b e e n s u b m i t t e d for
p r e s e n t a t i o n a t t he New Y o r k m e e t i n g of the A m e r i c a n P h y s i c a l Soc ie ty
in J a n u a r y , 1954,
8 G e l l m a n , G r i f f i t h , and S t a n l e y , P h y s . Rev . 8 5 , 944 (1952). 9 J . W. M i h e l i c h , P h y s . Rev . _87, 646 (1952).
10 A N L - 5 0 8 1 , p . 7,
73
73 30-4 (Consultation on Miscel laneous Theore t ica l Problems) (5211-07,
5211-14) Morton H a m e r m e s h
No further p r o g r e s s has been made on this pro jec t during the
past q u a r t e r .
31-4 (Configuration In terac t ion in I ron Group Elements ) (5211-14)
Jean F . Hall and Norber t Rosenzweig Reported by Norber t Rosenzweig
Work on this pro jec t will be r e s u m e d when the AVIDAC becomes
available for computa t ions .
32-4 P l u r a l Scat ter ing of E lec t rons at Oblique Incidence (5211-14)
Morton H a m e r m e s h and James E. Monahan Reported by James E. Monahan
A paper on this subject is scheduled to appear in the March 1
i ssue of the Phys ica l Review.
34-4 Quantized Space Time (5211-14)
Emi l J. Hellund and Katsumi Tanaka Reported by Katsumi Tanaka
A majiuscript entit led "Quantized Space T i m e " has been
accepted for publication in the Physica l Review, This contained the
formulat ion of the ope ra to r s and commuta to r s of the space t ime o p e r a t o r s ,
the de terminat ion of the eigenfunctions and eigenvalues of the space t ime
o p e r a t o r s , and the t ime spec t rum of the plane wave solutions of the Dirac
equation. F ina l ly , for the solution of the p rob lem of par t i c le coupled to
74
field, a convergent pe r tu rba t ion analys is is proposed by means of a unitary
t r ans fo rma t ion m a t r i x >vhich is n e c e s s a r y to obtain t ime local izable solutions
of the Dirac equation,
A note on the method of obtaining t ime localized wave functions
is being p r epa red and expected to be submitted. This method follows from
a var ia t ional pr inc ip le .
Application of this method is undertaken.
37-3 On the Relation of the Schrodinger and Boltzmann Equation (5211-14)
Emi l J. Hellund and Katsumi Tanaka Reported by Katsumi Tanaka
In a paper by Hellund and Brachman that is to appear in
the Phys ica l Review, it was demons t ra ted that the Schrodinger equation
caJi be t r ans fo rmed into a continuity equation of the Boltzmann type , l e ss
the col l is ion t e r m , thus formulat ing quantum mechanics in such a way
as to make explicit use of the concept of t r a j ec to r i e s .
This is being genera l ized in the following manner to include
the col l i s ion t e r m and thus complete the cor respondence . We se t up the
analogue of the col l is ion t e r m in the new rep resen ta t ion , t r ans fe r back
to the Schrodinger r ep resen ta t ion and get the usual form of the Schrodinger
equation.
38-2 Cerenkov Radiation (5211-14) Katsumi Tanaka
Resea rch was t e rmina ted las t qua r t e r . The submitted paper
IS scheduled to appear in the F e b r u a r y 1 issue of the Physica l Review,
75
7s5 39-2 Applications of the Theory of Angular Cor re la t ion (5211-07)
Melvin Fe ren t z and Norber t Rosenzweig Reported by Norber t Rosenzweig
In connection with the exper imenta l work of S. Raboy and
V. E. Krohn we have calculated some y-Y angular co r r e l a t i on functions
which a r e per t inent to the study of Pb , and we give he re the r e su l t s
which w e r e obtained.
Let j j j and j ^ be the in i t ia l , in te rmedia te and final angular
momenta of the decaying nucleus . The t rans i t ion betAveen j , and j is a s s u m e d
^ £ ' 2
to be a mixture of 2 ^ and 2 / mul t ipo les . Let S ( ^ is real) denote the
intensi ty ra t io of 2 ' to 2 / pole radia t ion. The t rans i t ion between j and jo
is a s sumed to be pure 2 '*pole radiat ion. The cascade is abbrevia ted as
ji kJ,^,y j ( ^ J2.
The angular co r r e l a t i on function has the form^
W (0) = : ^ A ^ P) (cos 0) + 2 / J : B ^ P .^ (cos 0) + S ^ X C ^ P ^
(cos 0) AQ = C^ = 1 B^ = 0
The coefficients A ^ , BJ , and Q^ a r e products of Clebsch-Gordan
and Racah coefficients with the angular momenta as the i r arguments .
The coefficients for the five cascades which we have t r ea t ed to date a r e
given in the adjoining tab le , which has been p r e p a r e d with the a s s i s t ance of
L . C. Renick.
