Coppola, M.

Knitter, H.-H.

Archive of European Integration

; í™EPii EUR 345; .;«!!: iikiwtwiiu âm$\ ttthü EUROPEAN ATOMIC ENERGY COMMUNITY - EURATOM ■ ·:<!»; *¡l ItiJrV1*'^ H>¡!-. m Iwiffl !>'»!! ppn .W< ,ιΛί STIC SCATTERING OF NEUTRON! FROM 6Li m $Á* MM 5 '■sffi'SW ?»»#$ mum H.-H. KNITTER and M. COPPOLA mm ï»*fW!l!d ïiwn ìtf* £ffl ar; tø»¥* tttaf artCI" :f Κ iW mm M m m ii«n » M iül ick 1967 HtTw I :ir*H!i: i ¡M ^-u.i'lifí ra«:¡ifn »»Ι HP M ; ■ ' % * <o ί^υ-.'ΓίΐΊ,ιϊΐ M im m Joint Nuclear Research Center Geel Establishment - Belgium ïiiHïLiS'ttPr entrai Bureau for Nuclear Measurements - CBNM Mm ■ ; : . ' , , I ¡'M iSISiìlLlili This document was prepared under the sponsorship of Commission of the European Atomic Energy Community (EURATOM). Neither the EURATOM Commission, its contractors nor any person acting on their behalf : ΐί£?1β^^ίΓ#Λι' 'V ■ troais Make any warranty or representation, ~ respect to the accuracy, completeness, or usefulness of the information contained in this document, or tha t the use of any information, apparatus, method, or process disclosed in this •M resulting from the use of any information, apparatus, method or process disclosed in this document. » t i » at the addresses listed on cover page 4 a t the price of F F 2.50 FB 25, DM2.- Lit. 310 Fl. 1.80 Λ When ordering, please quote the EUR number and which are indicated on the cover of each report. was Printed by L. Vanmelle Brussels, April 1967 ΒΪΑΒΓ Droduced on the basis of the best available ■» -inwoi'tíHaíi[fornir m ni » EUR 3454.e E L A S T I C S C A T T E R I N G O F N E U T R O N S FROM 6 L l by H.-H. KNITTER and M. COPPOLA European Atomic Energy Community — EURATOM Joint Nuclear Research Center — Geel Establ ishment (Belgium Central Bureau for Nuclear Measurements — CBNM Brussels, April 1967 — 14 Pages — 4 Figures — FB 25 Angular distributions of neutrons elastically scattered from Li were measured in the energy region between 1.0 and 2.3 MeV using a fas t neutron time-of-flight spectrometer. F lux at tenuat ion and shape corrections were calculated and the final da ta a re presented in the form of coefficients of Legendre polynomial expansions. EUR 3454.e E L A S T I C S C A T T E R I N G O F N E U T R O N S FROM 6 L I by H.-H. KNITTER and M. COPPOLA European Atomic Energy Community — EURATOM Joint Nuclear Research Center — Geel Establ ishment (Belgium Central Bureau for Nuclear Measurements — CBNM Brussels, April 1967 — 14 Pages — 4 Figures — FB 25 Angular distributions of neutrons elastically scattered from Li were measured in the energy region between 1.0 and 2.3 MeV using a fas t neutron time-of-flight spectrometer. Flux at tenuat ion and shape corrections were calculated and the final da ta a re presented in the form of coefficients of Legendre polynomial expansions. EUR 3454.e E L A S T I C S C A T T E R I N G OF N E U T R O N S FROM 6 L I by H.-H. KNITTER and M. COPPOLA European Atomic Energy Community — EURATOM Joint Nuclear Research Center — Geel Establ ishment (Belgium Central Bureau for Nuclear Measurements — CBNM Brussels, April 1967 — 14 Pages — 4 Figures — FB 25 Angular distributions of neutrons elastically scattered from ^Li were measured in the energy region between 1.0 and 2.3 MeV using a fas t neutron time-of-flight spectrometer. F lux at tenuat ion and shape corrections were calculated and the final da ta are presented m the form of coefficients of Legendre polynomial expansions. 