NOT FOR PUBLICATION EANDC-47 "U"

EUROPEAN-AMERICAN NUCLEAR DATA COMMITTEE

TECHNICAL MINUTES OF THE EIGHTH MEETING OF THE COMMITTEE

held a t Los Alamos, May 17th-21st, 1965

Compiled by

R. Batchelor , AWRE, Aldermaston

(Executive Secre ta ry)

Aided by

H.T. Motz (LASL)

(Local Secre ta ry)

EANDC S e c r e t a r i a t

European Nuclear Energy Agency, O.E.C.D. 38, Boulevard Suchet , P a r i s 16e

55000 December 1965

Preface to the Technical Minutes

EANDC-47 "U"

This version of the minutes of the eighth meeting

of the European-American Nuclear Data Committee is produced

for general distribution to 'chose concerrhed with measurement

programmes in the nuclear data field. The conclusions are,

however, of an interim nature in many cases, and the document

is therefore marked "Not for Publication" and should neither

be quoted in publications nor listed by abstract journals.

TABLE OF CORTENTS

Table of Contents

L i s t of Members

In t roduc t ion

1. R a t i f i c a t i o n of Procedure f o r Quoting L Documents i n CINDA

2. 2 (a ) New F a c i l i t i e s

2(b) Progress Reports

2 (c ) Considerat ion of the Various Research Papers

2(d) Report of t h e Sub-Committee on Standards

2 (e ) Round Table Conference on Prec i s ion Chemical Analysis

3. Data Indexing, Compiling and Evaluat ing

3 (a ) IAEA A c t i v i t y

3(b) Remarks on Evaluat ion and Multi- Group Cross Sect ions

4. Conf erences

4 ( a ) EANDC-Sponsored Conference on t h e Study of Nuclear S t ruc tu re with Neutrons

4 (b) Round Table Conference on Mass Spectrometry and Counting Techniques

4 (c ) Harwell Seminar on Making of I so top ic Targets

4(d) High I n t e n s i t y Neutron Sources

4 ( e ) Neutron Cross-Section Technology

EBNDC-47 "U"

5. Request Lists

5(a) p~~~~ Fission Cross Section at 2200 m/sec

5(b) Inelastic Scattering

6. Production of Beryllium Single Crystals

Note on Topical Discussion

APPENDIX 'l : List of General Documents

APF'ENDIX 2 : List of Canadian Documents

APPENDIX 3 : List of Euratom Documents

APPENDIX 4 : List of Documents from Other OECD Countries

APPENDIX 5 : List of United Kingdom Documents

APPENDIX 6 : List of United States Documents

aPPENDIX 7 : List of Reports and Publications from Turkey

APPENDIX 8 : Recommended Values for Fissile Isotopes

APPENDIX 9 : Remarks on the use at LASL of Libraries of Evaluated Neutron Interaction Data

APPENDIX 10: Table of First Category Items from the Gee1 Activity Report

iii

EANDC-47 "U"

MINUTES OF THE EIGHTH MEETING OF ZUiC

held i n

LOS; Al-os, U5A, 17th t o 21 st May, 1965

There were present:

E. Bretscher, AERE, Harwell, UK (Chairman)

B. Batchelor, AWRE, Aldermaston, UK (Executive Secretary)

K. H. B e c W t s , Karlsruhe, Federal Republic of Germany

H. Goldstein, Columbia University, USA (Corresponding secretary)

G. C. Hanna, bECL, Chalk River, Canada

W. W. Havens, Columbia University, USA

R. Joly, CEA, Saclay, France

G. 8. Kolstad, USEC, Washington, U S

M. N&ve de M6vergniesY Mol, Belgium

H. B. Smets, ENEA, Par i s

S. Spaepen, Euratom, Geel, Belgium

N. S t a r f e l t , Sweden,

J. S. Story, AEE Winfrith, UK

R. F. Taschek, LASL, USA

P. Weinuierl, Seibersdorf', Austria

Observers:

D r , J.L. Crandal l , EACRP, Savannah River Laboratory, USA

D r . R. Lazarus, LASL

Prof. R. ftakasirna, J A E R I , Japan

D r . C.R. l e s c o t t , Vienna

Looal Secretary:

Dr . H. T, Mota, LASL

INTRODUCTION

D r . Bradbury, Director of Los Alamos Sc ien t i f ic Laboratory, welcomed

members of FANDC t o Los Alamos f o r the eighth meeting of the Committee.

The Chairman welcomed Prof. Nakasima and D r . Crandal l and the

Local Secre ta ry and in t roduced them t o the Committee Members.

l. RATIFICATION OF PROCEDURE FOR 9UOTING L DOCUMENTS I N C I N D A

Goldstein s a id t h a t although the CINDB l i s t i n g s were planned t o be

U documents he wished t o include references t o measursments mentioned

i n L documents, e.g, progress reports, in the listiws, Although

experimenters would probably be re luctant t o re lease numerical values he

f e l t t h a t they would be agreeable t o having t h e i r names and t i t l e s of

L c l a s s reports and ex t r ac t s quoted i n CINDA,

Anyone wishing t o use o r quote L c lass information would s t i l l have

t o seekthe au thoros permission, ( ~ a s c h e k pointed out t h a t it would be

more appropriate t o use the words issuing organisat ionus permission s ince

t he da ta did not usual ly belong t o t he author).

After fur the^ discussion during which it was suggested t h a t S c l a s s

documents should be t r ea t ed i n the same way from the point of view of

CINDB, the EANDC agreed t o the following proposal:- "That L and S class

documents be entered i n to CINDA provided no numerical r e s u l t s a r e

contained i n the entry"

Smets pointed out t h a t a s imilar problem e x i s t s f o r da ta compilation

and obtained the agreement of the EANDC t o t h e f o l l o d n g proposal. "That

nuclear data presented i n EANDC c l a s s L or S documents may be put on d a t a

t a p e s prepared by the ENEA and USA compila t ion cen t r e s only if the au thor

(o r i s s u i n g o rgan i sa t i on ) of t he document agrees , and wi th t he p rov i s ion

t h a t such d a t a can be removed from the tape a t the reques t of the au thor

( o r i s s u i n g o rgan i sa t i on ) . The Centres w i l l consu l t t he au thors i n t h e i r

respective regions".

2.

