ANL 60 38 Phys ics and Mathematics (TID-4500, 15th Ed.) AEC Research and Development Report

ARGONNE NATIONAL LABORATORY P . O . Box 299

Lemont , I l l inois

PHYSICS DIVISION SUMMARY REPORT

July - August , 1959

Morton H a m e r m e s h , Division Di rec tor

P reced ing Sumnnary Repor t s :

ANL.-5955 - D e c e m b e r , 1958 - J anua ry , 1959 ANL,-5978 - F e b r u a r y - A p r i l , 1959 ANL-6020 - May - J u n e , 1959

August , 1959

Opera ted by The Univers i 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.

FOREWORD

The Summary Repor t of the Phys ics Division of the Argonne National Labora to ry is i s sued monthly for the information of the m e m b e r s of the Division and a l imited number of other p e r ­sons in t e re s t ed in the p r o g r e s s of the work. Each individual projec t r e p o r t s about once in 3 mon ths , on the a v e r a g e . Those not r epor t ed in a pa r t i cu la r i s sue a r e l is ted separa te ly in the Table of Contents with a re fe rence to the las t i s sue in which each appea red .

This is m e r e l y an informal p r o g r e s s r e p o r t . The r e su l t s and data the re fore mus t be unders tood to be p re l imina ry and ten ta t ive .

The i s suance of these r e p o r t s i s not intended to constitute publication in any sense of the word . Final r e su l t s ei ther will be submit ted for publication in r egu la r profess ional journals o r , in specia l c a s e s , will be p resen ted in ANL Topical R e p o r t s .

1

TABLE OF CONTENTS

The date of the las t preceding repor t is indicated after the t i t le

of each project below* P r o j e c t s which a r e not repor ted in this i s sue a r e

l i s ted on subsequent pages ,

I. EXPERIMENTAL NUCLEAR PHYSICS PAGE

11-22 INSTALLATION AND OPERATION OF THE VAN DE

GRAAFF GENERATOR (ANL-5978, F e b . - A p r i l , 1959)

Jack R. Wallace 1

Exper imen t s done with the genera tor a r e l i s ted . I m ­

provements and genera tor t roubles a r e d i scussed .

12-5 INTEGRATOR OF CURRENT IN AN ION BEAM (ANL-

5818, O c t . - D e c . , 1957)

F r a n k Lynch and Alexander Langsdorf, J r . . . . . , . 3

The project has been t e rmina ted with publication of a technical r e p o r t ,

98-22 NEUTRON TOTAL CROSS SECTIONS IN THE KEV REGION (ANL-5978, F e b . - A p r i l , 1959)

24 Most of the smal l r e sonances up to 350 kev in Na have been studied by self-detect ion m e a s u r e m e n t s and the ana lys i s of the r e sonances is in p r o g r e s s . The analyses have been completed in the region from 180 to 350 kev and the r e su l t s a r e included in this r e p o r t .

II. MASS SPECTROSCOPY PAGE

38-10 MASS SPECTROMETRIC STUDIES O F CHARGED ATOMIC AND MOLECULAR PRODUCTS OF NUCLEAR TRANSFOR­MATION ( A N L - 5 9 i l , A u g . - S e p t . , 1958)

G. R. Anderson and S. Wexler 15

P re l i rn ina ry studies on dissociat ion of mul t ip ly-charged DBr® ions formed by i s o m e r i c t rans i t ion of 4 . 4 - h r Br "^ indicate that l e s s than 5% of the DBr ions of each charge g r e a t e r than +3 r ema in bound. Atomic ions of Br with charges from +1 to +10 w e r e obse rved .

m . CRYSTALLOGRAPHY

4-1 CRYSTAL STRUCTURE STUDIES O F COMPOUNDS OF ELEMENTS A c - A m (New project)

H. A . P le t t inger and W. H. Zacha r i a sen . . . . . . . . . . 18

The complete c rys ta l s t r uc tu r e of sodium uranyl ace ta te has been de te rmined .

10-1 THE CRYSTAL STRUCTURE OF Li^WO^ (New project)

H. A. P le t t inger and W. H. Zacha r i a sen . . . . . . . . . . 23

The d imensions of the unit cel l have been m e a s u r e d . A p r e c i s e de terminat ion of a l l a tomic posi t ions is under way.

V. THEORETICAL PHYSICS, GENERAL

15-9 STATISTICAL PROPERTIES OF NUCLEAR ENERGY STATES ( former ly "Energy-Leve l Densi ty of a Sys tem of F e r m i P a r t i c l e s " ) (ANL-5884, J u n e , 1958)

N. Rosenzweig and C. E . P o r t e r . . 24

It has been found that the s ta t i s t i ca l p rope r t i e s of the ex­cited s t a tes of some complex a toms a r e the same a s those which have previous ly been d i scussed for neutron r e s o n ­ance s t a t e s .

I l l

PAGE

4 ELEMENTARY PARTICLES IN DeSITTER SPACE (former ly " P a r a m e t r i c Formula t ion of Quantum Mechanics") (ANL-5818, O c t . - D e c , 1957)

Will iam C. Davidon 29

The assumpt ion that space- t ime p o s s e s s e s the symmet ry of the DeSit ter group is being studied to develop the physical consequences for the p roper t i e s of e lementary p a r t i c l e s .

2 SOLVABLE FIELD THEORIES (ANL-5915, October , 1958)

H. Eks te in , 31

A paper enti t led "Equivalent Hamiltonians in Scattering Theory" has been wr i t t en . The main purpose is the for­mulation of a bas ic pr inciple for scat ter ing in field theory , in which the phys ica l -par t i c le creat ion opera to r s ra ther than the "basic f ie lds" a r e p r i m a r y en t i t i es . As a side r e s u l t , Hamiltonians equivalent in scat ter ing p r o c e s s e s a r e exhibited.

13 MESON-NUCLEON INTERACTION (ANL-5955 , Dec . , 1958-J a n . , 1959)

K„ Tanaka. . . . . . . „ „ o. . . .» 32

A possible fo rmal i sm that explains the difference between the m a s s e s of the charged and neut ra l species of both ir- and K-mesons is p roposed .

PROJECTS NOT REPORTED IN THIS ISSUE

A re fe rence to the l a s t preceding repor t i s given in parentheses for ch pro jec t .

EXPERIMENTAL NUCLEAR PHYSICS

1- The Argonne Fas t -Neu t ron Velocity Selector (ANL-5884, June , 1958), L. M. Bollinger and R. E . Cote ' .

2- Neutron Detec tors (ANL-5818, O c t . - D e c . , 1957), G. E . Thomas .

3- Cross-Sect ion Measu remen t s with the F a s t Neutron Velocity Sel­ector (ANL-6020, May- June , 1959), L . M. Bol l inger , R. E . Cote ' .

4 - Mass Distr ibut ion in F i ss ion (ANL-5818, Oct. -Dec . , 1957), L . M. Bollinger and G. E . Thomas .

7- Gamma-Ray Spect ra from Capture in Neutron Resonances (ANL-5978, F e b . - A p r . , 1959), L . M. Bol l inger , R, T . Ca rpen te r , a n d T . J . Kennett .

13- Ins t rumentat ion for T ime-of -F l igh t Neutron Spec t romete r (ANL-5818, O c t , - D e c . , 1957), F . J . Lynch.

14- Pu l sed Beam for the Van de Graaff Machine (ANL-5978, Feb . -A p r . , 1959), R. E . Holland and F . J . Lynch.

15- Stopping C r o s s Sections of Gases for Heavy Ions (ANL 5698, J a n . - M a r . , 1957), Mer le T . Burgy.

16- A New Neutron Counting System (ANL-5818, Oct. -Dec . , 1957), F . Pau l Mooring.

18- Differential C r o s s Section for Neutron Resonance Scat ter ing (ANL-5937, November 1958), Raymond O. Lane .

19- Nuclear Resonance Absorption of Gamma Rays at Low T e m p e r a ­t u r e s (ANL-6020, May-June , 1959), L . L . L e e , L . Meye r -Schl i tzmeis te r , J , P . Schiffer, and D. Vincent.

20- Energy States of Light Nuclei from Cha rged -Pa r t i c l e React ions (ANL-5754, A p r . - J i i n e , 1957), Linwood L e e , F . P . Mooring.

2 1 - Study of Geimma-Rays in Nuclear Reaction^ (ANii-5937, Nov. , 1958), Stanley Hanna and Luise Meyer -Sch i i t zmeis te r .

V

22- Scat ter ing of Charged P a r t i c l e s (ANL-6020, May-June , 1959), J . Yntema, B . Zeidman, and T . H. Bra id .

1 2 3

24- The Decay of Sn (125 days) (ANL-5852, A p r . , 1958), S. B. Bur son.

25- Angular -Dis t r ibut ion Measuremen t s of Charged-Par t i c le Reactions (ANL-6020, May- June , 1959), Linwood Lee and John Schiffer.

26- Measuremen t of Strength Functions (ANL-6020, May-June , 1959), John P . Schiffer and Linwood L . Lee .

27- Measu remen t s of Ene rgy -Leve l Density in Compound Nuclei P r o ­duced by Pro ton Bombardment (ANL-6020, May-June , 1959), L . L . L e e , R. S. P r e s t o n , N. Rosenzweig, and J . P . Schiffer.

28- Angular Cor re la t ions in Charged-Pa r t i c l e Reactions (ANL-5978, F e b . - A p r . , 1959), T . H. Bra id , J . L . Yntema and B . Zeidman.

29- S ing le -Par t i c le In te rpre ta t ion of Proton Spectra from (d,p) R e ­a c t i o n s (ANL-5911, A u g . - S e p t . , 1958), J . P . Schiffer, L . L. L e e , J r . , J . Yntema, and B . Zeidman.

34- The Decay of ggNd (12 min) (ANL-5915, October , 1958), L . C. Schmid, S. B. Burson .

1 6 1

36- Decay of Gd (ANL-5894, July , 1958), S. B . Burson , and L . C. Schmid.

1 1 3 i i 3 T n

37- The Decay of Sn (112 d) and In (1 . 73 hr) (ANL-5818, Oct. -Dec . , 1957), S. B . Burson and L . C. Schmid.

38- The Decay of Sm ^ (23.5 min) (ANL-5915, October , 1958), S. B . Burson and L. C. Schmidt

39- The Decay of P m (27.5 hr) (ANL-5937, November , 1958), S. B . Burson and L. C. Schmid.

1 4 9 40- Decay of P m (50 hr) (ANL-5955, D e c . - 1 9 5 8 , J an . -1959) ,

S. B . Burson and L. C. Schmid.

52- Gamma Rays from F i s s ion Induced by The rma l Neutrons (ANL-5818, O c t . - D e c , 1957), C. M. Huddle ston and C. C. T r a i l .

55- Capture G a m m a - R a y Spectra for Neutrons with Energ ies from 0. 1 to 10 ev (ANL-5915, Oct. , 1958), Sol Raboy and C. C. T r a i l .