6-EUR 3454.e EUROPEAN ATOMIC ENERGY COMMUNITY - EURATOM ELASTIC SCATTERING OF NEUTRONS FROM 6Li by H.-H. KNITTER and M. COPPOLA 1967 Joint Nuclear Research Center Geel Establishment - Belgium Central Bureau for Nuclear Measurements - CBNM SUMMARY Angular distributions of neutrons elastically scattered from 6Li were measured in the energy region between 1.0 and 2.3 MeV using a fast neutron time-of-flight spectrometer. Flux attenuation and shape corrections were calculated and the final data are presented in the form of coefficients of Legendre polynomial expansions. - 3 -Introduction A systematic study of neutron elastic scattering from Li was realized as a part of a program established to provide data needed for reactor design. Some time-of-flight measurements of neutron scattering from Li were previously accomplished (1-5), hut the data are spread over a large range of ener-gies up to 14 MeV and do not provide a consistent set of ex-perimental results. R.O.Lane et al. (6) have measured neutron differential cross sections of Li between 50 keV and 2.0 MeV using BF.J counters. A complete survey of the neutron cross sections of Li in the energy region 0.001 eV - 15 MeV exis-ting up to July 1964 was made by E.D.Pendiebury (7). More recently R.O.Lane et al. have measured polarization and dif-f( 7-erential cross sections for neutron scattering from Li and Li between 0.2 and 2,0 MeV using the same technique as be-fore. In the energy region of the present measurements also the reaction Uii(n,dn')a with a Q-value of -1.47 MeV is energe-tically possible. However, sinoe these neutrons have much longer flight times than the elastically scattered ones, they contribute to a region far from the elastic peak in the time spectra. In any case also at the highest primary neutron energy no appreciable contribution was observed from the Li(n,dn*)a reaction. Experimental equipment The measurements were performed at the 3 MeV Van de Graaf f accelerator of CBNM using a fast neutron time-of-flight spectrometer. The experimental equipment is the same used for earlier measurements and was already described (9). Neutrons were produced through the T(p,n)JHe reaction in occluded targets 1.0 and 0.6 mg/cm2 thick. The scattering samples were cylindrically shaped and enclosed in very thin aluminium containers. The contribution to the scatte-ring due to the containers was experimentally subtracted using a dummy can. For best detection efficiency two diffe-rent Li samples were used at different energies. Manuscript received on February 10, 1967. _ k -Sample I: Height 2,59 cm; 0 3,67 cm; Weight (12,807 + 0,002)g Sample II: Height 4,98 cm; 0 3,68 cm; Weight (24,666 + 0,005)g. Both samples had an isotopie composition of 95,82$ Li and 4,18# 7Li. Due to the sample-to-detector collimation two different scin­tillators were also used, in conjunction with the above des­cribed samples. Detector I: Stylbene crystal 1 3/4" 0 and 1" height Detector II: NE 102 A plastic scintillator 4" 0 and 1" height. In the case of Detector I the crystal was directly facing the photocathode of a 56 AVP tube, while for Detector II a light-pipe of plexiglass was inserted between scintillator and pho­tocathode. The relative efficiencies of both deteotors were obtained by comparison of the measured yield of neutrons scat­tered from hydrogen at several angles with the known η-p dif­ferential scattering cross sections (10). Proper beam attenu­ation corrections in the hydrogenous