2(a) New f a c t l i t i e s

Bretscher opened the discussion w:th some d e t a i l s of new f a c i l i t i e s

in the UK, He said t h a t a Tandem machine was now i n operation a t Oxford

University and that eventually it was hoped t o couple it t o a s ingle ended

Van de Graaff b u i l t by NIRNS. It was expected t h a t t he complete f a c i l i t y

would give an output energy f o r singly charged ions of g rea te r than

20 MeV. The 440 MeV Linac a t Glasgow University would probably be brought

i n t o operation l a t e r t h i s year, Harwell i s considering the modification

of i t s cyclotron t o give an order of magnitude increase i n current and

some neutron da ta measurements a r e planned with t h i s machine,

Eatchelor sa id t h a t a klystron bunching system had been incorporated

i n t o the terminal of the AlRRF 6 MV Van de Gm&. Mean pulsed currents

of about 40 pamp had been obtained a t a repe t i t ion r a t e of 5 ~ J s e c , the

pulse width being about I I ~ nsec.

Spaepen. During acceptance t e s t s on the Gee1 l i m e last December some

leaks had appeared arbi BCMN had requested t h a t more development work be ..

car r ied out. It w a s hoped t o carry out f i n a l acceptance t e s t s soon.

Meanwhile the e ight f l i g h t paths (one of 400 m) plus associated equipments

had been ins ta l led .

Beckurts reported t h a t there had been t rouble with the IBIS nachine

a t Karlsnthe; the beam had showed 2 and $0 Mc/sec components i n addit ion

t o t he expected 1 Mc/sec component, The trouble bad now been cured,

The bunching system f o r the 50 MeV cyclotron had been proved t o be

sa t i s fac tory and it was expected t h a t the neutron production would be

9 4 10 i n a 40-' sec burs t a t a r epe t i t i on r a t e of l 0 /sec, It was intended

t o use the f a c i l i t y f o r measurements of aTOT using a f l i g h t path of 50 m,

which may eventually be increased, and a l so U and urn by methods nP

involving the detection of the protons and a-part icles, respectively.

A detect ion system capable of discriminating between proton and a-part icles

had been developed, The Ju l ich laboratory had ordered a 150 MeV

isochronous cyclotron f o r nuclear s t ruc ture studies,

U. A t h i r d sect ion has been added t o the Saclay electron l inac ,

giving an output of 200 mA a t 45 MeV and an increase i n neutron in t ens i t y

of about a f ac to r 3. A 600 MeV l i n a c f o r meson and

photonual.earwork i s being b u i l t a t Saclay. A Mobley compression magnet

had been made f o r use with t he 5 MV Van de Gmaff' a t Cadarache,

Hanna expected the Chalk River MP Tandem ins t a l l a t i on t o keep t o

schedule and t o give beams next year, A new chopper fo r capture y-ray

work would be in s t a l l ed a t the NRU reactor l a t e this year and the scat ter-

ing law programme w i L l soon be brought t o an end, Chalk River i s act ively

engaged on the eonsidesation of an intense neutron generator project using

a sepa ra t ed o r b i t cyclotron. (This provoked some d iscuss ion on the r e l a -

t i v e mer i t s of SOC's and l i n e a r machines f o r producing i n t e n s e neutron

sources ; Taschek thought t h a t t he advantages of the SOC over a l i n a c a t

low cu r ren t disappear a t h igh c u r r e n t s ) . Hanna s a i d t h a t t h e Univers i ty of

Toronto is acqu i r ing a l i n a c which i s expected t o give 2.5 amps a t 35 MeV.

Kolstad drew the a t ten t ion of the EAM)G t o the new l i s t of USA

f a c i l i t i e s in E A N D c ( u s ) ~ ; ~ ~ ,

Havens said t ha t a design study was i n progress t o increase the c w r e n t

from the Columbia cyclotron, hopefully by an order of magnitude,

Taschek sa id t ha t m output energy of 25 MeV f o r singly charged ions

had been obtained w%th the LASL Van de Graaff f a c i l i t y , The current

avai lable a t 20 MeV i s 2 m p but it falls off a s the energy is Lac-ceased.

It had been proved possible t o measure data in the energy range about

10 eV t o 15 YeV with an underg~ound n u c l e a ~ explosion as the neutron source

and there w i l l be further applioation of the method during the summer.

Bretseher suggested t h a t t h i s method might be very useful f o r measuring

cross-sections of the f issaon products.

Crandall said t ha t t he high f l u x reactor a t Savannah River is being

used t o honour many isotope requests, The loadings a r e made in a f l u x

2 of 5 X 1015 ./cm sec , and t h e i r r a d i a t i o n s l a s t f o r 1 week i n an

2 average f l u x of 2 X 1015 ,/cm sec. The r e a c t i v i t y h i s t o r y i n d i c a t e d

no unknown poisons.

4.

Smets sa id t h a t a new mass spectrometer had been acquired i n Norway

and t h a t a Tandem Van de Graaff was working successfully i n S i t z e r l a n d .

Nakasima d i s t r ibu ted a paper describing Japanese f a c i l i t i e s ( t o be

given an EANDC document number*). I n answer t o a question from Kolstad,

Nakasima sa id t h a t Japan was not able t o make separated isotopes in

suf f ic ien t quant i t ies f o r neutron data measurements,

2(b) Progress Reports

The Chairman inv i ted dAsoussion on points of par t i cu la r i n t e r e s t i n

the progress reports ,

In reply t o a question by Nzve, Hanna promised t o invest igate whether

J, P. But ler and D, C, Smkry intend t o measure the I n (n ,n2)In 215m in

the energy region threshold t o 2 MeV,

m Csmmunit~

Spaepen agreed t o supp3y Taschek with fu r the r d e t a i l s on the (n,nD)

experiments presently i n progress a t Casaccia and mentioned on p, 79.

Concerning the Saclay work on the measurement- of neutron f l u x from

3 a the ~ ( ~ , n ) ~ e react ion by observation of t he He pa r t i c l e s (p, 12.5)~

Joly s a id t h a t the t r i t i um t a r g e t s had been made by t r i t i a t i n g (at saclay)

some evaporated t h i n t i tanium t a rge t s supplied by BCMN. More d e t a i l s

would be given a t a forthooming eonference on neutron producing t a rge t s

t o be held in Grenoble, Jo ly prumised t o send Story a copy of the t h e s i s

9 re la t ing t o t he Be (n, 2n) measurements reported on p. 18).