58- Delayed Neutrons from F i s s ion (ANL-5955, D e c , 1958, J a n . , 1959), Gi lber t J . Pe r low.

60- 7 .7 -Mete r Ben t -Crys ta l Spec t rometer (ANL-5978, F e b . - A p r . , 1959), B. H a m e r m e s h .

80- Molecular Beam Studies (ANL 6020, May-June , 1959), William Chi lds , John Dalman, Leonard Goodman,and Lee Kieffer.

90- C r o s s Sections for 14-Mev Neutrons (ANL-5955, D e c , 1958, Jan . , 1959), Harvey Casson and L . A. Rayburn .

102- Neutron Cros s Sections by Self-Detection (ANL-5978, F e b . -A p r . , 1959), J a m e s E . Monahan.

UO- Storage of Pulse-Height Data on Magnetic Tape (ANL-5955, D e c , 1958, J a n . , 1959), Jcimes Baumgardner .

115- High-Tempera tu re Diffusion Cloud Chamber (ANL-6020, May-June , 1959), Char les M. Huddle s ton.

123- The Symmetry P r o p e r t i e s of Neutron Decay (ANL-5815, Oct. , 1958), Mer le T . Burgy, V. E . Krohn, T. B . Novey, Roy Ringo, and V. L. Telegdi .

125- Pos i t ron Polar iza t ion Demonst ra ted by Annihilation in Mag­net ized Iron (ANL-5818, O c t . - D e c , 1957), S. S. Hanna and R. S. P r e s t o n .

129- The Helicity of the Neutr ino Emit ted in the E lec t ron -Capture Decay of Bery l l ium-7 (ANL-6020, May-June , 1959), T . B . Novey, P . R i c e - E v a n s , and V. L . Telegdi .

144- Investigation of Scint i l la tors (ANL-6020, May-June , 1959), War ren L . Buck, Louis J . Basi le ,and R. K. Swank.

MASS SPECTROSCOPY

18- Lead Ages of Meteor i t es (ANL-5868, May, 1958), D . C . H e s s .

19- Measurement of Silver from the Troi l i te Phase of a Meteor i te (ANL-5818, O c t . - D e c , 1957), D . C. H e s s .

20- T r i t i um Age Measuremen t s of Meteor i t es (ANL-6020, May-J u n e , 1959), David C. H e s s .

28- Kinet ics of Chemical React ions in the Gas Phase (ANL-5818, O c t . - D e c , 1957), Will iam A. Chupka.

VI1

29- Gaseous Species in Equi l ibr ium at High Tempera tu re s (ANL-5911, A u g . - S e p t . , 1958), M. G. Inghram and Wm. A. Chupka.

40 40 34- A - K Dating of Meteor i tes (ANL-5818, O c t , - D e c . , 1957),

D. C. H e s s .

35- Method of Measur ing Appearance Potent ials (ANL-6020, May-June , 1959), H. E . Stanton.

39- Kinetic Energy of Organic Radicals (ANL-5818, Oct. -Dec . , 1957), W. A. Chupka and H. E . Stanton.

40- Fragmenta t ion of Organic Molecules (ANL-5955, D e c , 1958^ J a n . , 1959), Henry E . Stanton.

CRYSTALLOGRAPHY

1- Crys ta l Studies of Technet ium Compounds (ANL-5412)^ Will iam H. Zacha r i a sen .

2- S t ruc tu ra l Studies of Boric Acid (ANL-5412)^ H. Anne P le t t inger .

5 - The Crys ta l S t ruc ture of K UO^ F , Wm. H, Zachar iasen ,

6- Studies of Cur ium Compounds (ANL-5412)^ Wm. H. Zacha r i a sen .

THEORETICAL PHYSICS, GENERAL

3- Dynamics of Nuclear Collective Motion (ANL-5754j, Apr . -June , 1957), David R. Ing l i s , Kiuck Lee .

4 - Investigation of Nuclear St ructure (ANL-5955, D e c , 1958-Jan . , 1959), Mar ia Goeppert Mayer .

7- Beta Decay of Ip-Shel l Nuclei (ANL-5955, Dec . , 1958-Jan, , 1959), D. Kura th .

8- Relat ionships of Collective Effects and the Shell Model (ANL-6020, May- June , 1959), D. Kurath .

17- Analysis of Angular Dis t r ibut ions and Corre la t ions (ANL-6020, May- June , 1959), Wm. C. Davidon,

4 3 - Fie ld Theory of Nonrela t iv is t ic Moving Nucleons (ANL-5818, O c t , - D e c . , 1957), H. Eks te in , D. Kaplan.

V l l l

4 8 - Dispers ion Relat ions (ANL-5786, July-Sept . , 1957), Wm. C. Davidon.

54- The Polar iza t ion of Nucleons by Deuterons (ANL-5894, Ju ly , 1958), Kenneth Smith and Mur ray Peshk in .

1-11-22 1

EXPERIMENTAL NUCLEAR PHYSICS

11-22 Instal la t ion and Operat ion of the Van de Graaff Generator (5220)

Jack R. Wallace

This r epo r t covers the operat ion of the Van de Graaff genera tor in

the Phys i c s Division for the per iod Apr i l 1 to June 30, 1959, inc lus ive .

The genera to r was used to a c c e l e r a t e p ro tons , deuterons, and alpha

p a r t i c l e s . The genera to r voltage was from 900 kev to 4. 2 Mev, Beam cur ­

ren t s m e a s u r e d at the t a rge t va r i ed from 0. 1 m i c r o a m p e r e to 30 m i c r o a m ­

p e r e s .

The following l i s t shows the division of t ime and types of exper iments

being pe r fo rmed with the Van de Graaff genera tor by the group . No effort has

been made to show any efficiency factor for the use of the al lot ted t ime given

to the var ious e x p e r i m e n t e r s .

1 4 1 5 1. N ( P , ' Y ) 0 L e e , Meyer , Vincent 9 0 . 2 h r

1 9 1 6 2. G a m m a - r a y s tudies on F ( p,, a Y ) 0

Huizenga, Raboy, T r a i l 163. 1

3. P ro ton polar iza t ion Schiffer, Smither 108,7

4. Tota l neutron c r o s s sect ions in the kev region Hibdon 128.5

5 . (P,"Y) s tudies of many nuclei L e e , Meyer , Raboy, Schiffer, T r a i l , Vincent 345.2

6. Li fe t imes of excited s ta tes by pu l sed-beam technique

Holland, Lynch 118.0

7. Total c r o s s - s e c t i o n s tudies L e e , Mooring, Lane 116.4

8. Cal ibra t ion check on counter Per low 5,0

1-11-22

9, Half-life m e a s u r e m e n t s L e e , Meyer , Vincent 29 .3

Total 1104.4

S ta r t -up and daily maintenance 45 .5

Machine r e p a i r s and exper imenta l setup 210.1

Total t ime avai lable [65 days X 16 hr + 26 days X 8 hr + 14 days X 8 hr (midnight shift) ] 1360. 0 hr

Bearing fai lure in var ious components of the Van de Graaff gene ra ­

tor has been quite high. This shor t life of bear ings could be caused by a

number of things such a s : (1) Breakdown of lubr ica t ion—poss ib ly caused by

gases used or formed in the gen ra to r , (2) Inadequate cooling. (3) P r e s e n c e

of high e l ec t r i c f ie lds . (4) Inaproper bear ing t o l e r a n c e . (5) Bad choice of

bear ings for intended job.

A bear ing spec ia l i s t was cal led in to d i scuss these p r o b l e m s . Each

component that had bear ing failure was examined for evidence to indicate what

might be causing the fa i lu re . Number four of the above l i s t s eemed to be the

answer in a l l c a s e s . A different lubr icant was r ecommended a l s o . The

machine shop made the suggested changes on the respec t ive bear ing t o l e r ­

a n c e s . No further bear ing fai lure has occu r r ed to da t e .

The bear ings of the 15-hp motor driving the belt failed mos t f r e ­

quently. Upon examination it was found that the motor manufac tu re r had

violated s eve ra l sound p r ac t i c e s recommended by bear ing m a n u f a c t u r e r s . A

t e m p o r a r y co r rec t ion was m a d e , but a new motor from a different manufac turer

seemed d e s i r a b l e . A new motor has been bought and ins ta l led and no further

bear ing fai lure has o c c u r r e d to da te .

Work is s t i l l being done in an effort to extend the life of the charging

be l t . A new bel t manufac ture r has been found and a different type of bel t o r ­

dered that might be an improvement on the type of belt now being used .

1-12-5 1-98-22

12-5 In tegra tor of Cur ren t in an Ion Beam (5220)

F rank Lynch and Alexander Langsdorf, J r . Repor ted by F rank Lynch

A technical r epo r t descr ibing the in tegra tor appeared in Rev. Sci.

I n s t r . 30, 276-279 (April 1959), This t e rmina t e s the pro jec t .

98-22 Neutron Total C r o s s Sections in the Kev Region (5220)

Ca r l T . Hibdon

MEASUREMENTS OF SODIUM 24

The study of the nuclear levels of Na has been continued by use

of the same techniques and sodium samples descr ibed previous ly . During

previous m e a s u r e m e n t s it was found that the widths of many of the levels a r e

too smal l to be reso lved sufficiently by flat detection to de te rmine their p a r a ­

m e t e r s . It was found that these peaks could be resolved bet ter by self-

detection and hence the i r p a r a m e t e r s could be more re l iably de te rmined .

T h e r e f o r e , the l a tes t m e a s u r e m e n t s were devoted al inost ent i re ly to self-

detect ion. Most of the peaks up to 350 kev have been studied by this method

and an ana lys i s of these peaks is in p r o g r e s s . The analyses have been com­

pleted in the region from about 180 to 350 kev and a r e given in the following

sec t ions . To date a tota l of 127 peaks have been observed up to 500 kev.

1

Phys ics Division Summary Repor t , ANL-5978 (Feb. - A p r i l , 1959), p , 14,

1-98-22

A. Analysis of the Resonance Levels from 180 to 240 kev

The la rge resonance observed by Stelson and P res ton

just above 200 kev was found to be composed of two p e a k s , Nos. 42 and 43 ,

shown in the upper curve of F ig . 1 in which points obtained by self-detection

a r e r ep resen ted by solid c i rc les and those obtained by flat detection a re r e ­

presented by open c i r c l e s . The splitting of this resonance into two peaks

was observed twice by flat-detection m e a s u r e m e n t s and la ter by self-

detection. The combined configura­

tion of these two peaks together with

the overlapping wings of other n e a r ­

by peaks indicates that No. 42 can

be expected to be a re la t ively

narrow p - or d-wave resonance .