sample were introduced. Experimental results Neutron scattering from Li was measured at several angles between 20° and 150°, but for some of the angular distribu­tions the maximum scattering angle was reduced to 145° be­cause of geometry limitations. Angular distributions of elastically scattered neutrons were measured at incident neutron energies of 1.00, 1.10, 1.20, 1.33, 1.40, 1.50, 1.60, 1.70, 1.80, 1.90, 2.00, 2.09, 2.19 and 2.30 MeV, with energy spreads, due to target thickness and finite geometry, of 62, 60, 59, 56, 54, 89, 87, 85, 83, 81, 78, 76, 75 and 74 keV respectively. Por the absolute calibration of the cross sections, at each primary energy the neutron scattering from a polyethylene sample was measured at a certain angle. Absolute values of the differential cross sections were then obtained by COm-parison of the angular distribution results on Li with the H(n,n)H differential cross section values. Corrections for finite geometry, beam attenuation and mul­tiple scattering were calculated with the program MAGGIE (11), - 5 -and the corrected differential cross section data were then fitted with a legendre polynomial expansion of the form 7 $#(*) = > B TP T(cos*). dfl ^ 0 The best fitting curves are presented in figs. 1, 2 and 3 with the corrected experimental points. The values of the Β,- coefficients derived from the least squares fit proce­dure are presented in table I, together with the computed errors, which are only of statistical nature. Overall errors on the absolute differential elastic croise sections are estimated to be around 5$. Integrated elastic scattering cross sections are presented in table II and fig. 4. The agreement with the previous results of R.O.Lane (6) is good. The theoretical interpretation of our scattering data on 6 7 Li and Li is unde future publication. r study and it will be the matter of a The authors wish to thank Dr. J.Spaepen, Director of CBNM, for supporting these measurements. The cooperation of Mr. B.Jay, Mr. C.Rousseau, the accelerator staff and the Sample Preparation Group is gratefully acknowledged. - 6 -References 1) C.Wong et al. Nucí. Phys. ¿¿ (1962) 680 2) R.Batchelor and J.H.Towle Nucí. Phys. £7 (1963) 385 3) P.Merchez et al. Compt. Rend. 260 (1965) 3922 4) J.C.Hopkins LA-DC-7603 (1966) 5) P.Merchez et al. Paris Conf. CN-23/75 (1966) 6) R.O.Lane et al. Ann. Phys. V¿ (1961) 135 7) E.D.Pendlebury AWRE 0-60/64 (1964) 8) R.O.Lane e t a l . Phys. Rev. J J 6 (1964) Β 1710 9) M.Coppola and H.-H.Kni t te r EUR 2798.e (1966) 10) J.L.Gammel in Fas t Neutron Physics Par t I I , J.Wiley e Sons, New York and London (1963) 11) J .B .Parker e t a l . Nucí. I n s t r . JiO (1964) 77 TABLE I Values of the coefficients in the Legendre polynomial expansions in mb/sr (MeV) 1 .00 1 .10 1 .20 1 . 3 3 1 . 4 0 1 .50 1 .60 1 .70 1 .80 1 .90 2 . 0 0 2 . 0 9 2 , 1 9 2 . 3 0 Bo + + + + + + + + + + + + + + 81 8 2 7 8 7 6 77 7 6 7 8 81 7 8 , 84 89 9 5 9 9 . 105, , 4 2 + 1 , 8 4 + 1 . 4 6 + 1 , 3 1 + 0 , 9 9 + 0 »99+p , 1 7 + 0 7 4 + 0 86+0 , 7 0 + 0 , 6 1 + 0 . 3 8 + 0 , 5 6 + 0 20+0 , 3 1 . 4 0 . 5 0 . 2 7 , 5 1 , 7 3 , 9 3 . 3 7 . 6 5 , 4 7 , 5 7 , 7 6 , 7 7 , 6 9 B 1 + 5 9 . 8 9 + 2 + 6 6 . 8 2 + 3 + 5 6 . 0 9 + 3 + 4 7 . 8 3 + 0 + 4 8 . 5 6 + 1 + 3 9 . 7 5 + 2 + 4 7 . 0 9 + 2 + 4 7 . 9 1 + 0 + 4 5 . 7 5 + 1 + 4 8 . 3 9 + 1 + 5 2 . 8 3 + 1 + 6 0 . 5 7 + 2 + 5 7 , 3 6 + 1 + 6 2 . 3 8 + 2 . 3 6 . 1 2 . 1 6 , 7 2 . 2 1 . 