Story asked if the resonances in the capture cross-seetion of i r on

below Z keV (see p. 53) observed by F. Mitzel and H, S, Plendl ( ~ a r l s m h e )

were genuine,since, a s far as he knew, no resonanoes below 1 keV had

previously been reported, Goldstein and Havens thought t h a t they were

probably due t o Managanese o r Cobalt b p u r i t i e s present i n the sample and

* Number given EANDC(J)2"UU

suggested t h a t Beckurts arrange f o r the sample t o be analysed, Beckurts

agreed t o make the arrangements but said t ha t it was not possible t o repeat

t h e experiment since the apparatus had been dismantled,

Neve said that Spaepen and he were considering whether fu r the r

23 measurements on Na uTOT were required bearing i n mind the discrepancy

between recent measurement$ a t t h e University of Louvain (see E A N D C ( E ) ~ J )

and previous Aldermaston data,

0 No comments.

1 0 ~ ) 3 6 - Progress Report from Sweden

Concerning 81, S t a d e l t s a id that Sweden had recent ly measured the

r a t i o s of (spontaneous) t o 5 uZJ5 a t thermal, 4.0 keV, 7 b1eV and

14 MeV and the r e s u l t s were i n exeellent agreement with previous data,

U c 4 Attention had now been turned t o Pu measurements and also a c r i t i c a l

review of the previous absolute measurement of ~f~~~~ t he l a t t e r being

stimulated by the discrepancy with the reeent data of D. Colvin and

M Sowerby (AERE) . I n answer t o a question from Taschek, S t a r f e l t sa id t h a t the

spher ical proportional counters mentioned i n item 5, p,2 were of Aldermaston

design and were used f o r spectrum measurements ins ide the f a s t reactor,

Goldstein w a s perturbed by the large v a d a t i o n with energy of the

spin-orbit potent ia l (see Table 2 p, 12) and suggested t h a t such a

var ia t ion i s removed i f f i ts a r e made allowing 7 adjustable parameters a t

each energy. He a l so asked i f S t a r f e l t had managed t o obtain an estimate

of a capture cross-section at 7.5 MeV (see item 6 p. l&), S t a r f e l t

rep l ied tha t the cross-section was a few mb f o r emission of high energy

y-rays,

i 0 ~ ) 3 7 - Progress Report from Spain

The W C noted with pleasure t h a t Spain w a s now making a useful

contribution t o the f i e l d of neutron data measurements.

( 0 ~ ) 3 8 - F'roPress Report from Austria

Weinzierl remarked t h a t the technique of measuring burnup of nuclear

f u e l s by high resolution y-spectroscopy had proved t o be successful, the

aocuracy being about l&

I o R ) ~ ~ - Progress Report from N o w

The Chairman asked i f it was feas ib l e f o r Nomay t o undertake a

precision neutron data measurement e.g. the Pu 239 thermal c m s s section. '=nf

S t a r f e l t repl ied tha t he thought it was doubtful because of shortage of

staff .

(OR)@ - Progress Report fmm Switzerland

No comment S,

Smets said t h a t Turkey had responded t o t h e request f o r progress i n

the f i e l d of nuclear data measurements and he supplied a l is t of papers

recently published on the topic (see Appendix 7).

(us )~o , WASH-1053 -Reports t o the AEC Nuclear Cross-Sections Advisory GPOUQ

Goldstein b r i e f ly reviewed the data measuring a c t i v i t i e s in the USA.

He said t h a t A. B. Smith (BNL) was continuing h i s e l a s t i c scat ter ing

programme with measurements on Rg, Au and Tb and A. J, Elwyn (ANL) was

10 studying e l a s t i c mat te r ing by B , B" and Na f o r incident energies

between 70 keV and 500 keV. Sai lor e t a 1 (BNL) were beginning t o use

polarisation measurements t o i n f e r spin assignments of resonances and

235 a t ten t ion would soon be focussed on D Columbia University w a s

concentrating on obtaining values of l'y f o r the l i g h t and r a re e a ~ t h

26 elements, The measurements on 0 (n,n) by D. L is te r and A. Sayres a re

now complete. A study of p-wave e f f ec t s on separated KO isotopes i s i n

progress a t Duke University and E. Haddad ( ~ e n e r a l ~ tomfcs ) has s tar ted

a measurement of the Nb a(ny) up t o several hundred eV, H, Barsohall

(wiseonsin) had made m t h e r uTOT measurements but had not observed the

s t ructure reported by the W o r d group. Lockheed were measuring the

~ e ~ ' ( n , ~ ) and ~ ~ ~ ( n , y) cross-sections and capture cross-section measure-

ments were continuing a t ORNL, The National Bureau of Standards had

entered the data f i e l d and the e f for t was expected t o grow especially when

the l h a c f a c i l i t y w a s operational. Taschek sa id that W, S te in (LASL)

23: 235 u23* and Np . had remeasured the r e l a t ive f i ss ion cross-seotions3f U , The r e su l t s fo r N~~~ were very different from previous data.

( ~ ~ ) 5 4 - Nuclear Physics Division Progress Report. AWE

Bretscher said t h a t the (n,no) programme with IBIS was continuing

with measurements on u~~~ and Fu239. C, A, Uttkey had made fur ther

239 measurements on Fu uTOT and had shown t h a t the strength functions

obtained from individual resonances were l e s s than those calculated by

averaging, E. Lynn had been able t o explain t h i s e f fec t m d the topic

w i l l be discussed at the forthcoming Antwerp Conference, Havens s t i l l .

had reservations about the averaging process although he conceded tha t

was eas ie r t o deal with than u~~~ since the resonances a re mch

stronger,

-urea the Neve pointed out thatMaekl3.n and Gibbons (0%) had mea,

10 B (n,a) branching r a t i o a s a function of energy and hadl obtained values

i n reasonable agreement with M. Sowerby, Quoting from an abs t rac t subr.ii.ttcd

t o the Antwerp Conference he said t h a t the MackLin and Gibbons values f o r

~ ' ~ ( n , a ~ ) ~ ' ~ ( n , a ) were 0.084 - + 0.005, 0.077 2 0.004, 0.072 2 0.003 and

0.067 0.002 a t 160 keV, 110 keV, 30 keV and thermal respectively,

Batchelor gave some d e t a i l s of recent prngress a t A m . He said tha t

neutron scat ter ing measmments had been made on the L i isotopes a t 10 MeV

using the Tandem T.O.F. speotrometer an6 t h a t work on iVi(n,ril) and ~ r . ( n , n ' )

sTas i n progress using the 6 MV machine. P. H. White was con-i;initj.ng

f i s s i o n cross-section r a t i o measurements a t incident energies above

500 keV and D. Mather w a s using the giant s c i n t i l l a t o r t o meanuxe (v,?n)

cross sections of ~ e j , T, t he L i isotopes and ~u~~~ a t 14 MeV. The

P-heating experiment i s now f inished and curves w i l l be available f o r F

the P power emitted from 1 sec a f t e r f i s s ion t o beyond 2 x I d sec. The

t o t a l P energy released per f i s s i o n i n u2j5 i s estimated t o be 7.4 2 0.2 MeY.