The high value of the c ros s s e c ­

tion in the h igh-energy wing of

Nos. 42 and 43 indicates an s-wave

neutron interact ion for No. 43 . By

t r i a l and e r r o r it was found that the

most reasonable fit for Nos. 42 and

43 could be obtained only by assuming

No. 43 to be an s-wave resonance .

Resonance No. 42 is then located at

the minimum of No. 43 and hence

this minimum d e p r e s s e s the pecik

of No. 42 and a lso d i s tor t s the shape

of the resonance . This distort ion

is c lear ly recognizable in F ig . 1.

Repeated a t tempts to analyze this

pair of resonances indicated that

a best fit could be obtained by tak-

2 0 0 210 E„ ( K e v )

2 2 0 240

Fig . 1. Neutron total c ros s section (upper curve) of sodium from 180 to 240 kev. Open c i rc les show data obtained by flat detection; solid c i rc les ,da ta by se l f -de tec­tion. Curve A is a s ingle- level plot for resonance No. 42 and includes the low-energy wing of No. 49 and the s-wave levels at higher energy. Curve B r e ­p resen t s the difference between the data and curve A.

P . H. Stelson and W. M. P r e s t o n , P h y s . Rev. 88, 1354(1952).

1-98-22 5

ing a value of J = 3 for No, 42 with

r = 1. 8 kev and i = 1, although a

value of i = 2 can not be unam­

biguously ruled out. After the

ana lyses were completed, the self-

detection data near the peak of No.

42 were cor rec ted for the depress ion

caused by the min imum of No. 43 .

The cor rec ted points a r e r e p r e s ­

ented by c r o s s e s in the upper curve

of F ig . 1. The highest cor rec ted

point is then ve ry near the possible

value for J = 2 and ru les out this

value of J because a resonance of

this width can not be expected to

be resolved to a height so near i ts

t rue value . Curve A in F ig . 1 in­

cludes the potential sca t t e r ing , the

combined s ingle- level plots of No.

240

Fig . 2. Analysis of the resonances in the region from 180 to 240 kev. Curve C shows the mul t i ­ple- level s-wave plot for Nos. 43 and 50. Curve E is a single-level plot for No. 48. Curve D from 180 to 200 kev has been correc ted for the low-energy wings of resonances Nos. 43 and 48. The potential sca t t e r ­ing is not included in any curve.

42 and No. 49 (J = 2, i = 1), the s-wave level No. 60, and the level at

542 kev. The wings of the s-wave l eve l s , which were computed by the

mul t ip le- level d i spers ion formula , show that the c ros s section is depressed

throughout this region. By subtracting curve A from the data in F ig , 1, one

obtains the two pa r t s of curve B , which a r e then t r ans fe r r ed to curve D

of Fig , 2.

Because of i ts apparent a symmet r i ca l shape and on the bas is

of the t r i a l - a n d - e r r o r fit mentioned above, peak No. 43 is taken to be an

s-wave resonance . The m e a s u r e d peak height is close to the theoret ical ly

possible height for J = 1. Use of smal le r neutron energy spreads would

not be expected to resolve a resonance of this apparent width to any

appreciably higher peak value. Therefore it is considered well resolved

1-98-22

° "S \ \! r; \

180 190 200 210 En(kev)

220 230

Fig . 3. Analysis of the resonances from 176 to 230 kev. The poten­t ia l scat ter ing and the wings of s-wave levels were removed by the subtract ions shown in F i g s . 1 and 2. The dashed s ingle-and mul t ip le- level plots show the bes t fits for the r e sonances .

and J has a value of 1. Curve C

in F ig . 2 is a mul t ip le- level plot

of the s-wave levels Nos. 43 and

50, obtained by the p a r a m e t e r s

shown in Table I. These p a r a ­

m e t e r s were f irs t obtained by

t r i a l and e r r o r and la ter confirmed

by the computer GEORGE. The

mutual in te r ference of these two

levels lowers the peak height of

No, 43 below the s ingle- level

height and elevates the peak of

No, 50 above i ts s ingle- level

height as shown by curve C in

F ig . 2 and curve E in F ig , 5,

Because of the

a symmet r i ca l shape of peak No,

48 , it i s also taken to be an s-wave re sonance . Its re la t ively nar row width

prevents one from resolving i t s peak to a height sufficient to dist inguish

c lear ly between the two possible values of 1 and 2 for J . But the degree

to which it is r eso lved , par t i cu la r ly by self-detect ion, shows a preference

for a value of J = 2. Moreover , one can account for the h igh-energy wing

of this resonance m o r e easi ly with a value of J = 2. By t r i a l amd e r r o r it

was found that a best fit occurs for a width of 0, 90 kev. The s ingle- level

plot for the p a r a m e t e r s J = 2, r = 0.90 kev and i = 0 is shown as curve E

in Fig . 2. Curves C and E a r e then subtracted from the data to obtain the

two pa r t s of curve F in F ig . 3.

All of the peaks in the group comprising Nos . 44 to 47 in­

clusive (Fig. 3) appear to be symmet r i ca l in shape so they a r e taken to be

p - or d-wave r e sonances . The fairly deep minimum (revealed by self-

detection) between Nos, 44 and 45 is indicative of mutual in ter ference

1-98-22 7

between this pa i r of resonances , and the same is t rue for Nos . 46 and 47, In view

of these min ima and the re la t ive observed heights of these peaks , it is unlikely

that a l l four peaks a r e a t t r ibutable to the same value of J, Mutual in ter ference

is not indicated between Nos . 45 and 46 because they a r e far enough apar t that a

deep min imum would have been observed if p r e sen t . The self-detect ion data in­

dicate a value of J = 2 for Nos . 44 and 45 and a value of J = 1 for Nos, 46 and 47.

The mul t ip le - leve l plots shown in F ig . 3 were obtained by use of the p a r a m e t e r s

shown in Table I . These plots do not fully account for the var ious minima but

a r e about as compatible with the var ious a spec t s of the data as one can expect .

The deep min ima shown by the mul t ip le - leve l plots a r e not reso lved to that extent

exper imenta l ly because (a) the val leys a s well as the peaks a r e too nar row to be

fully r e so lved , and (b) overlapping wings of neighboring resonances elevate these

min ima above what is shown by the mul t ip le- level p lo t s , and (c) one can not rule

out the poss ibi l i ty of the p r e s e n c e of other nar row unresolved r e s o n a n c e s .

In the region below 200 kev one finds no indications of s-wave

r e s o n a n c e s . The observed peak heights of Nos . 37 and 38 a r e higher than the

theore t i ca l value for J = 0, but they a r e wide enough that thei r peaks would be

expected to be considerably h igher if J we re to be 1, Moreove r , the over ­

lapping wings of other n e a r - b y levels elevate the peaks somewhat. F u r t h e r ,

the min imum between these peaks indicates mutual in te r fe rence . This will

e levate both peaks above the i r s ing le - leve l height . The re fo re , J i s taken to be

0 for both r e s o n a n c e s . The i r widths indicate a value of i = 1. The mul t ip le-

level plot of N o s . 33 through 38 inc lus ive , obtained by a width of 1, 9 kev for

No, 37 and a width of 2 . 1 kev for No. 38, i s shown in F ig , 3, This plot accounts

v e r y wel l for these two p e a k s . The value of J is tciken to be 1 for peaks Nos ,

39 to 41 inclusive because of the i r approximate ly equal peak he igh t s . The appa r ­

ent widths of these levels a r e too na r row to r e so lve to thei r t rue peak heights

but sufficiently wide that one would have reso lved the peaks to g rea t e r heights

1-98-22

T A B L E 1. S u m m a r y of t he l e v e l s of Na f r o m 175 k e v to 350 k e v d e r i v e d f r o m n e u t r o n r e a c t i o n s wi th Na . The p a r a m e t e r s J , r and i a r e p r o b a b l e v a l u e s ob ta ined a s a b e s t fit to the d a t a . The quant i ty v .^ i s the r e d u c e d width ob ta ined by the r e l a t i o n I ^ = 2 P Vi^" E > F and -y a r e e x p r e s s e d in k e v .

No . ^0

37

38

39

40

41

4 i A

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

59A

60

61

62

63

63A

64

6 4 A

65

65A

66

67

67A

178.4

182.6

188.0

193.0

196.7

199.5

202.7

205.2

213.7

218.2

224.0

227.7

231.9

242.0

246.3

255.0

260.5

264.7

268.5

272.8

278.5

287.0

290.7

294.7

298.0

302.5

306.5

311.6

316.50

321.0

324.0

326.8

330.8

334.2

338.3

343.6

346.0

1.9

2 . 1

1.6

1.2

1.1

0 . 7

1.8

3.6

1.3

1.2

1.7

1.7

0.90

6.0

3.0

1.3

1.7

0.9

1. 1

1.1

1.3

1.3

0.9

1.3

2 . 0

2 . 5

1.6

1.5

0.9

0.9

1. 3

0.9

2.0

1.0

1.7

1.0

0 . 7 5

1

1

1

2(1)

2(1)

2

1

0

1(2)

1(2)

1(2)

1(2)

0

1

0

2

2(1)

2

2

2

2

2

2

2

2

0

2

2

3(2)

3(2)

2

3(2)

2

3(2)

2

3(2)

3(2)

4.7

1.1

3.57

2.7

2 4 . 1

2 5 . 8

18 .9

1 3 . 6

12 .2

7 . 6

1 9 . 2

1 2 . 9

11 .6

1 5 . 8

1 5 . 4

837

735

450

1119

706

621

825

795

5 0 . 2

10.6

12.5

6 . 7

7 . 8

9 . 8

8 . 9

7 . 4

11.0

9 . 1

422

548

291

329

328

363

345

230

323

473

362

326

188

182

257

175

376

183

300

174

128

1-98-22

for a value of J = 2. The minimum between Nos, 39 and 40 is not as deep

as would be expected if t he re was mutual interference between resonances

as well separa ted as t hese . On the other hand, mutual interference is a s ­

sumed for peaks Nos. 40 and 41 because of the deep minimum between them.

The self-detection data show that peak No. 41A is high and narrow with

J ^ 2. Because of the nature of the data presented by the foregoing a rgu­

m e n t s , one mus t then neces sa r i l y ass ign a value of i = 1 to No. 39 and

i = 2 to Nos, 40, 41 and 41 A. The var ious plots obtained by the widths

tabulated in Table I a r e shown in F ig , 3 and the sum of the plots appears

to agree with the data except near the peaks .

B. Analysis of the Resonance Levels from 240 to 290 kev

Two different measu remen t s were made by flat detection

over the region of peaks Nos . 49 and 50. The data a r e shown in the upper

curve of F ig . 4 , the points obtained in one run being represen ted by open

c i rc les and those of a second run by c r o s s e s . Resonance No. 49 is the

predominant peak of this region and is the widest observed peak up to 500

kev. The wings a r e sufficiently revealed to show that it is symmet r ica l in

shape. Because of i ts la rge width, it is at tr ibutable to a p-wave neutron

in terac t ion . Also because of i t s l a rge width, this resonance is undoubtedly

F ig . 4 . Neutron total c ro s s s e c ­tion (upper curve) of sodium from 230 to 290 kev. Open c i rc les show data obtained by flat detection; solid c i rc les , data by self-detect ion. Curve A is a s ingle- level plot for r e ­sonance No. 49, It includes the high-energy wing of No, 42 and the wings of s-wave levels at higher energy. Curve B r e ­p resen t s the difference between the data and curve A.