1 C. F . Sunyar , e t a l , Phys . Rev. 79, 181 (1950). H. F rauenfe lde r , to be published in Phys . Rev. Helpful cor respondence with Dr. Frauenfe lder is great ly acknowledged.
2 L. C. Biedenharn and M. E . R o s e , Rev. Mod. P h y s . 25 , 729 (1953).
76
1^ Coef f i c i en t s in W (0)
7(56)2(2)0
. 2472
- . 02931
6(45)2(2)0
. 2208
- . 01798
9(67)3(3)0 8(56)3(3)0 8(67)2(2)0
. 4 6 4 3 . 4 3 2 7 . 2 6 5 3
01833 0140
4 0 - 2 C o m p t o n S c a t t e r i n g
K a t s u m i T a n a k a
(5211-14)
- . 0 3 8 4
^6
Bz
B4
B
Cz
C4
C6
—
-. 1674
.08931
-
-.2653
. 2177
-
-
-. 1974
.09106
-
-.2720
. 1758
-
-.003518
-.2187
-.03508
.02155
-. 2087
-.08220
.04948
-. 0015
-. 2537
-.03694
.01847
-. 2321
-.07334
.03342
—
-.1452
.08540
-
-.2585
.2485
-
The content of the previous r epor t will appear in P ro fessor
J. M. Jauch ' s forthcoming book on Quantum E lec t rodynamics , thus
t e rmina t ing the project . J. M. Cook has a p r o g r a m for the AVIDAC
which will verify these ca lcula t ions .
41-1 Solutions of the Dirac Equation for a F r e e Pa r t i c l e (5211-14)
Emi l J. Hellund and Katsumi Tanaka Reported by Katsumi Tanaka
Various authors have thoroughly d iscussed the motion of free
77
77 par t i c l e s obeying the Dirac equation. Stat ionary solutions of the Dirac
equation form the bas i s of any re la t iv i s t ic t r e a tmen t of fe rmions . . In the
absence of any coupling with other f ie lds , the solutions of the free par t i c le
type govern the motion of the pa r t i c l e . Textbooks d i s c u s s , usually in some
de ta i l , the re la t ive ly s imple case of plane wave solut ions. It is the purpose
of the p r e s e n t note to point out that for the general case the der ivat ion of
solutions is equally s imple . This is accompl ished by re tent ion of the complete
fac tor iza t ion of the Klein-Gordon ope ra to r . The reso lv ing point is the
s imple observat ion that , in the absence of any external f ie lds , the a lgebra
of the momentum ope ra to r s is identical with that of their e igenvalues .
Hence , for example , to a plane wave solution of f o r m .
e ' ( ^ - - t - E t ) (1)
where V = c = 1 the re can be wr i t ten the cor responding genera l (2)
solut ion, cp,
i d/dt + m
• 1 d/^yi +B/3V
1 C. G. Darwin , P r o c . of the Royal Society A 118, 654, (1928). E. L. Hill and R. Landshoff, Rev. Mod. Phys . ^0.^ (1938). W. Paul i and H. Bethe , Handbuch Der Physik 24, 1 (1943).
78
where F sat isf ies the Klein-Gordon equation,
( a / i y " ^ + 3 y ^ / * + .^y^^2-=^ - m ^ ) F = ^ ^ F / a t ^ (4)
As an example , a spher ica l wave with a s ingulari ty on the light
? 7 7 cone r = c t is der ived by sett ing F equal to
F = K, AmVr^ - «^ t̂ ) ] I t J (5)
where Ki is the Besse l function of the second kind, with a s ingulari ty for
a null a rgumen t , and going exponentially to ze ro for infinite a rgument .
The behavior of fermions in an enclosure thus is reduced to
the cor responding acous t ica l p rob lem.
A paper will be subnnitted for publication in the Physica l Review.
77 VI. REACTOR THEORY ' T . - I l l I I •
7-1 Lec tu re s on Neutron T r a n s p o r t Theory (4520-01)
B e r n a r d I. Spinrad
A cou r se on this subject is being p resen ted . L e c t u r e s so far
have included the genera l in t roductory m a t e r i a l and an exposition of var ious
techniques for deriving the diffusion approximat ion. Unclassified notes
a r e being i ssued concurrent ly with the l e c t u r e s , and from t ime to t ime
more carefvilly r ev i sed notes will be i s sued . It is hoped by this means to
pa r t i a l ly fill the gap in the l i t e r a t u r e which exis ts between the e l emen ta ry
exposi tory texts and the advanced monographs on this subject and to
p re sen t the topic of t r anspor t theory in such a way as to be pa r t i cu l a r ly
useful in r eac to r ca lcula t ions .