The neutron capture cross-sections f o r and d@ isomers have been

measured by mass speotrometry. The thermal cross-sections a r e 83.3 ?; 7.8 b

from t o the 5.4 d isomers 73.4 2 7.4 b t o the 41.5 d Pm 148

isomer and 21,000 2 2,500 from the 41.5 d Pm1@ isomer t o The

resonance in t eg ra l cross-sections a r e 610 2 100 b from Pm447 t o the

5.4 d isomer an& 590 - + 100 b t o the 41.5 d Pm448 isomer. A measure-

1 47 ment was a lso made of the cross-sections f o r Sm ; these a r e 50.9 + 2.5 b

f o r thermal neutrons and 620 ;L 50 b f o r epithermal neutrons.

2(c) Consideration of t he various research papers

In t h i s session there was very l i t t l e discussion on the papers

submitted since many were f o r information only and some (uK)~o, 9 , 52,

53, and 55 and ( 0 ~ ) 3 4 were relevant t o item 2(d).

Referring t o ( G B N ) ~ ~ and 26, Batchelor asked Hanna i f he thought 235

t h a t f'urther measurements of thermal a f o r u2j3 and U were required,

Hanna said t h a t although present datawereprobably adequate, it was

desirable t o have more from measurementsmade i n a purer spectrum. Chalk

River planned t o make such measurements i n a spectrum with a Westcott

r value of 10-'; the temperature would be known and data would be obtained

a t two temperatures.

2(d) Report of the Sub-committee on Standards

Spaepen explained t h a t the EANDC had always been concerned with

standards and the problem seemed t o be increasing i n importance.

Following a suggestion by Havens the Chairman had decided t o s e t up a

standing sub-committee on standards and had invited the following EA.NDC

members t o serve: Spaepen (chairman), Havens, Hanna, Taschek and Batchelor . Two outside experts D r . H. W. Koch (NBS, washington) and D r . E. R. Rae

(AERE, ~ a r w e l l ) had a l so accepted the invi ta t ion t o s e w e on the sub-

committee. Spaepen said t h a t it was expected tha t the European and

N. American groups would meet separately on an ad hoc basis and would meet

together just p r io r t o a full EBNDC meeting. The European group had met

at HarweU on March 4 th and the full sub-committee a t NBS Washington on

May 13th and 14th.

Spaepen asked f o r EANDC's approval of t h e frame of re ference

and t h i s was given. The W C a l so agreed t h a t i t s working group on f lux

measurements no longer existed. He then elaborated on t h e proceedings of

the Washington meeting and s t ressed the following points.

Regarding neutron f l u x standards i n t h e 1 keV t o 100 keV region the

sub-committee requested t h a t EANDC take note of the following recommendations.

10 (i) To press f o r reports on a l l outstanding experiments on B (n,cr)

6 and Li (n,a) t o be circulated a s soon a s possible.

10 (ii) To i n i t i a t e new measurements on ~ " ( n , ~ ) and B (n,t) cross-

sections. An act ion was put on Goldstein (as Chairman of NCSILG) t o

see i f ORNL could be persuaded t o take on t h i s work.

239 ( i i i ) To i n t i a t e new measurements on the f i s s ion cross-sections of I 'u .

and Batchelor s t ressed the urgency of these measurements i n

view of the large discrepancies between recent ANRE data (see

( U K ) ~ O and 53) and the BNL 325 curves. Some recent preliminary

linac data obtained by G. D. Jamesj (AERE) supported the low AWRE

values but the accuracy of the linac data above 1 keV was low and

some new precise data were required. Beckurts said that Karlsruhe

had plans t o measure the Fu 239 t o u~~~ fission cross-section rat io

but Batchelor thought that a new absolute measurement was required.

(iv) To obtain the advice of reactor pwsic i s t s on the accuracy

required on U '=nf 235 and ,239 OaP i n the 100 keV region. The UX

i s presently requesting a @ accuracy and if th is cannot be relaxed

then a very major research effort w i l l be required t o satisfy the

requests. When the discrepancies are resolved, it i s considered

that the overall accuracy from present measurements w i l l be about

3 Story was asked t o discuss th i s point with the requestors

and t o seek an explanation of ww the UIZ. request fo r Fu239 was

Priority I and that for u~~~ is Priority 111,

Some discussion followed on how a f lux could be measured using either

10 6 the standard B (n,ac) o r Li (n,a) cross sections. Starfel t argued that

BCMN should obtain and standardise a lithium loaded glass scinti l lator

but it was pointed out that it might not be necessary t o go t o this

6 length. If the Li (n,a) cross section i s known from thermal t o the McV

region, then a f a s t f lux could be measured with a lithium loaded scinti l-

la tor which has been calibrated i n a known thermal flux. This method would

6 bypass the di f f icul t problem of measuring the L i content of the glass

and the conversion efficienoy of the scinti l lator .

On the question of compilation and evaluation of data related to

nuclear energy standards the -C agreed that the sub-committee should

concentrate on the reactions mentioned i n Appendix 10 and suggested

the following amendments and additions.

23i5 change energy range t o t h e m 1 and 10 keV t o 5 MeV. ( i ) f o r U onf

( i i ) f o r PU 239 mnf change energy range t o thermal and ?O keV t o 3 MeV.

(iii) add u~~~ unf from threshold t o 1 5 &V (suggested because a

detector based on t h i s cross-section would not he sensi t ive t o

thermal neutrons).

A t Beckurts request the sub-committee was a l so asked t o consider

adding In o(aag) in t h e ? keV t o 400 keV pegion t o t h e list.

Crandall pointed out t h a t the EACRP i s a l so interested in standafl

cross-sections and could probably suggest cross-sections other than those

mentioned in Appendi X 1 0 which ought t o be c onsidered. He w a s

inv i ted t o r a i s e the matter a t the next EAGRP meeting and ask if the EACRP

could collaborate jo ln t ly with EANDC in nddng a s t a n d a d s l is t ,

Spaepen sought the support of EANDC i n the proposed a c t i v i t y of

evaluation of standaxd cross-sections a t B M , T h i s was agreed although

Taschek had some reservations about s t a r t i ng a new evaluation centre.