230 240 250 260 En (kev)

270 280 290

1-98-22

4

b-2

1

0

•

48

L r

&

%

--~, 1

50|ft

a/'

•

•

* •

V VVv ".?-- -

1 1

j . i 7 8-1

. .

vWt '

1 1

— -

K ^ .

.

A"

260 En (kev)

280 290

Fig . 5. Analysis of the resonances in the region from 230 to 290 kev. Curve E shows the m u l ­t ip le- level s-wave plot for r e ­sonances Nos . 43 and 50. Curve C has been cor rec ted for the low-energy wing of resonance No. 50. The po­tent ia l sca t ter ing is not in­cluded in any curve .

well resolved and a value of J = 2

appears to be cer ta in . It is to be

noted, however, that the low-energy

wings of the s-wave level No. 60 and

the one at 542 kev extend into this

region and therefore d e p r e s s the

c ro s s section everywhere in the r e ­

gion. Consequently the apparent

peak height of resonance No. 49

should fall below the theore t ica l

s ingle- level value for J = 2 even

with perfect resolut ion. The curve

designated by A in F ig . 4 is a

s ingle- level plot obtained with a

width of r = 6.0 kev and i = 1. It

includes a s ingle- level calculation of the high-energy wing of No. 42 and

also the low-energy wing of the s-wave level No. 60 and of the s-wave r e ­

sonance at 542 kev. The low-energy wings of these s-wave levels were

calculated from the mul t ip le- level formula. The two pa r t s of curve B in

F ig . 4 were obtained by subtracting curve A from the data and were then

t r a n s f e r r e d to F ig . 5 where they a r e labeled C and D. The analysis of

resonance No, 48 is shown in F ig . 2,

With any reasonable widths of the resonances in the

neighborhood of peak No, 50, subtracting their wings from the data yielded

an a s y m m e t r i c shape for the la t ter peak. In pa r t i cu l a r , the c ro s s section

in the high-energy wing of No. 50 is so high that an s-wave neutron in t e r ­

action seems to provide the only possible means of accounting for i t . Be ­

cause of i ts width, this resonance is near ly completely resolved and the

value of J is therefore taken to be 1. Curve E in F ig , 5 is a mul t ip le- level

plot of the s-wave resonances Nos . 43 and 50 and is a continuation of curve

C in F ig . 2,

1-98-22

It i s understandable that resonance No. 49, although

6 kev wide, is not resolved to i ts t rue s ingle-level peak height for a value

of J = 2. This is at t r ibutable in pa r t to the depress ion of the c ros s s e c ­

tion in this region by the s-wave levels at higher energies and in par t to the

fact that No. 49 is located very near the minimum of No. 50; but this ex­

t r a depress ion caused by the nainimum of No. 50 is most ly offset by the

high-energy wing of the s-wave resonance No. 48 and the wings of other

neighboring r e sonances . The calculated curve A in Fig . 4 includes the

wing of the s-wave resonance No. 60 and of the one at 542 kev plus the high-

energy wing of No. 42. The peak height of this curve can be seen to be a

few tenths of a barn below the s ingle- level height of No. 49. The close

agreement of the calculated and observed peak heights of No. 49 then

se rves to indicate that the assximed value of the potential scat ter ing c ros s

section in this region is close to i ts t rue value. Resonance No. 50, hav­

ing a width of 3 kev , might a lso be expected to be resolved very near ly to

i ts t rue peak height but one sees in

F ig , 5 that it i s slightly below the

mul t ip le- level va lue . However, the

mul t ip le- level plot (curve E in F ig .

5 has not been cor rec ted for the

wings of neighboring resonances

and therefore will be slightly higher

than the observed peak height of

No. 50.

By subtracting

curve E in F ig . 5 from curve D

one obtains the curve shown in F ig .

6. All of the peaks in this group

(Nos. 51 through 59A) appear to

be symmet r i ca l in shape and a r e ,

t he re fo re , a t t r ibutable to p - and

ances from 250 to 300 kev. The potential scat ter ing and wings of s-wave levels were removed by the subtractions shown in F i g s . 4 and 5. The dashed single- and mult iple-level plots show the best fits for the r e sonances .

1-98-22

d-wave neutron in te rac t ions . The var ious s ingle- and mul t ip le- level plots

shown in Fig . 6 were obtained by use of the p a r a m e t e r s tabulated in Table

I. These p a r a m e t e r s were de termined by t r i a l and e r r o r . Peak No, 56A

is a spurious reflection of the 2 .95-kev resonance and a r i s e s because of 3

the second group of low-energy neutrons in the beam. This peak is t h e r e -a4

fore not included among the levels of Na

C, Analysis of the Resonance Levels from 290 to 350 kev.

The data for th is region a r e shown by the upper curve

in F ig . 7 , where open c i rc les r ep re sen t points obtained by flat detection

and closed c i r c l e s the points obtained by self-detect ion. Peak No. 60 is

the predominant resonance in this

region and c lear ly shows a p r o ­

nounced minimum on its low-ener ­

gy s ide . I ts shape, although

modified to some extent by neigh­

boring peaks , i s st i l l dist inctly

a s y m m e t r i c a l and therefore is

c lear ly at t r ibutable to an s-wave

neutron in teract ion. The observed

peak height is 5.5 barns (including

the potential scattering) compared

with theore t ica l s ingle- level heights

of 4 .6 and 6 .4 barns for J = 1 and 2 ,

respec t ive ly . Mutual in ter ference

with the s-wave resonance at 542

kev can be expected to reduce the

peak height of No. 60 considerably

because of the l a rge width of the

310 320 £ „ ( » . . )

Fig . 7. Neutron total c ro s s s e c ­tion (upper curve) from 288 to 348 kev. Open c i r c l e s sho-w data obtained by flat detection; solid c i rc les , data by se l f -de­tect ion. Curve A is the mul t i ­p le- level s-wave plot of r e ­sonance No, 60 and the s-wave level at 542 kev. It a lso in­cludes the mul t ip le- level plot of r esonances Nos . 43 and 50. Curves B and C were obtained by subtracting curve A from the data .

C. T. Hibdon, Phys , Rev. 108, 414 (1957); 114, 179 (1959).

1-98-22 13

fo rmer . The re fo re , the value of

J is taken to be 2. By a d i rec t

examinat ion, one can see that the

width is approximately 2.5 kev.

This was confirmed by a mul t ip le-

level plot for this resonance and

the resonance at 542 kev. This

plot is shown by curve A in F ig .

7 , which a lso includes the con­

tr ibution of the mul t ip le- level

plot of r esonances Nos . 43 and

50 (J = 1, i = 0). By subtracting

this curve from the da ta , one

obtains curves B and C, Only

curve C is then t r a n s f e r r e d to

F ig . 8, curve B being included in

310 320 330 E„ (kev)

3 4 0 350

Fig , 8, Analysis of the resonances from 306 to 350 kev. The po­tential scattering and wings of s-wave levels were removed by the subtraction shown in Fig , 6. The best fit is shown by the dashed curves obtained by the appropria te single- and naultiple-level computations.

F ig . 6. Peak No, 61 i s a t t r ibu t ­

able to J = 0 and a s ingle- level plot for I^ = 1. 6 kev and i = 2 is shown

by curve D in F ig . 7 , th is being about the best fit in view of the wings of

the neighboring l eve l s .

No wide peaks or s-wave resonances a re left in the

region from 300 to 350 kev. The peak heights obtained by self-detection

for the f i r s t four peaks indicate that no peak has a value of J l e ss than 1

and the re la t ive ly na r row widths indicate d- and f-wave neutron in te r ­

ac t ions . The observed peak height of No. 63 (self-detection) is near the

possible value for J = 1 and, for a resonance of this apparent width, one

could expect by use of smal le r neutron energy spreads to resolve this

peak to a considerably higher value which would be at leas t sufficiently

high to ru le out a value of J = 1. Since the flat-detection data show

s imi la r heights and widths for Nos . 63 and 67, the value of J is tciken to

be 2 for these two r e sonances . Peaks Nos. 62, 64, 65 and 66 a r e then

1-98-22

a t t r ibutable to J = 1 because they a r e wider than Nos . 63 and 67 and the i r

peaks a r e not as high (self-detection) . The self-detect ion data on peak

No. 63A a lso indicate a value of J = 1 for th is peak and it is then reasonable

to conclude the s ame for Nos . 64 A, 65 A and 67 A. These la t te r peaks a r e

so na r row that the value of i i s 2 , or preferably 3^ for t h e m . The appropr ia te

s ingle- and mul t ip le - l eve l plots a r e shown in F ig . 8. Single- level plots a r e

shown for N o s . 63 and 67 for i = 3 and a s ingle- level plot i s shown for Nos .

62, 64, 65 and 66 for i - Z. A mul t ip le - leve l plot is shown for Nos . 63A;

64 A, 65 A and 67 A (i = 3). Although this mul t ip le - leve l plot was obtained

for i = 3 , it differs l i t t le from the one obtained for i = 2. These plots were

obtained by use of the p a r a m e t e r s shown in Table I . The widths were d e t e r ­

mined by t r i a l and e r r o r . The widths of these r e sonances a r e re la t ive ly

na r row and it i s en t i re ly poss ible that one or m o r e of them could be r e ­

solved to higher values of J by appropr ia te neutron energy s p r e a d s . On

the other hand, the i r widths a r e sufficiently wide that one can hard ly expect

to reso lve them to heights much above those heights corresponding to the

ass igned values of the J ' s . The corresponding reduced widths a r e so

sma l l that one expects that i > 2 for Nos„ 6 1 , 62 , 65 and 66 and i = 3

for al l o t h e r s .

PAPERS

A. A paper entit led "Distr ibut ion of the Angular Momenta , Level Spacings and Neutron Widths of Al " has been published in the P h y s i ­cal Review. [Phys„ Rev„ 114, 179 (1959).