80
VII. ELECTRONIC DIGITAL COMPUTERS
0-2 Report on the Digital Computer Symposium (4520-02)
J. C. Chu
Manuscr ip ts for twenty-one of the twenty- three papers
p re sen ted during the sympos ium in August have been rece ived and will be
included in the Proceed ings of the Symposium to be published as an ANL
repo r t ,
1-4 (Report on the Design of the AVIDAC) (4520-02)
Raymond F . K r a m e r
No further p r o g r e s s has been made on prepara t ion of this
r e p o r t .
2-4 Improvements of the AVIDAC (4520-02)
Car l J. B e r g s t r o m , J. C. Chu, David H. Jacobsohn, Raymond F . K r a m e r Reported by Car l J. B e r g s t r o m
Elec t ronic Commutator
The new commuta tor has been bench tes ted and instal led in the
a r i thmet ic unit of the AVIDAC. Changes and instal lat ions in the console
due to this have been a l so completed. No test ing of the new units since
ins ta l la t ion has been done.
R e a d e r , Punch, and Re -pe r fo ra to r
The F e r r a n t i r e a d e r has not as yet been rece ived from the
manufac tu re r .
81
The fast punch mechan i sm is at p r e sen t under const ruct ion
and will be instal led as soon as shop work is completed.
A r e - p e r f o r a t o r is being bui l t , using pa r t s obtained from the
or iginal punch and r e a d e r .
Power Supply Revisions
It became apparent during machine operat ion that c e r t a in
vol tages obtained from taps on the ba t t e ry supply s y s t e m were varying to
an excess ive degree . As the loads p re sen ted by the machine under operat ing
conditions v a r y , no p roper equalizat ion which would c o r r e c t this drift was
poss ib le . The re fo re , it was decided that as many of these voltages as
poss ib le should be der ived instead f rom regula ted s o u r c e s . Changes were
made in the r egu la to r s to allow this to be done and two new regu la to r s were
added to complete the requ i red l i s t . These changes a r e complete but to
date have not been tes ted over any but very shor t i n t e rva l s .
Control
Several c i r cu i t s in connection with the control sect ion of the
AVIDAC were modified in such manner as to improve the safety and
re l iabi l i ty of operat ion. These changes were made in accordance with
knowledge gained from machine breakdowns a n d / o r re -eva lua t ion of
s tandards m locations where fai lure might possibly occur .
Logical changes were a lso made n e c e s s a r y by the instal la t ion
of the new input-output equipment and assoc ia ted o r d e r s . These changes
have been made but have not yet been tes ted .
82
3-4 Operat ion and Maintenance of the AVIDAC (4520-02)
Ca r l J. B e r g s t r o m , J. C, Chu, David H. Jacobsohn, Raymond F . K r a m e r
Reported by David H. Jacobsohn
Cathode Ray Tube Selection
A second batch of one hundred Dumont 5CPIA's was obtained.
At p r e s e n t , one- th i rd of these tubes has been tes ted. Of the tubes t e s t ed ,
two- th i rds passed the tes t of 256 read-a rounds or be t t e r . One-half
of the tubes pass ing the r ead -a round tes t were impuri ty f ree . Some at tempt
will be made to r ecover the remain ing tubes by sparking. These resu l t s a r e
s imi l a r to those obtained on the f i r s t batch of Dumont tubes previously
r epor t ed .
Modifications were made in the memory tes t rack to facilitate
automatic impur i ty detection.
Schematic Drawings
An ove r - a l l p r in t rev is ion project was made to bring all
control pr in ts into a s t andard form and up to da te , in order to facili tate
e a s i e r serv ic ing and unders tanding of the control .
4-4 (Test Routines for the AVIDAC) (4520-02)
Jean F . Hall
No new rout ines were added this qua r t e r .
83
TJ 5-4 Sub-Routine L i b r a r y for the AVIDAC (4520-02)
J ames Alexander , Jean F . Hal l , Robert H. McDowell Reported by Jean F . Hall
One new routine was machine tes ted this qua r t e r . It is
S - 1 1 . 1 , t r apezo ida l in tegrat ion.
6-4 (Coding Manual for the AVIDAC) (4520-02)
James Alexander , Donald A. F l a n d e r s , Jean F . Hall Reported by Donald A. F l ande r s
No work has been done since the previous r epo r t .
7-4 The Auxil iary Memory for the AVIDAC and ORACLE (4520-02)
Raymond F . K r a m e r and Les l ie C. Mer r i l l Reported by Les l i e C. M e r r i l l
Recording head production is well under way. Many, if not a l l ,
of the ten heads should be finished in the next quarter .
The re su l t s of l i fe - tes t s on a prototype head as sembly indicate
that a life of 2,000 running hours can be expected between overhauls . The
head bodies will have to be rebui l t after four ove rhau l s , while the center
p ieces should be good for twenty overhauls . The lifetime of the record ing
5 tape running on the head only is on the o rde r of 10 p a s s e s .