He considered et was f ea s ib l e f o r existing evaluation groups t o take on

t h i s extra work,but Batchelor and Goldstein countered and said t h a t exis t ing

groups were f i l l y occupied and s tandard cross-sect ions were not p r imar i ly

t h e i r business .

Regarding p l u t o ~ u m isotopic standards, Spaepen asked Crandall t o

ge t t h e EACRP advice on the desirable compositions of such standards from

the point of view of burnup studies,

2(e) Round Table Conference on Precision Chemical Analysis

Spaepen said t h a t this was the f i r s t of two round tab le conferences

which BCm planned i n r e l a t ion t o the problem of assay of materials of

i n t e re s t t o nuclear energy. It was held i n Brussels, Jan 18-22, 1965,

Discussion had been lfmited t o B, Th, U andpuand the proceedings are

published i n EANDC-&2S, Spaepen said that one of the benefits of the

coflerence was t h a t it had made chemists more aware of the needs of

physicists and physicis ts more aware of the d i f f i c u l t i e s invokved i n the

chemical analysis of t h e mate~i.als they used.

3. DATA INDEXING. COMPILING m EVBLUATING

3( a) lAEA a c t i v i t x

Westcott reported t h a t t h e LAEA Data Unit had now completed the

2200 d s e c evaluation of t h e f h s i l e isotopes and t h a t the f i n a l report

would be published i n Atomic Energy Review, The f i n a l tab le of

recommended values, suppliea bywestcot t , i s given i n Appendix 8. T h i s

data provoked some discussion on the present s ta tus of measurements

since the was aware of the discrepancy between the Colvin and

Sowerby data f o r G spontaneous and other data. The f igures given

by Hanna are: - ( i ) C o l a and Sowerby 3.713 + 0,015

(ii) Average of LBSL and Swedish values from tank experiments 30793 2 0.023

(iii) Value from 17 and a of u~~~ and and r a t i o s 3,802 5 0.019

( iv) Average of ( i i ) and ( i i i ) 3.797 2 0.015

(v) Difference between ( iv) and ( i ) 0.084 + 0.021

Hanna belfeved this t o be a r e a l discrepancy but S t a r f e l t considered

that the overal l e m r s may not have been properly assessed. Goldstein

sa id t h a t the EANDC should regard t h i s a s a serfous discrepancy and should

take s teps t o improve the s i tuat ion. Batchelor suggested t h a t it might

be useful t o arrange a meeting of g measurers a t the time of the Antwerp

Conference and was agreed, An action was put on S ta r f e l t t o make

the arrangements and it was suggested tha t he inv i t e D.W. Colvin, M.G.

Sowerby, B.C. Diven and an AWRE r ep resen ta t ive t o a t tend .

3(b) Remarks on Evaluation and Mul t imup Cross Sections

Dr. R. B. Lazams (LASL) addPessed the EANDC on t h h topic and a

copy of h i s notes i s included i n Appendix 9 ) A t the conclusion of the

session the Chairman thanked D r 0 h e a r u s f o r h i s most in te res t ing

contribution,

4(a) EANDC-Sponsored Conference on t h e Study of Nuclear Structure with Neutrons

Ngve reported on the s t a tus of t h e arrangements f o r the EANDC sponsored

conference t o be held in Antweq, July 1965. He said that the t o t a l

number of contributions was 472 which, although large, was w a g e a b l e since

a mpporteur system i s t o be used, So far there had been 338 applications

t o attend, 300 being fron EQM)C countries and 2 f r o m the USSR, The largest

contingent (46) was from t h e FederaP Republic of etmany, The North Holland

Company had agreed t o publish the invi ted ta lks , the rapporteurs' reports,

t h e discussions and the abstracts of t h e or ig ina l contributions. The

aotual contributions would be published i n a CEN, Mol, report , and the

abstracts would be circulated as an EBNDe 'Uw document in June,

On behalf of the EANDC, Bretscher thanked Neve f o r his large contri-

bution t o the organisation of the eonferenee and expressed the hope tha t the

venture would be successful.,

4(b) Round Table Conferenoe on Mass Spectrometry and Counting Techniques

Spaepen explained t h a t t h i s conferenoe was the follow up of t h e

conference on precision ehemical analysis held a t BCMN in January, It

was t o be held a t BCMN at the end of November 6965 and the proposed

programme had been circulated t o EBMEe members in April. An act ion was

put on members t o submit games of par t ic ipants t o Spaepe:: by mid June.

4(c) Hamell Seminar on Makk of Isotopic Targets

Batchelor sa id t h a t arrangements were being made to hold a seminar

on making isotopic ta rge ts a t Harwell October 20-2%, 1965. It w a s intended

t o concentrate on s tab le isotopes a d there would be sessions devoted t o

t h e t e c h n i ~ e of measuring t a rge t thickness. It was a lso expected t o

include a session on d i r ec t deposition of ta rge ts in mass-sepawtors. 4

EANDC gave i t s support t o this semfnw and Batchelor agreed t o c i rcu la te

the programme t o members as soon as possibI.e, At Spaepenos ~ e q u e s t he

a l so agreed t o discuss with t h e organisers the f e a s i b i l i t y of publfshfng

tb+e f u l l dhe,ussion of the seminar.

4(d) High Intensi ty Neutron Sowoes

This topic was opened by Kolstad who said t h a t the USAEC had held

a symposium on high in t ens i ty neutron sources in Washington fn Febmary 1965.

The programme incPuded dfscussions on the needs f o r high fn tens i ty sources

and the technique of" mak%nag such sources, A t the conclusion of the

symposium, a special panel had met aPid i ts preliminary report ana

recommendations have been issued a s EANDG(US)~&U, Havens had summarised

the proceedings and he voPmteered t o c i rcu la te his sunmaqy t o

members. In view of the growing h t e r e s t i n the f i e ld , Kolstad thought

that, EBNDC be in te res tea organising another coderenae.

Considerable discussion followed duPing which it became c lear that

thepe were m a y o o n f l i ~ t b g opinions about such a conference. Some f e l t

t h a t it should be r e s t r i c t e d t o nuclew physics b t e r e s t s , some t h a t it

should encompass a l l t h e d i s c i p l b e s associated with the devices. An

agreement was eventually reashed on the following Kolstad proposal "That

* I t i s now lcnown t h a t there w i l l not be a session on d i rec t deposition of ta rge ts i n mass-separato~s.

t he recommends t h a t a s m a l l symposium on very high ixkensity neutron

sowees f o r nualear energy research be held dupSaag the l a t t e r half of

1966 aaad urges t he participation of t h e EACRP in developing t b e appropdate

arrangements and programme".