B . A paper enti t led "Distr ibut ion of Angular Momenta of R e ­sonance Levels for Neutron Sca t te r ing" appeared in the P roceed ings of the Second Internat ional Conference on the Peaceful Uses of Atomic E n e r g y , Geneva, 1958. (United Nat ions , Geneva, 1959), Volo 15, p . 72,

24 ,, C. A paper entit led " T h e r m a l Neutron V for Pu by Ar thur

H. Jaffey, Ca r l T. Hibdon,and Ruth Sjoblom has been accepted for publication in the Journa l of Nuclear Ene rgy .

11-38-10 15

II . MASS SPECTROSCOPY

38-10 Mass Spec t romet r i c Studies of Charged Atomic and Molecular P roduc t s of Nuclear Transformat ion (5220)

G. R. Anderson and S. Wexler Repor ted by S. Wexler

A. BOND RUPTURE OF DBr "^ FOLLOWING NUCLEAR ISO­MERIC TRANSITION

When 4o4-hr , Br undergoes i s o m e r i c t r ans i t ion , i t s 18-min

daughter may be expected to r ece ive a high positive charge . The t rans i t ion

occurs by in te rna l conversion with loss of e lect rons by conversion and Auger 1

c a s c a d e s . A mean charge of + lOe has been m e a s u r e d by d i rec t cur ren t

methods for the products frona decay of C^H Br . Snell and Pleasonton, 1 3 1 m .

using m a s s s p e c t r o m e t r i c t echn iques , have shown that when Xe decays

by in te rna l convers ion , a peaked distr ibution of charged daughter ions r e s u l t s ,

the charges ranging from +1 to +22. The average charge is found to be

+7. 91 e in good a g r e e m e n t with the value of +8. 5e m e a s u r e d by P e r l m a n 3

and Miske l .

If the radioact ive Br is at tached to deuter ium pr io r to the

t r ans fo rma t ion , the question a r i s e s whether the immedia te daughter ion 80

DBr can survive dissocia t ion when it has a high posit ive charge . Several inves t iga tors have a d d r e s s e d themse lves to this p rob lem. Hamill and

S. Wexler , P h y s . Rev. 93 , 182 (1954). 2

A. H. Snell and F„ P leason ton , P r o c . Roy. Soc. (London) A241, 141 (1957). 3

M. L . P e r l m a n and J . A. Miske l , P h y s . Rev. 9 1 , 899 (1953).

11-38-10

4 80 Young found that about 15% of the DBr r ema in bound, while about 25%

80 of the HBr a r e undissocia ted when tagged hydrogen bromide is the g a s .

5

More recen t ly , Luebbe and Willard r e m e a s u r e d the extent of bond rupture

in HBr and found it to be 93%. However , both exper iments were done

with gases a t high p r e s s u r e s , wherein coll is ions ajid dissociat ion by charge

neut ra l iza t ion p r o c e s s e s may contribute to b reak -up of the diatomic molecvile. 6

Theore t ica l a rgumen t s of Magee and Gurnee suggest that highly charged +n "

(HBr) spec ies m a y be s t ab le . But Johnston and Arnold failed to detect HBr ions of charge +3 and +4 by e lec t ron impact in a m a s s s p e c t r o m e t e r ,

1+ 2+

although HBr and HBr were obse rved .

In o rde r to r e so lve the p rob lem d i rec t ly by observa t ions on

iso la ted molecules undergoing i s o m e r i c t r ans i t i on , DBr of high specific

act ivi ty has been int roduced at low p r e s s u r e into the improved model of the

m a s s spec t rome te r for radioact ive g a s e s . The re la t ive in tens i t ies of B r

and DBr of a given charge w e r e m e a s u r e d . In p r e l i m i n a r y findings Br

was observed with n ranging from +1 to +10, while the r a t io DBr / B r J.2 + 2

was l e s s than 0.05 for n = 3 through 10; and DBr / B r was 1.4 + 0 . 2 ,

The in tens i t ies of the singly-charged spec ies w e r e found to be obscured by

se l f - radia t ion of the bulk gas by act ive m a t e r i a l deposi ted on the wal ls of

the soxxrce volt ime. No D ions were de tec ted . W. H. Hamil l and J . A . Young, J . C h e m . P h y s . 20 , 888 (1952).

R. H. Luebbe , J r . , and J . E . Wi l la rd , J . Chem. P h y s . 29_, 124 (1958). 6

J . L . Magee and E . F . G u r n e e , J . Chena, P h y s . 20 , 894 (1952).

W. H. Johnston and J . R. Arnold , J . Chem. P h y s . 2 1 , 1499 (1953).

11-38-10 17

B. DISSOCIATION OF i ,2-C^H^BT^^'^ BY INTERNAL CONVERSION

Fur the r studies of the fragmentation of 1,2-C H Br°*^"^ by

nuclear decay were m a d e . The fragmentation pat tern observed was s imi lar 8

to that obtained ea r l i e r with the original design of the spec t romete r . In

addition to seve ra l f ragments containing carbon, a spect rum of charged Br

ions was found ranging from +1 to about +15. The peak in the distribution

was at approximate ly +6.

C. MODIFICATION OF THE MASS SPECTROMETER FOR RADIOACTIVE GASES

The original spec t romete r was dismantled and decontaminated.

An improved model was constructed which eliminated the e lec t ros ta t ic de­

flector and provided m o r e efficient

pumping of the de tec tor . A new

16-STAGE ELECTRON MULTIPLIER

ADJUSTABLE SLIT TO PREAMP

source vo lume, detector chamber ,

and inlet line were ins ta l led.

E lec t r i ca l leads for

each of the guide r ings of the cone

were brought in through Kovar

seals welded into the back flange.

The voltage on each ring can be

var ied over a wide range by means

of a 10-turn Helipot. A profile

sketch of the naodified spec t ro ­

me te r appears in F ig . 9.

TRAP a 450-5/sec PUMP

60° SECTOR MAGNETIC FIELD -—J

(R= 12 INCHES)

COLD BAFFLE

ADJUSTABLE SLIT

GRIDS-

0 30 CENTIMETERS

IONIZATION GAUGE —

ION GUN

CAPILLARY LEAK

INLET FOR RADIOACTIVE GAS

TRAP a '450 je/sec Hg

PUMP

GUIDE RINGS

30° SOURCE CONE

Fig . 9. Mass spec t rometer for radioactive g a s e s .

S. Wexler , Phys ics Division Summary Report ANL-5786 (July-Sept­ember 1957), pp. 79 -81 .

m - 4 - 1

III. CRYSTALLOGRAPHY

4-1 Crys t a l S t ruc tu re Studies of Compovmds of E lements Ac—Am (5230)

H. A. P le t t inger and W. H. Zacha r i a sen Repor ted by W, H. Zacha r i a sen

THE CRYSTAL STRUCTURE O F SODIUM URANYL ACETATE

Sodium uranyl a c e t a t e , NaU02(02CCH ) , i s cubic with

space group P2 3 and a = 10.688 ± 0.002 A. The posi t ions of a l l a toms

were deduced from p r e c i s e l y m e a s u r e d x - r a y diffraction in t ens i t i e s . In

the coll inear uranyl g roup , U - O = 1.71 ± 0. 04 A. Norma l to the uranyl

axis a r e six secondary bonds from uran ium to ace ta te oxygens with

U - O = 2. 49 ± 0. 02 A. Sodium is bonded to six aceta te oxygens with

Na - O = 2. 37 ± 0 .04 A. The bond lengths within the ace ta te group a r e

C - C = 1.52 ± 0.05 A , C - O = 1.25 ± 0.05 A and 1.28 ± 0.04 A, and

121 is found for the carboxyl bond angle . A rev i sed bond length vs bond VI ~

s t rength curve for U - O bonds is p r e sen t ed .

E a r l i e r s tudies of the c rys t a l s t ruc tu re of uranyl sa l t s have

given some information about the c rys t a l chemis t ry of these compounds. It

has been shown that the uranivim a t o m , in addition to the two strong uranyl

bonds , forms four, five or s ix secondary bonds to oxygen or fluorine a t o m s .

The posi t ions of the light a toms have been de te rmined with p rec i s ion only

for a smal l number of s t r u c t u r e s ; but it was found that the lengths of the

p r i m a r y a s wel l as of the secondary bonds va r i ed considerably from conapound

to compound. This var ia t ion has been co r re l a t ed with corresponding var ia t ion

4-1 19

1 in the bond s t r eng ths . However , the published empi r i ca l bond length vs

bond s t rength curve was based upon a smal l number of observa t ions , and the

p resen t invest igat ion was undertaken in the hope of obtaining further re l iab le

exper imenta l r e s u l t s .

The c rys t a l s t ruc tu re of sodium uranyl ace t a t e , NaU02(02CCH^)g, 2

was f i rs t studied by I. Fankuchen. He repor ted the space group P2^3 and four

molecules in a \init cube with a = 10.670 ± 0.001 kX. Fankuchen descr ibed a complete s t r u c t u r e ; but only the u ran ium and sodivim posit ions were deduced

from the observed in t ens i t i e s . However , this ea r ly work gave the impor tant

r e su l t th,at the uranyl r a d i c a l , by space group s y m m e t r y , had to be co l l inear .

The i s o s t r u c t u r a l neptunium and plutonium compounds were 3

identified during the w a r . A unit cube of a = 10. 659 ± 0. 002 kX was repor ted

for the neptunium and of a = 10.643 + 0.002 kX for the plutonium compound.

The analogous anaer ic ium compound has since been added to the i so s t ruc tu r a l 4

s e r i e s .

EXPERIMENTAL PROCEDURE

5 6

The s t ruc tu re analys is of MgUO O^ and of K UO^F demon­

s t ra ted that it is poss ib le by x - r a y diffraction methods to locate the posit ions

of light a toms in the p r e sence of u ran ium to an accuracy of 0. 03 A. In o rde r

to r e a c h this p rec i s ion i t i s n e c e s s a r y to m e a s u r e in tensi t ies with an accu racy

at tainable only with counters and to c o r r e c t accura te ly for absorpt ion and ex­

tinction effects .

1 W. H. Z a c h a r i a s e n , Acta C rys t . jL2 , 795 (1954).

2

I . Fankuchen, Z . K r i s t a l l o g r . 9i_, 47 3 (1935). 3

W. H. Z a c h a r i a s e n , Acta C rys t . _2, 388 (1949). 4

F . H. E l l i nge r , P r i v a t e commxinication (1956). 5

W. H. Z a c h a r i a s e n , Acta C rys t . jL2 , 788 (1954).

W. H. Z a c h a r i a s e n , Acta C rys t . 12, 783 (1954).

in-4-1

Crys ta l s w e r e p repa red by slow evaporat ion from a solution

of uranyl n i t ra te and sodium ace ta te in mola r p ropor t ions . Most of the c r y ­

s ta ls so obtained w e r e found unsuitable for intensi ty m e a s u r e m e n t s , s ince

the x - r a y showed a seemingly single c rys t a l to consis t of two or m o r e Individ

uals in slight misa l ignment . However , two excellent spec imens w e r e even­

tually found, and these were made into nea r ly perfec t sphe res in the Bond

sphere g r i n d e r . The rad i i of the two spheres w e r e 0.0116 ± 0.0002 cm

and 0.0122 ± 0.0003 c m , where the l imi ts of e r r o r denote the ex t r eme

var ia t ion .