Modification in the design of the tape driving units a r e
complete . Product ion of the dr ive units has s t a r t ed . It is ant icipated that
they will be finished in the coming qua r t e r . Tes t s of a prototype dr ive
indicate that the units themse lves have an indefinite l i f e , while the tape
84
S'f can be expected to take 2,000 clutching operations at any point before fa i lure .
The main f rames of the auxi l iary m e m o r i e s a re about 50%
complete .
A prototype wind-up r e e l and basket tape s torage mechanism is
nea r ly finished. After tes ts and possible changes , the entire se t of s torage
units will be cons t ruc ted and placed on the main f r ames . No great difficulty is
anticipated since the s torage units a r e very s imple m design and operation,
A sample and drawings of the basic electronic reading-wri t ing
chas s i s have been completed in order that bids for the construct ion of 80 such
units may be sent out. The sample passed all acceptance t e s t s .
Design of the e lec t ronic clutch driving units has been com
pleted. A model of the unit must be built and tes ted.
No work was done on power supplies or control for the
auxi l iary m e m o r i e s .
8-4 (A P r o b l e m in Par t i t ions) (5211-14)
Donald A. F lande r s
No work has been done since the previous repor t .
13-1 New Memory for the AVIDAC (4520-02)
Raymond F , K r a m e r
The AVIDAC m e m o r y , which is essent ia l ly a copy of the
Pr ince ton-Wi l l i ams tube memory ,has not been as re l iable nor does it have
the capaci ty and high r ead -a round ra t io of the ORACLE memory . Several
85
proposa ls have been made for improving the AVIDAC m e m o r y . Among
these is the proposa l to build an "ORACLE Type" m e m o r y using the special
RCA cathode ray type s torage tubes . Cost and t ime es t ima tes were p repa red
and submit ted for this pu rpose . The cos t is e s t imated at $ 128,000. 00 and
the const ruct ion t ime at nine months .
20-3 Report on R e s e a r c h , Development , and Design of the ORACLE
J. C. Chu (4520-02)
A repor t on the ORACLE is be ing p r epa red .
P a r t I, on logical des ign, is essent ia l ly complete .
P a r t II , on engineering design, is to be completed during the
ensuing qua r t e r .
21-4 Operat ion of the ORACLE (4520-02)
Raymond F . Kramer
The ORACLE was in operat ion on problems p r epa red by the
Oak Ridge staff until September 11 , 1953. One of these p rob lems used the
memory m its 2048 -word mode. It opera ted successful ly for th ree hours
in this manner .
The ORACLE was in operat ion until midnight of September l6th
on a r eac to r p rob lem p repa red by the ANL staff. Work on the p rob lem was
not completed because of previous p r o m i s e s to Oak Ridge to s t a r t dismantl ing
the machine on September 17th p r e p a r a t o r y to shipping.
86
8(o P r e p a r a t i o n for shipping the ORACLE was s t a r t ed as p romised
on September 17th. The packing cont rac tor began the work of boxing and
cra t ing the machine and the excess m a t e r i a l on September 24th. His
work was completed on October 1st. The packing requ i red 105 wooden
boxes and c r a t e s . It w^as loaded on two thirty-foot t ruck t r a i l e r s and s t a r t ed
i ts t r ip to Oak Ridge on October 6th, a r r iv ing there safely on the evening
of October 7th.
No further r e p o r t s will be made.
S'/
VIII. APPLIED MATHEMATICS AND COMPUTATION, GENERAL
1-4 IBM Methods and P r o c e d u r e s (5211-14)
N. F rank Morehouse
Special boards were wired for the computat ion of A s to be D ~
used by R. Meyerott in his opacity computat ions . The computations will be
analyzed and repor ted on by R. Meyerot t .
2-4 Report on Technical Details of General Purpose Boards (4520-02)
N. F rank Morehouse
The wri te-up of the fixed point board has been finished. This
comple tes the write-ups of the genera l purpose boa rds .
10-3 (Three-Group Calculat ion of Cr i t ica l Mass and Flux Plots) (4520-01)
B e r n a r d I. Spinrad and Katsumi Tanaka Reported by Katsumi Tanaka
No work has been done on this project during the q u a r t e r .
A manuscr ip t will be submit ted for publication in the Journal of Reactor
Science and Technology in the next q u a r t e r .
11-2 (Computations of the Absorpt ion of p Rays in Air) (5211-07)
The re su l t s of these computations a r e to be included in a
paper to be wr i t ten la te r by S. S. B r a r of the Division of Biological and
Medical Resea rch .
88
12-2 Computation of T r a c e s of Gamma Matr ices (5211-12)
Donald A. F l ande r s and Joseph Cook Reported by Donald A. F landers
Flow char t s along slightly different l ines have been cons t ruc ted
by each of the above. Neither flow cha r t has been p rog rammed .