4(e] Neutron Cross-Section Te&noloa

Havens announced t h a t it was intended t o hold a conference on "Neutron

Cross-Section Technology i n Washington 22-2& March 1966, sponsored by t h e

USBFCqthe National Burea of" Standards, t he American Physical Soelety and

t h e American NmBear Soeletty, The arrangements agd programme would be

formulated 5x1 June W.& Havens promised t o c i rcu la te the information t o

-6 members.

5. REQUEST LISTS

5 (a ) ~u~~~ F i s s i o n Cross Sec t ion a t 2200 m/sec

Hanna s a i d t h a t t h e r e were r eques t s f o r t h i s parameter t o YA6 and 1%

accuracy and although an in spec t ion of t he Westcott recommended values

( see Appendix 8) sugges ts t h a t t he r eques t s might be f u l f i l l e d , t he s i t u a -

t i o n is f a r from s a t i s f a c t o r y . A new measurement had r e c e n t l y been made

(Fraysse and Prosdocimi, Paper SM 60/17 of t he S d s b ~ g F i s s i o n Symposium),

bu t Hanna had some r e se rva t ions about t he r e l i a b i l i t y of t h e r e s u l t and he

thought t h a t i t w a s d e s i r a b l e t p programme a new measurement i n a monokin-

e t i c spectrum. Spaepen agreed with Hanna's remarks and s a i d t h a t Ngve and

he were planning such a measurement u s ing a d i f f e r e n t approach from t h e

previous Mol experiment. Batchelor s a i d t h a t Aldermaston planned t o

measure t he r a t i o ~u~~~ g n f / ~ ~ ~ ~ @ nf u s ing a c r y s t a l spectrometer but

t h e expected accuracy on t h e r a t i o is 2%.

5 ( b ) I n e l a s t i c S c a t t e r i n g

I n t h i s i tem the Chairman c a l l e d f o r comments on the s t a t u s of measure-

ment on P r i o r i t y I ( n , n t ) items. IBIS type machines were now producing

a l o t of high r e s o l u t i o n da ta , p a r t i c u l a r l y i n t h e reg ion up t o 2 MeV

i n c i d e n t energy and higher energy s i n g l e ended and Tandem machines were

be ing equipped with bunchers s o t h a t high r e s o l u t i o n work a t high energ ies

could be expected i n t he fu tu re .

The fol lowing Table summarises t he d i scuss ion on the ( n , n t ) reques t s ,

t he i t em numbers being taken from EANDC 43"U".

Item No, Comments

Na umO t o 10 MeV Data available up t o 4 MeV Nuclear Physics z, 610 (1962)

t o make measurements i n region of" 7 MeV.

142 A 1 am, t o 10 MeV Data a v a i l a b l q see EANDC4Jt'U" A m t o make measurements i n region of 7 YeV

366 Z r ann, 1 t o l& MeV See EANDC 43"Uw f o r available data I 387 93 IRb am, t o 8 &V Activation measurement. Hanna t o

b v e s t i g a t e whether Chalk River can measme

394 MO a,# t o 3 MeV JoToly and S t a r f e l t offered t o consider making measurements

41 8 %'OS amo t o 10 M ~ V In progress a t Chalk River I 528 ~h~~~ mmO t o 10 MeV Batchelor thought t ha t this request

i s now f l i i f i l l ed from data obtained a t ANL and AlARE

656 and f f m ~ t o 10 MeV AWE have made measurements up t o 657 i -5 &V

ABlRE plan measurements t -5 MeV t o 7 MeV

7 MeV from data obtained a% AWE and A m , 3% accuracy not achieved and S t o q t o cla1"*,

I n answer t o a quest ion from Bretscher , Goldstein s a i d t h a t from t h e

appl ied po in t of view, i t was not necessary t o reso lve l e v e l s by ( n , n l )

above 700 keV i n c i d e n t energy f o r the f i s s i o n a b l e i so topes ; t he s t a t i s t i c a l

approach was good enough above 700 keV, Taschek pointed out however t h a t

t h e r e might be a good physics reason f o r r e so lv ing higher l e v e l s and

experiments should be encouraged t o follow such i n t e r e s t s ,

6. PRODUCTION OF BERRYLIUM SINGLE CRYSTALS

N6ve said t h a t the document I W D C ( E ) ~ ~ S summarises the present

s t a tu s of the beryllium s ing le c rys ta l problem, A c rys t a l has been

made by the Metallurgy Division of CEA, Saclay and has given promising

r e su l t s on t e s t s with neutrons a t Mol although there i s evidence t o suggest

t ha t it i s not a pure single crysta l , However it i s planned t o t r y t o

improve the c rys ta l and t o manufacture a second c rys ta l under more

controlled conditions. If these a r e successful then Neve w i l l discuss

with CEA the question of producing c rys ta l s t o s a t i s f y the known demands,

The EANDC enoowaged t h i s investigation t o continue.

Smets said t h a t t h e OR group sought the help of EANDC i n establishing

a catalogue of producers of gooa single c rys t a l s o r ownersof unused

crysta ls . Denmark was interested i n sodLum and potassium and Austria

in sodium crystals . Since the c rys ta l s were required f o r sol id s t a t e

studies, the W C f e l t t ha t it could not help i n t h i s matter.

NOTE ON TOPICAL DISCUSSION

The morning of Tuesday May 18th was devoted t o a discussion on Neutron

Capture Reactions. The session was organised by D r . B.C. Diven of LASL and

D r . E. Haddad, General Atomics, D r . L, W. Weston (oRNL) and D r . R. Blose

(OF@&) attended a s experts.