The intensi ty m e a s u r e m e n t s were c a r r i e d out with a Genera l

E l e c t r i c XRD spec t rome te r rebui l t for s ing le -c rys t a l work and using

f i l tered CuK radia t ion and a propor t ional counter . The in tens i t ies of a l l

possible HKO ref lect ions w e r e m e a s u r e d . Because of the very high a b s o r p -_ i

tion ((0. = 470 cm ) , v e r y smal l depa r tu r e s from perfect spher ica l shape

give r i s e to l a rge in tens i ty differences for equivalent re f lec t ions . In ex t reme

cases it was found that the intensi ty could vary by as much as 30% from one

equivalent plane to ano the r , while in tensi ty m e a s u r e m e n t s for a given plane

were reproducib le to 2%. In o rder to min imize this source of e r r o r ,

m e a s u r e m e n t s were made for a l l p lanes of the s a m e crys ta l lographic form

and the average was taken . As a m e a n s of further reducing the expe r imen­

ta l e r r o r s , comple t e HKO data were obtained for both c rys t a l sphe res

desc r ibed above . When the in tens i t ies were reduced to s t r uc tu r e f a c t o r s ,

t he re was n e a r l y perfec t ag reemen t between the two se t s of complete da ta .

THE RESULTS

The complete s t r uc tu r e was deduced in a d i rec t manner with

the aid of the "heavy a tom technique. "

In ag reemen t with Fankuchen ' s e a r l y work , it was found that

ni-4-1 2

a = 10.688 ± 0.002 A with four naolecules per unit cell and space group

P2 3. The posi t ions of this space group a r e :

4 a (x ,x ,x ) ; ( | + x , | - x , x ) ^

12b ( x , y , z ) J ; (f + x , f - y , z ) ^ ; ( | + y , | - z , x ) ^ ;

( i + z i - X, y) ^ .

The u ran ium a t o m s , the sodium a toms and the uranyl oxygen

a toms (O^ and O ) a r e in posi t ions 4a . All the other a toms a r e in the gen­

e r a l posi t ions 12b. The a tomic coordinates a r e as given in Table I„

TABLE I . Atomic coordinates in sodium uranyl ace t a t e .

2 Fankuchen This study

0.4292 ± 0.0003 0.8289 ± 0.0006 0.336 ± 0.002 0.521 ± 0.002 0. 382 +± 0.002 0.291 ± 0.001 0.608 ± 0.001 0.551 ± 0,001 0.241 + 0.001 0.500 ± 0.002 0.482 ± 0,001 0.229 ± 0.002 0.598 ± 0.001 0.509 ± 0.002 0.118 ± 0.002 0.683 + 0,001

u N a

Ol On OTTT

Oiv

Cl

ClI

X

X

X

X

X

y z X

y z X

y z X

y z

0,428 ± 0.002 0.81 ± 0 .03 0 .31 ± 0.02 0.55 +± 0.02

22 i n - 4 - 1

T A B L E n . L e n g t h s of t h e b o n d s f o r m e d by the a t o m s in s o d i u m u r a n y l a c e t a t e .

OT - 1 U = 1 .74 + 0 . 0 4 A u

Na

Cl

- l O i =

- i O n =

- 3 0 i i i =

- 3 0 i v =

- 3 0 i n =

- 3 0 i y =

- I C j i =

1.72 ± 0 . 0 4 A

1.70 + 0 . 0 4 A

2 . 4 7 ± 0 . 0 2 A

2 . 5 1 + 0 . 0 2 A

2 . 3 9 ± 0 . 0 4 A

2 . 3 6 ± 0 . 0 4 A

1 .52 ± 0 . 0 5 A

O l -

On

OTTT

OTV

1 U = 1.70 ± 0 . 0 4 A

- 1 U = 2 . 4 7 ± 0 . 0 2 A

- 1 Na = 2 . 39 ± 0 . 0 3 A

- 1 Cj = 1.26 ± 0 . 0 5 A

- 1 U = 2 . 5 1 ± 0 . 0 2 A

- 1 Ojjj- = 1 . 2 6 ± 0 . 0 5 A - 1 Na = 2 . 3 6 ± 0 . 0 4 A

- 1 O j y = 1 .28 ± 0 . 0 4 A - 1 Cj = 1 .28 ± 0 „ 0 4 A

O m - Ci - O j y « 121°

C j j - 1 C j = 1 .52 ± 0 . 0 5 A

- 1 Hj = 1.1 ( 0 . 8 ) A

- 1 H Q = 1.0 ( 1 . 5 ) A

- 1 H J ^ = 1.0 ( 1 . 1 ) A

The l e n g t h s of t h e b o n d s f o r m e d by t h e v a r i o u s a t o m s i n t h e s t r u c t u r e a r e

g iven in T a b l e 11. T h e c o n f i g u r a t i o n abou t a u r a n i u m a t o m i s shown in

F i g . 1 0 .

III-4-1 I I I - lO- l

F ig . 10. The configuration about a uraniuna atom and within the aceta te g roup , as seen along a three-fold ax i s . The u r a n ­ium atom l ies in the projection plane. Numbers in paren theses give the height in A above this p lane.

This has been repor ted by W. H. Zachar iasen and H. A.

P le t t inger , Acta Crys t . 12, 526-530 (July 1959).

10-1 The Crys ta l St ructure of Li2WO^ (5230)

H. A. Ple t t inger and W. H. Zachar iasen Reported by W. H. Zachar iasen

This compound is rhombohedral with six molecules in

the unit cel l . The dimensions of the rhombohedral unit cell a r e

a = 8.888 ± 0.002 A, a = 107.78 ± 0 . 0 3 ° . The dimensions of the c o r r e s ­

ponding hexagonal cell with 18 molecules a r e a = 14. 361 A, c = 9. 602 A.

A p rec i se determinat ion of a l l atonaic positions is under

way.

24 V -15 -9

V. THEORETICAL PHYSICS, GENERAL

15-9 Sta t i s t ica l P r o p e r t i e s of Nuclear Energy States ( former ly

"Ene rgy -Leve l Densi ty of a System, of F e r m i P a r t i c l e s " ) (5220)

N . Rosenzweig and C. E . P o r t e r Repor ted by N . Rosenzweig

Through the kind cooperat ion of D . R. Ing l i s , the following

paper was p resen ted at the Honolulu naeeting of the Amer ican Phys ica l

Society, August , 1959.'^

STATISTICAL PROPERTIES OF ATOMIC ENERGY STATES

Ever since the d i scovery of the phenomenon of neutron r e ­

sonance and i t s explanation in t e r m s of the "quas i - s t a t iona ry" s ta tes of the

compound nuc leus , a t t empts have been made to d iscover the s ta t i s t i ca l

p r o p e r t i e s of these s t a t e s .

One p roper ty of i n t e r e s t i s the dis t r ibut ion of the spacing

between adjacent l e v e l s , about which we have lea rned quite a bit during the

l a s t two y e a r s . The exper imenta l f ac t s , a s obtained in the resonance sca t ­

te r ing of slow^ n e u t r o n s , s eem to point to the following genera l ru l e s (F ig . 11).

I , The spacing between adjacent levels having the same spin

and pa r i ty i s d is t r ibuted ( re la t ive to the mean spacing) according to a f r e ­

quency function which is given to a good approximation by the Wigner dis t r ibut ion

Univers i ty of Minnesota .

N . Rosenzweig and C. E . P o r t e r , Bul l . A m . P h y s . S o c , S e r . I I , 4 ,

353 (1959).

v-15-9 25

-TT 2

P (x) = -5- xe 4

where x = spac ing/mean spacing. The most charac te r i s t i c feature of this

distr ibution is that the probabil i ty of a ze ro spacing van ishes , i . e . , neigh­

boring levels " repe l" each other . This should be compared with what one

gets on the bas i s of the naive and

inco r rec t supposition that the levels

occur in a completely random way.

The la t te r assumption leads to an

exponential , which has i t s g rea te s t

value at X = 0.

2. The second par t

of the rule s ta tes that levels of

different spin or par i ty a r e not

in any way cor re la ted with each

othe r .

This has the conse­

quence that for a set of levels which

is a superposit ion of different spin

s y s t e m s , the resul t ing spacing d i s ­

tr ibution has a cha rac te r which is

in te rmedia te between the Wigner

distr ibution and the exponential

dis t r ibut ion. For example , the

broken line in F ig . 12 gives the

calculated resu l t for the random

superposit ion of two spin sys tems

which have the same naean spacing.

The distr ibution is finite at the

nvAdsxNi UNO /Ainisvaodd Fig . 11. Theoret ica l distr ibution

of spacings. The dashed curve r ep re sen t s the resu l t of super ­posing two spin sys tems having the same mean spacing.

origin and has a peaik which is l e s s

v - 1 5 - 9

F ig . 12. Distr ibution of spacings for the odd atomic levels of Os I from 37 000 to 55 000 cm""^.

pronounced than that of the Wigner

dis t r ibut ion. In the l imit of super ­

posing, at r andom, a la rge number

of different spin s y s t e m s , neighbor­

ing levels evidently tend to become

completely uncorre la ted and the

exponential distr ibution will be

approached.

The preceding r e ­

m a r k s were in the nature of an in­

troduct ion. We now come to that

which is new.

We have found that the same s ta t is t ica l r u l e s , which were

first d i scussed in nuclear phys ic s , hold for the spec t ra of many complex

a toms . (Incidentally, the relevant exper imental m a t e r i a l in the atomic

domain is about 100 t imes as abundant as that available in nuclear phys ic s ,

and sonae of it i s many yea r s old.)

One expects that the above phenomenon is cha rac te r i s t i c

of the "complex" spec t ra a r i s ing from the interact ion of many e lec t rons .

On the other hand, the only spec t ra which a re useful for exhibiting the r e ­

pulsion phenonaenon a r e those in which re la t ively few levels have been

mi s sed by the atomic spec t roscop i s t s . It seenas that both requ i rements

a re fulfilled in the regions of the periodic table in which the outermost

s and d orbi ts compete energet ical ly in the formation of the ground state

and the low-lying excited s t a t e s . This r e su l t s in the par t icu la r ly r ich —

and in many cases thoroughly ana lyzed—struc ture of odd-par i ty levels n n - 1

which a r i s e naainly from the overlapping configurations d p and d s p .

In F ig . 12 we g ive , as a typical example , the distr ibution

of the spacing, in the form of a h i s tog ram, for the odd levels of neut ra l

osmium. It should be c lear ly understood that the distr ibution of spacing

was obtained separa te ly for each set of levels having the same J. The

v-15-9 27

r e su l t s were then combined m e r e l y

to reduce the s ta t i s t ica l fluctuations.

The repulsion phenomenon is quite

evident.

When the levels

of osnaium a re not separa ted a c ­

cording to J va lues , the repuls ion

of levels should la rgely d isappear .

This is shown in F ig . 13.