P P P E I U J ~ a

L E T OF GEG3IU.L DOCUMENTS

For 8th Meeting of EANDC

No, - Classification Ti t le Author

EWDC-36 A Complete Minutes of the Seventh R. Batchelor Meeting of the Committee W, Michaeli S

EANDC-40 A Cumulative L i s t of EANDC Documents September 4 959 - July 1964

EANDC-41 A List of Members

S Round Table on High Precision Chemical BnKi.ysis of Substances of interest t o Nuclear Energy

-c-43 U Compilation of EBM)C Requests

APPENDIX 2

LIST OF CANADIAN DOCIBBNTS

For 8th Meeting of EANDC

H0 L Classification Ti t le

E A N D C ( C ~ ) 23 L Pmgress Report

m G. C, Hanna

EANDc(c~~) 24 L Request List G. C, Hanna

~ F l C ( ~ a n ) 2 5 S A Detednat ion of the Ratio of A. Okazaki &CL-l 965 Capture to Fission Gross Sections M, Lounsbwy

of ~2.35 R, W, D u r h a m I, H, Crocker

~ ~ ( 6 a n ) 26 S & Deterna t ion of the Ratio of A, Olcaaakf BECL-21 48 Capture t o Fission Cmss Section M, Lounsbury '

of R. W, Durham

EILNDC(CW) 27 S Fission Data and Nuolear Technology G. C, Hanna '

APPENDIX 1

LIST OF EURATOLT DOCUh1ENTS

FOP 8 t h Meeting of WC:

No.

m C ( E ) 5 2

W ~ c ( E ) 5 5 KFK 265

Classi f icat ion T i t l e Author

S Cross Sections f o r the Reactions H, Liskien Cu63 n,a h6O8 ~ i 6 0 ( n )c060 A. Paulsen ~ i 4 6 b , ~ ] s c k 6 , and Na@(n,2njNa22

S Automatic Acquisition and Reduction K, H, Beokurts of Nuclear Data - Karlsruhe Meeting ';/. Glaser

G. Kruger

S Mesure de la section eff icace de Leroy capture du Sodium pour des neutrons dQEnergie comprise entre 10 keV e t 100 keV,

L Eine Messung des isomeren A ~ f s ~ a l t v e r h ~ l t n i s s e s be i Aktivierung i n den ers ten 3 Indiua-Resonanzen

E. Albold P. v.

Blankenhagen

S Excitation Functions of the Reactions iJi.Paulsen ~ i 5 7 , ~u65(n ,2n)~u64 and H, Liskien 21163 i n the Energy Range

between 12,5 and 19,6 MeV

U Progress Report on Nuclear Data Research i n t he Euratom Community f o r the period 1,7,63 t o 31,12.64

U Compilation of Requests f o r Neutron Data from Euratom Countries

S Test Equipment f o r Accurate Deter- H. Meyer mination of Time Relations and i t s H, Verelst Use f o r the Measurement of the T i m i n g Accuracy and the Calibration of Fast Photomult ipl ie~s

S The Correction f o r Foi l Absorption W. van der Eijk i n 4 47s Counting

S Cmss Sections f o r the Reactions A, Paulsen H, Liskien

i n the 12.6 t o 19.6 MeV EnergyRegion

S Two Compact, High-Intensity Neutron K , Eyrioh Sources A. Schmidt

S Progress Report i n the Field of G , DeCcnninck Neutron Data DeVroey

S Test of a Be Single Crystal F, Poo~tmans E. Legrand

APPENDIX 4

LIST OF DOCUMENTS. FROM OTHXR OECD COUNTRIES

For 8 th E&NDC Meeting

No. - Classif'ication T i t l e Authop

EANDC(OR) 34 L A Relative Measurement of the S. Schwarz FOA 4 Report ~ i 6 ( n , a ) ~ 3 Reaction Cross Section L. G. Stromberg A 4393-41 1 i n the Range 1 < En 600 keV A, Bergstrom

wDC(OR)35 L Progress Report t o EANDC from H, B j e m Danish AEC Research Establishment ~ b l l e r

E A N D c ( o R ) ~ ~ L Progress Report t o EANDC from No S t a r f e l t Sweden

L Spanish Progress Report t o t he EANDC

EANDc(oR)~~ L Progress Report t o EANDC from Austria

EANN(oR)39 L Progress Report on Nuclear Data Measurements i n Noprvay

EANDc(oR)~o L Progress Report t o EANDC from Swit serlank

No. - ~ m c ( m r ) 4 6

APPENDIX 5

LIST OF UNITED KINGDOM DOCUMENTS

For 8 t h Meeting of EANDC

Classification T i t l e

S A Neutron Scattering Study of Fe 56

S The Absolute Fission Cross Section of ~ 2 3 5 f o r 2200 m/sec Neutrons

S Neutron Interactions with u~~~ m d ~ h 2 3 2 i n the Energy Region 1.6 MeV t o 7 MeV

22.

P. Weinzierl

R. W. Meier

Author

W, B, Gilboy J, H, Towle

E, E, Maslin J. A. Moore J, M. A, Reichelt J. B. Crowden

R. Batchelor W, B, Gilboy J, H, Towle

APPENDIX 2 (continued)

LIST OF UNITED KINGDOM DOCUMEh'TS

For 8 t h Meeting of W C

No. - Classif icat ion Title But hor

-C(UK)~Y S Measure of Prompt f o r the Neutron- D. S, Mather Induced Fission of ~ h 2 3 2 , ~ 2 3 3 , P. Fieldhouse ~ 2 3 4 , U238 and F11239 A. Moat

-c(~)w S The Fission Cro s Sections of u233 J, L. Perkin v234 ~ 2 3 5 , ~ 2 3 8 , ~ ~ 2 3 7 , ~ ~ 2 3 9 , P. H. White F u 2 d and ~ ~ 2 4 1 f o r 24 keV neutrons P. Fieldhouse

E. J, Axton P. Cross J. C. Robertson

Correction t o EQNDc(UK)42 L

Measurements of t he235~ Neutron P, H, White Fission Cross Section i n the Energy Range 0.04 MeV t o '14 MeV

Boron P i l e Measurements February 196.5

D, W. Colvin M. G. Sowerby

Measurements of Fission Cross P. H, White Sections f o r Neutrons of Energies 5. G, Hodgldnson i n t he Range 40-500 keV G. J. Wall

Nuclear Physics Division Progress D, L. Allan Report f o r Period I s t January 1964 Editor t o 30th June 1964,

The j%(n,a) Branching Ratio M, G. Sowerby

The Neutpon Confliction of Thorium M, Asghar and the Analysis of t he Resonances C, M. Chaffey up t o l keV. M. C. Moxon

M, J. Pattenden E. R, Rae C. A, TJttley

Neutron Scattering Studies of K 39 J. H. Towle

Stock of Plutonium and Thorium M, L, Smith Isotopes held by Electromagnetic Group, Chemistry Division, m, Hamell .

Eta and Neutron Cross Sections of ~ 2 3 5 from 0.04 eV t o 200 eV.