The e lements

of the i ron group give us an

opportunity to see the same phe«

nomenon when the Hamiltonian is

vir tual ly independent of the spin.

In this region of the per iodic t ab le ,

Russe l -Saunders coupling holds

to a fairly good approximation. We

may therefore infer what the pos i ­

tions of the energy levels would be

in the absence of spin-orbi t coup­

l ing, by computing the "center of

gravi ty" of each mult iplet . In

that case par i ty , S, and L a r e con­

stants of the motion.

nvAaaiNi imn/ Ainiavaoad Fig . 13. Distribution of spacings

for the odd-pari ty levels of Os I. The exponential d i s t r i ­bution is approached when the levels a re not separated accord­ing to J va lues .

As a typical example we show the distr ibution between

the cen te rs of gravity of the odd mult iplets of neutral i ron (Fig. 14). We

see that the levels having the same S and L values do indeed repel each

other . Again the repulsion is grea t ly reduced if the levels a re not sepa r ­

ated according to symmet ry c h a r a c t e r , as is shown in F ig . 15.

The above re su l t s a re fairly typical of some twenty

v - 1 5 - 9

I 2 SPACING

Fig, 14. Distr ibution of spacings for the odd t r ip le t s and quintets of F e l (41 spacings) .

F ig . 15. Distr ibution of spacings for the odd t e r m s of F e l . The exponential distr ibution is a p ­proached when the levels a r e not separa ted according to S and L va lues .

F ig . 16. Distr ibution of spacings based on spect ra for severa l elenaents. F e l odd t r ip le t s and quinte ts , (30 spacings); F e l l odd doublets and quar te ts (21 spacings); T i l odd singlets and t r ip le t s (50 spacings); O s l odd levels with J = 1, 2, 3 , 4 , 5 , 6 (145 spacings) .

a tomic spect ra which we have examined to da te . It is na tura l to suppose

(and supporting theore t ica l a rguments can be given) that the distr ibution

of spacing observed for each element ref lects the saunae underlying d i s ­

t r ibut ion. We have therefore combined (Fig. 16) the r e su l t s for severa l

atonaic spec t ra in order to see the underlying distr ibution with improved

s ta t i s t ica l accu racy .

These empir ica l r e s u l t s , together with those obtained

in nuclear phys ic s , cer ta inly support the idea that neighboring levels of

the sanae symmet ry charac te r repe l each other according to a definite

s ta t i s t ica l law (which is given to a good approximation by the Wigner d i s ­

t r ibut ion) , and that the phenomenon is a genera l p roper ty of al l sufficiently

complex quantum s y s t e m s .

V-18-4 3^

18-4 Elenaentary P a r t i c l e s in DeSit ter Space (formerly " P a r a ­

m e t r i c Formula t ion of Quantum Mechanics") (5220)

Will iam C. Davidon

In the ini t ial work which had been done on this pro jec t , the under ­

lying s y m m e t r y a sc r ibed to space - t ime was that of the usual Lorentz group , and

the additional coordinate introduced was in te rpre ted solely as a pa r ame te r to

facili tate the re la t iv i s t i c desc r ip t ion . However , it i s a lso possible to modify

the bas i c s y m m e t r y a s s u m p t i o n s , in which case the additional coordinate is

no longer purely a p a r a m e t e r , but plays a m o r e essen t ia l r o l e .

The re a r e s eve ra l r e a s o n s for considering such a modification of

space - t ime s y m m e t r i e s . One is that the determinat ion of the actual symmet ry

group of space - t ime can not be made a p r i o r i , but mus t be chosen to bes t d e s ­

cribe r ea l i t y . Fo r this r e a s o n , one can not conclude that actual space - t ime

exactly p o s s e s s e s the s y m m e t r y of the Lorentz group , but only that this

assumpt ion has been well confirmed. Small modifications of th is assumption

can st i l l be m a d e , however , without contradicting exper ience . Though these

modifications a r e s m a l l , they may st i l l have cer ta in qualitative consequences .

As an example , the exis tence of an t i pa r t i c l e s , and the connection between

spin and s ta t i s t i c s a r e usual ly der ived from the Lorentz group independently

of the nunaerical value for the veloci ty of light. Hence when we consider

modifications of the Lorentz g roup , the possibi l i ty that some implicat ions

will be of significance can not be excluded on the bas i s of the " s m a l l n e s s "

of the modificat ion.

A second r ea son for considering a modification to the Lorentz

group is to obtain a na tu ra l way of introducing a fundamental length which is

bas i c to a l l physical t h e o r i e s , a s the Lorentz group int roduces a fundamental

veloci ty. The fundamental length so introduced is a ve ry la rge one instead of

v - 1 8 - 4

the m o r e usual length of nuclear d imensions used a s a cut-off in field

theore t ica l ca lcula t ions . With a fundamental length and velocity d e t e r ­

mined by the synametry g roup , and with P l a n c k ' s constant connecting the

gene ra to r s of the s y m m e t r y group with o b s e r v a b l e s , a l l d imensions a r e

de te rmined .

The re i s a th i rd motivation for these considera t ions of a m o r e

methodological c h a r a c t e r . That is to dist inguish the consequences of sym­

m e t r y assumpt ions m o r e unambiguously. In o rde r to a s s e s s the effects

of any one factor in a given s i tuat ion, it i s valuable to consider var ia t ions

in that factor while everything e lse i s held constant , even if these var ia t ions

a r e only cons idered to be v i r t ua l . H e r e , by considering the effects of

modifications in a s y m m e t r y group differing slightly from the Lorentz group ,

a m o r e thorough understanding of the Lorentz group i tself i s obtained.

The na tu re of the modification being examined is to rep lace the

Lorentz group by the DeSit ter g roup , which cons is t s of a l l l e n g t h - p r e s e r v ­

ing mappings in a s p a c e - t i m e of constant c u r v a t u r e . The Lorentz group is

a l imiting case of the DeSit ter group as the curva ture goes to z e r o , just as

the Gali lei group is a l imiting case of the Lorentz group as the velocity of

light beconaes infinite. F o r nonvanishing c u r v a t u r e , the homogenous Lorentz

t r ans fo rmat ions r ema in a subgroup of the full s y m m e t r y g roup , but the cona-

mutation re la t ions among the g e n e r a t o r s of t r ans la t ions no longer vanish .

This effect can be v isual ized by considering the l eng th -prese rv ing mappings

of objects on the surface of a sphe re . In o rde r to d isplace the objects in the

neighborhood of one point on the sphere while keeping al l d i s tances unchanged,

it i s n e c e s s a r y to ro ta te a l l the objects about an axis one quadrant away from

the point in quest ion. The poss ible motions as viewed in the neighborhood of

any point consis t of two perpendicular t r ans la t ions and one rotat ion; but , a s

8-4

V-41-2

31

viewed on the sphere a s a whole , these a r e th ree ro ta t ions . In this c a s e ,

the commutator between the two t rans la t ions i s equal to the rotat ion opera tor

divided by the square of the rad ius of c u r v a t u r e , and this re la t ionship gene ra l ­

i z e s readi ly to the commutator for d isp lacements in a curved space- t ime of

constant cu rva tu r e .

At the p resen t t i m e , effort i s being focused on the full physical

in te rpre ta t ion of the r ep resen ta t ion of this group. In p a r t i c u l a r , the defini­

tion of local quanti t ies and the significance of charge a r e being developed.

41-2 Solvable F ie ld Theor ies (5230)

H. Eks te in

A paper enti t led "Equivalent Hamiltonians in Scattering Theory"

has been p r epa red for publicat ion. This paper is a contribution to discuss ion

of the question: to what extent does the scat ter ing m a t r i x de te rmine the

Hamil tonian? The Hamil tonians considered a r e nonre la t iv i s t i c , but in ex­

tension of previous s tud ie s , "non- loca l" potentials and many-body potentials

a r e al lowed. A la rge c l a s s of un i ta ry t ransformat ions i s found which p r o ­

duce Hamil tonians leading to the same S-mat r ix . In the las t sect ion, it i s

shown that th is equivalence is only a special consequence of the genera l

axionaatic formulation of sca t te r ing in field theory .

In the course of thinking about solvable field t h e o r i e s , it

o ccu r r ed to me tha t , ins tead of formulating the problem in t e r m s of the

usua l "basic f ie lds" which have no c lear physical s ignif icance, one should

r a the r s t a r t with the physical pa r t i c l e - c r ea t ion o p e r a t o r s . T h i s , however ,

r e q u i r e s a reformula t ion of the axioms of field theory . The presen t paper

V-41-2 V 45-13

contains this reformula t ion in Sec. IV. The f i rs t t h r ee sect ions a r e appl i ­

cations of the proposed axioms to an old p r o b l e m , and may be considered as

accidental b y - p r o d u c t s .

45-13 Meson-Nucleon Interact ion (5230)

K. Tanaka

1 In a previous r epo r t the pro ton-neut ron m a s s difference was

exanained by a method which in t roduces a complete set of in te rmedia te

s t a t e s . This naethod of evaluating the pro ton-neutron m a s s difference has been

extended to the calculation of pa r t of the contribution to the se l f -mass of m e s o n s .

The effect of nucleon-ant inucleon p a i r s around the meson (IT and K) has been

taken into account by introducing a form factor for the charge dis t r ibut ion of the

naeson. This form fac tor , which en te r s in a na tura l way , i s cha rac t e r i zed

by a r m s r a d i u s .

When one a s s u m e s a Yukawa model for the meson form factor ,

one can explain the m a s s difference between charged and neu t ra l K-mesons _ 1 3

if the charge dis t r ibut ion has a r m s radius of a = 0.48 X 10 c m , a r e a s o n -

able va lue . With the same Yukawa mode l , one can obtain the c o r r e c t sign but

not the c o r r e c t naagnitude of the m a s s difference between charged and neut ra l

TT-xnesons.

ANL Phys ic s Division Summary Repor t , ANL-5955 (December 1958 —

January 1959), p . 45 .

33

PUBLICATIONS SINCE THE LAST REPORT

PAPERS

^He-^H - STRAHLUNGSALTER EINES STEINMETEORITEN

F , Begemann , P . E b e r h a r d t (U. of Chicago), and

Z . Na tur forsch . 14a, 500-503 (May-June 1959).

MASS SPECTROMETRIC STUDY OF THE SUBLIMATION OF LITHIUM OXIDE

Joseph Berkowi tz , Williana A. Chupka, Gary D, Blue, and John L . Marg rave (U. of Wisconsin) . . . . , „ . . (Project 11-29).

J . P h y s . Chem. 6^, 644-648 (April 1959).

DYNAMIC-CONDENSER MAGNETIC FLUXMETER

S. B . Bur son , D. W. Mar t in , and L , C. Schmid. . . . (Project 1-149) Rev . Sci . I n s t r . 30, 513-521 (July 1959).

2 4 0 2 4 2 2 4 3

SLOW-NEUTRON CROSS SECTIONS OF Pu , Pu and Am

R. E . Co te ' , L„ M. Bol l inger , R. F . B a r n e s , and H. Diamond (Project 1-3)

P h y s . Rev . 114, 505-509 (April 15, 1959),

CLOUD-CHAMBER MEASUREMENT OF THE HALF-LIFE OF THE NEUTRON

P h y s . Rev. 114, 285-292 (April 1, 1959).

VARIABLE METRIC METHOD OF IvIINIMIZATION

Williana C. Davidon. . . . . . . . < > . . . . , , , . . . . (Project V-17) Topical Repor t ANL-5990 (May 1959).

POLARIZATION MEASUREMENTS ON NUCLEAR GAMMA RAYS

Lawrence W, Fagg (Naval R e s e a r c h Lab . ) and Stanley S. Hanna „

R e v s . Modern P h y s . 3i^, 711-758 (July 1959),

DISTRIBUTION OF T ^ ANGULAR MOMENTA, LEVEL SPACINGS AND NEU­TRON WIDTHS OF Al ^

Car l T . Hibdon, <,. . , < , , . . . . . . (Projec t 1-98) P h y s . Rev. 114, 179-194 (April 1, 1959).

40 LIFETIME OF THE FIRST EXCITED STATE OF K

F . J . Lynch and R. E . Holland. (Projec t 1-14) P h y s . Rev . 114, 825-826 (May 1, 1959).

PRECISION INTEGRATOR FOR ION BEAMS

F r a n k J . Lynch and Alexander Langsdorf, J r (Pro jec t 1-12) Rev . Sci . I n s t r . 30, 276-279 (April 1959).

COLLECTIVE AND INTERPARTICLE INTERACTIONS IN EVEN-EVEN NUCLEI

B . J a m e s Raz , (Pro jec t V-5) P h y s . Rev . 114, 1116-1123 (May 15, 1?59).

A SCINTILLATION SPECTROMETER WITH AN ANTICOINCIDENCE ANNULUS OF Na l (T l ) .

C. C. T r a i l and Sol Raboy. . . (Project 1-55) Rev . Sci . I n s t r . 30, 425-429 (Jvme 1959).

DISSOCIATION OF TH AND 1^ BY P- DECAY

Sol Wexle r . „ (Pro jec t n - 3 8 ) J . Inorg . Nucl . Chem. JJO, 8-16 (April 1959).

ELASTIC SCATTERING OF 21 .6-MEV DEUTERONS BY SEPARATED ISO­TOPES O F NICKEL AND COPPER

J . L . Yntema. (Pro jec t 1-22) P h y s . Rev . 114, 820-822 (May 1, 1959).

INELASTIC SCATTERING OF 21 .6-MEV DEUTERONS

J , L . Yntema and B . Zeldman , . . „ . , . . (Pro jec t 1-22) P h y s . Rev . 114, 815-820 (May 1, 1959).

CRYSTAL CHEMICAL STUDIES OF THE 5f-SERIES OF ELEMENTS, XXV THE CRYSTAL STRUCTURE OF SODIUM URANYL ACETATE

W. H. Zacha r i a sen and H. A. P le t t inger , . . . . . . . (Pro jec t III-5) Acta C r y s t . 12, 526-530 (July 1959).

35

ABSTRACTS

STATISTICAL PROPERTIES OF ATOMIC SPECTRA

N. Rosenzweig and C. E . P o r t e r (U. of Minnesota) . . (Project V-15) Bull . Am. P h y s . S o c , Se r . I I , 4 , 353 (Aug. 27, 1959).

ADDITIONAL PAPERS ACCEPTED FOR PUBLICATION

1 1 3 1 1 3 m THE DECAY OF 5^Sn (112 d) AND ^gln (1 ,73 hr)

S. B . Bur son , H. A. Grench , and L . C. S c h m i d . . . . (Project 1-37) P h y s . Rev.

THE Mu MESON AND THE CATALYSIS OF NUCLEAR REACTIONS

N, D'Angelo , A m . J . P h y s .

WAVE OPERATORS IN MULTICHANNEL SCATTERING

Melvin N. Hack (Project V-27) Nuovo Cimento

A NOMOGRAPH FOR TIME-OF-FLIGHT MEASUREMENTS OF FAST NEUTRONS

R. E . Holland (Projec t 1-14) Rev . Sci . I n s t r .

NUCLEAR RESONANCE ABSORPTION OF GAMMA RAYS AT LOW TEMPERATURES

L . L . L e e , J r . , L. Meyer -Sch i i t zmeis te r , J . P . Schiffer, and D. Vincent . . . ( P r o j e c t 1-19)

P h y s . Rev. L e t t e r s .

ANALYSIS OF ANGULAR DISTRIBUTIONS IN THE REACTION B ^(a,p)C

L . L. L e e , J r . , and J . P . Schiffer (Project 1-25) P h y s . Rev .

SINGLE-PARTICLE STATES OF THE NEUTRON FROM GROSS STRUCTURE IN THE PROTON SPECTRA OF (d,p) REACTIONS

J, P . Schiffer, L . L . L e e , J r . , and B . Z e l d m a n . . . . (Project 1-29) P h y s . Rev .

THE DECAY OF ^^Nd (12 min)

L. C. Schmid and S. B . B u r s o n . . . . (Project 1-34) P h y s . Rev .

THE DECAY OF ^ ,Sm ^^ (23.5 min)

L . C. Schmid and S. B . Burson (Project 1-38) P h y s . Rev .

THE DECAY OF g4Gd^^^(3.7 3 min)

L. C. Sclimid, S. B . B u r s o n , and J . M. Cork(U. of Michigan) (Projec t 1-36)

PROTON-NEUTRON MASS DIFFERENCE

Sigenobu Sunakawa and Katsumi Tanaka (Projec t V-45) P h y s . Rev .

A NEW METHOD FOR GRAPHICAL REPRODUCTION O F CATHODE-RAY OSaLLOGRAMS

Rober t K. Swank and Eugene A. Mroz (Projec t 1-144) Rev. Sc i . I n s t r .

PERSONNEL CHANGES IN THE ANL PHYSICS DIVISION

NEW MEMBERS O F THE DIVISION

Resident R e s e a r c h Assoc ia tes

D r . J . P . E l l io t t , Univers i ty of Southampton, England. P rob lems in the

theory of nuclear s t r u c t u r e . (Host: D. R. Ingl is . )

D r . C. S. Lit t le John. Nuclear resonance f luorescence in solids at low

t e m p e r a t u r e s ; polar izat ion of protons in (d,p) r eac t ions .

(Host: J . P . Schiffer .)

Consultants

D r . Steven A Moszkowski , Univers i ty of the City of Los Angeles . Nuclear

naany-body p rob lem. (Host: D. R. Ingl i s . )

D r . Ben Mottelson, Insti tute for Theore t i ca l P h y s i c s , Copenhagen, Den­

m a r k . Theory of nuclear s t r u c t u r e . (Host: D, R. Ingl i s . )

Resident Student Associa te

M r . Huzihiro A r a k i , graduate s tudent , Pr ince ton Univers i ty . Working

with H. Eks te in in field theory . Came to Argonne on July 16,

1959.

Student Aide (Sumnaer)

M r . Neal Cason , Ripon College. Working with D. C. Hess on improvement

in m a s s spectronaeter MA-16A.

Technicians

Mr . Char le s P e r k o , J r . Joined the Phys i c s Division as a r e s e a r c h techni­

cian with S. Wexler on June 22, 1959.

M r . John J . Vronich. Joined the Phys i c s Division a s a r e s e a r c h technician

with L. M. Bol l inger on July 7 , 1959.

S e c r e t a r y

M r s . Lo r r a ine M. B e r e s . Joined the Phys i c s Division on August 10, 1959

a s s e c r e t a r y in the theore t i ca l physics wing.

DEPARTURES

D r . Nicola D'Angelo joined the Phys ic s Division a s a Resident R e s e a r c h

Assoc ia te on October 19, 1956. He has col laborated with C.

M. Huddle ston on the m e a s u r e m e n t of the half-life of the neu­

t ron by use of a diffusion cloud chanaber (Pro jec t 1-117) and,

m o r e r ecen t ly , with L, M. Bollinger on the half - l ives of 5 6

excited s t a tes of Mn (Pro jec t 1-9), He t e rmina ted a t ANL

on August 10, 1959 to go to Pr ince ton Univers i ty , P r ince ton ,

New J e r s e y .

D r . Lee J . Kieffer joined the Phys i c s Division as a Resident R e s e a r c h

Assoc ia te on Novenaber 1 1 , 1957, He has col laborated with

L. S. Goodnaan on m e a s u r e m e n t s of nuclear spins and m o m ­

ents (Pro jec t 1-80). He t e rmina t ed at ANL on July 9 , 1959

to go to Aeroneut ronic S y s t e m s , Inc . , Box 697, Newport

Beach , Cal i fornia .

Leaves of Absence

D r . H. Eks te in left ANL on August 27, 1959 for a y e a r ' s leave of absence .

He will spend mos t of the year with D r . Abdus Salam at the

Mathemat ics Depar tmen t , Imper ia l College, Exhibition Road,

South Kensington, London, S. W, 1 but will spend one month

with R. Haag in M a r s e i l l e s and another month with L . van Hove

in Utrecht . He plans to continue study on solvable problems in

field theory and to begin work in h igh-energy physics and d i s ­

pe r s ion r e l a t ions . He expects to r e t u r n to Argonne on Septem­

ber 1, I960.

D r . Alexander Langsdorf , J r . left ANL on June 26, 1959 for a y e a r ' s leave

of absence for r e s e a r c h at the Atomic Energy R e s e a r c h E s t ­

ab l i shmen t , Harwe l l , B e r k s , England. He plans to do neutron

c r o s s - s e c t i o n work with the i r l inear a c c e l e r a t o r . He expects

to r e tu rn to Argonne in June i960 .

D r . Linwood L . L e e , J r . left ANL on August 25 , 1959 for a y e a r ' s leave

of absence a s Visiting Ass i s t an t P ro fe s so r at the Universi ty of

Minnesota , Minneapol i s , Minnesota^ He expects to r e tu rn to

Argonne in the s u m m e r of I960.

D r . John P . Schiffer left ANL on July 31 , 1959 for a y e a r ' s leave of a b ­

sence on a Guggenheim Fel lowship . He plans to work with

D r . E . P a u l of the Atomic Energy R e s e a r c h Es tab l i shmen t ,

Harwe l l , B e r k s , England and with Dr . W. K. Jentschke of

the Phys ika l i sches S taa ts ins t i tu t , Hamburg , West Germany ,

He will study the ave rage p rope r t i e s of nuc lear levels and

nuc lear r eac t ions by use of the new tandem Van de Graa.ff

a c c e l e r a t o r at Harwel l and the Van de Graaff at Hamburgh He

plans to r e t u r n to Argonne in August , I960.