23

M. G. Sowerby

APPENIUL 6

LIST OF UNITED STATES DOCUMENTS

For 8 th EANDC Meeting

No. - Classif icat ion T i t l e Author

EANDc(us) 68 B ORNL Plutonium Inventory, 22nd January, 1965

EANDc(us)~O U Beports t o AEC Nuclear Cross A. B. Smith WASH 1053 Sections Advisory Group (ORNL) ,

October 43-14, 1964

EANDc(us)~I U A n u s i s of (n,2n) Cross Sections S. Pear ls te in f o r Nuclei of Mass A > 30.

E B N D C ( U S ) ~ ~ U Reports t o the AEC Nuclear Cross KASi 10% Sections Advisory Group ( ' ~ash in~ ton ,

D e c . ) , March 8-9, 1965

E A N D C ( U S ) ~ ~ U Compilation of Requests f o r Nuclear WASH 1057 Cross Section Measurements

W D C ( U S ) ~ ~ U Report and Recommendations of Special WASH 1058 Panel on Pulsed High In tens i ty

Pission Neutron Sources, Pebmary 19, 1965

EANDc(us)~~ U Least S q u a ~ e Analysis of t h e 2200 R, Sher m/sec Parameters of u233, u235 J, Felberbaum and h 2 3 9

.EANDC(us)76 L Stable Isotope Cross Section Research Pool Inventory, April 1965 (USAEC)

E A N D C ( U S ) ~ ~ A U,S, Nuclear Physics Research Aocelerators (1 MeV - 1 B ~ v ) , Apri l 1 965 ( draft)

APPENDIX 7

LIST OF REPORTS AND PUBLICATIONS FROM TURKEY

Nuclear Data

&l reports a r e obtainable, from:

The Secretary Sc ien t i f ic Publications Cekmece Nuclear Research and Training Center P.O. Box 1, Airport Istanbul, Turkey

1. T. Erben and B. Guven: Isotopic and Isotonic Yields i n Nuclear Fission, CNAEM rep. 2, 1962, published i n The Phys, Rev. a, 1762-1764 (1 963).

2. Z. Guner: Investigations of Experimental Equipment f o r Ine l a s t i c Neutron Scattering Using a Low Flux Reactor, CNAEM rep. 4, 1962

3. T. Erben: Nuclear Charge and Mass Distributions i n Low-Energy Fission (Chemistry Research and Chemical Techniques based on Researoh Reactors, IAEA, Vienna 1963, pp. 61 -72

4. T. Erben: Studies on Nuclear Charge and Mass Distributions in Low Energy Fission, presented at the Athens Study Group Meeting, 9-1 3 September, 1 963

5. F. Domanic: Neutron Crystal Spectrometer Project of the CNAEM, presented a t t h e Athens Study Group Meeting, 9-1 3 September, 1963

6. T. Erben and B, Guven: Systematics of Fission Asymmetry with Respect t o Nuclear Charge and Neutron Contents, CNAEM rep. 12, 1963, published i n Phys. Rev. l&, No. 5B, 972-976 (1964) W

7. 0. JUL$Z, F. Bayvas, C. Cansey, F. Domanic: Crystal Spectrometer Measurement of Celcmeoe TR-l Thermal Neutron Spectrum, CNAEM rep. 19 (1 964)

RECOWLENDED VALUES PO3 F I S S I L E ISOTO?ES

( a l l c ros s s e c t i o n s i n barns)

APPENDIX q

REPORT ON THE USE O F L I B R A R I E S O F EVALUATED NEUTRON INTERACTION DATA

1. The primary i n t e r e s t i s i n fast systems.

2, The m&, problem i s t o calmillate, f o r algv nucLt.de o r element, the:

5-parameter neutron p~oduct ion cross sections 8

Gr,m9,g +g* = j m [ / dilPrn(d. @,PI

g -% l

P

T 1, a& n;, (E + E O , ~ P~ ( ~ ~ 1 ~ g P

where P i s a reaoti.un ( smh a.5 n , 2 ~ ~ ) ~ B ( E , J ~ ) is an estimate of the

neutron distr3.butfon f o r the prrtblelo a t hand, P m and Pn are Legendz'e

polynomials, and g and g q labe l energy groups,

3 4 10 t o 10 of these cmss sections are needed f o r eac;h nuclide

fo r each (substantially different) application, They can be calcu-

lated in a few minutes on a modest computer, assuming good programming.

3. Libraries of -r E 8 , p ) presently in, hand contafn a few times id 6 numbers and are expected t o reach 10 nmbe~s . They can be contained

(if suitably packed) on one ree l of magnetic tape, w%th a random

access tfme of the opdep of two minutes o r less, o r they can be

contained on $10,000 t o 8;50,00 wor&h of magnetic disk, with a random

access time of the order of 0.2 seconds or less.

8 l+. Rewirements fo r thermal reactors may go t o $0 numbers of more, but

it appears evident that appropriate technological advances in data

storage w i l l be foAhcoming (cog, optical memories).

5. Work i s in progress f o r the automatic generation of commensurate

plots of experimental and maluated data, as a tool fo r the evaluator,

6* Data problems botheffng me a t prevent 3nc;lude:

(a) Updating l ibrar ies by ~ o m e t i o n , ra6'her than =lacement, to

avoid introduction of e m r s . (1t was correctly pointed out

by Herb h l d s t e i n that almost any updat.ing procedure i s all

Pfght, i f it avoids dimet, interactfon between humans and those

data wMch are not t o be replaced,)

(b) Data and a f w m t are ueeded f o r @(E -9 E Q , P ) fo r other than

two-bow %ritcractions; Ken Parker of AWRF i s believed to have

chosen swh a format.

( G ) Data and a f o m t are nes&ed fo r 7-my production by neutron

collision.

APPENDIX 10

TABLE OF FIRST CATEGORY ITEMS FROM THE GEEL ACTIVITY REPORT

Nuclide Cross Sec t ion E n e r ~ y I n t e r v a l

H (n ,n) up t o 15 MeV

~e~ (%P) up t o 4.5 MeV

C t o t a l up t o 2 MeV

L i 6 (n ,a ) up t o 2.5 MeV

B ~ O (n , a ) up t o 1 MeV

Au (n, V) thermal

Pb t o t a l up t o 10 keV

$35 ( n , f ) thermal and 1 0 keV-15 MeV

Pu 239 ( n , f ) thermal and 10 keV-15 MeV

c f 252 - v spontaneous f i s s i o n