1 7 , 64 , 9 8 , 5 5 , 14 27 , 3 3 , 94 , 1 7 B 2 +27 + 19 +20 + 14 +20 + 18 + 12 + 14 + 10 + 1 3 . + 15 , +26 +27 +36 , 1 1 + 3 . 3 0 + 4 . 5 2 + 4 . 9 6 + 0 , 0 7 + 1 . 3 3 + 3 . 4 0 + 4 . 5 9 + 1 . 0 0 + 2 89 + 1 63+1 . 8 9 + 3 . 6 8 + 2 , 7 2 + 3 , 3 9 , 7 1 , 3 1 , 9 7 , 6 6 . 1 1 . 2 8 30 . 1 7 , 6 3 . 7 6 , 3 9 , 7 5 . 0 2 B 3 + 2 . 9 5 + 4 - 0 . 6 6 + 6 , - 8 . 0 2 + 5 , - 1 . 5 4 + 1 + 3 . 1 5 + 2 - 1 1 . 7 0 + 3 . + 1 . 9 4 + 5 - 5 . 3 0 + 1 - 4 . 0 7 + 2 + 1 . 8 8 + 2 , + 8 . 8 0 + 2 +17.80+4, + 1 2 0 1 + 3 +15.76+4 66 . 0 3 , 5 7 , 0 6 , 0 7 , 9 7 . 5 9 . 5 6 . 6 8 10 . 3 1 , 5 3 , 6 5 , 3 2 B 4 +2 - 0 +3 +2 +4 +8 +6 +2 +2 + 1 - 4 +4 +2 +7 , 2 0 + 4 , 3 6 + 5 , 6 7 + 5 , 6 3 + 0 »84+1 , 6 2 + 3 , 9 8 + 4 . 4 7 + 1 . 5 2 + 2 , 3 0 + 1 , 5 7 + 2 , 5 3 + 3 , 2 0 + 1 , 9 2 + 3 . 1 9 . 1 1 , 0 2 . 8 8 , 7 5 . 6 4 , 5 9 , 3 2 , 2 6 , 4 4 , 6 7 , 8 7 , 8 9 . 9 1 B 5 - 1 . 1 9 + 6 . - 3 . 5 6 + 8 - 7 . 8 0 + 7 - 0 . 7 6 + 1 - 1 . 0 5 + 2 - 1 2 . 6 4 + 4 + 5 . 4 7 + 5 - 3 . 3 2 + 2 - 4 . 4 2 + 3 - 1 . 5 2 + 3 + 5 . 9 1 + 2 +12.41+4 + 6 . 9 1 + 3 + 4 . 6 1 + 4 9 2 .31 . 3 1 . 7 7 . 9 2 . 3 2 . 5 8 ,10 , 6 5 . 1 6 . 7 9 , 7 9 . 7 0 . 5 0 B 6 - 0 - 4 + 0 , +0 - 0 +7 +0 - 0 - 0 - 0 +0 +6 +0 +8 0 3 + 0 , 4 7 + 8 , 8 6 + 7 , 0 3 + 0 . 1 2 + 0 . 9 6 + 3 . 2 8 + 6 . 1 0 + 0 . 1 1 + 0 . 1 0 + 0 , 0 2 + 0 , 8 7 + 4 , 7 0 + 1 , 2 4 + 3 . 0 6 . 4 4 , 8 5 . 0 6 . 0 3 . 5 0 . 4 4 . 0 5 . 0 5 . 0 5 . 0 6 . 0 5 . 0 0 . 2 2 B 7 - 0 - 7 - 8 - 0 - 0 - 1 - 0 - 0 +0 +0 - 0 +7 +0 +2 , 0 8 + 0 . 0 6 . 2 9 + 8 . 8 1 . 2 9 + 8 . 7 0 . 0 5 + 0 . 1 0 . 0 3 + 0 . 0 3 . 2 5 + 2 . 9 5 . 4 7 + 6 . 5 8 . 0 2 + 0 . 0 6 . 0 5 + 0 . 0 5 . 0 2 + 0 . 0 6 . 1 3 + 0 . 0 6 . 2 8 + 3 . 9 8 , 8 4 + 1 . 0 6 , 2 8 + 3 . 9 3 I I TABLE II Integrated elastic cross sections (MeV)» 1.00 = = = = = * = = = = = = σ β1 !! 1023 (mb) ¡I * a e l j{ 3 6 (mb) II II 1.10 1040 36 1.20 ======= 985 34 1.33 958 33 1.40 :======: 980 34 1.50 :== = = = = : 967 34 1.60 _ 982 34 1.70 1.80 : = = = = = = | = = = = = = = 1027 36 990 35 1.90 : = = = = = = = 1064 37 2 .00 = = = = = = : 1126 39 2.09 ======== 1198 42 2 .19 = = = = = = = 1250 44 2 .30 = = = = = 1321 46 CO I Ζ ν»-uf fe ι t-Ci TDIT3 I i l —ι Ό 3 8 °0 tø 00 C) tø NT (Ν ¡2 42 o *-Qj £» •S· O o i/) i . o .Ol U. II ^ r ii C UJ ■o E I—— b 1« "Öl α I >^ NI- C) Ό <\| tø Ό tø NT Q Ο tø tø ΝΙ-Ο 240 220 200 180 ISO HO 120 100 80 60 40 20 ι 1 άσ Γ/ηο] dílL[sr\ V Α Εη = 2.19 MeV h k \ \ ι \ » E„= 2.30 MeV h 20 40 60 80 100 120 140 160 20 40 60 80 100 120 140 160 Fig. 3 Elastic scattering of neutrons from Li in the Lab system. Solid curves are the best fits through corrected experimental points. 1.6 -1.4 U IO 0.6 0.6 0.4 02 4 q* w I (Mí ii i i } Ί Τ ff f Η , h i H *l t J • Η ' τ . » / f ' i E„[MeV\ 0.5 10 Fig. 4 Integrated elastic cross sections. • present work © Lane et al. (6) 15 20 2.5 *■'&> TO THE READER EiJXIi All Euratom reports are announced, as and when they are issued, in the monthly periodical EURATOM INFORMATION, edited by the Centre for Information and Documentation (CID). For subscription (1 year : US$ 15, £ 5.7) or free specimen copies *BB$5Bffi:" ...TX- f *ît.t.t.!^,î* iJi Handelsblatt GmbH "Euratom Information Postfach 1102 please write 'liliiiiPliSÉl^ mmmm D-4 Düsseldorf (Germany) apœiifPiÉAI Office central de , des Corn* m IIS ÎrWBrSÎHï liUlii general prosperity and not individual riches — and with prosperity ¡1 disappears the greater part of the evil which is our heritage from jjjjjjpj: darker times. w i i i i r ί 8ρ8ΗΙ • -VV ¡rttöi «IS KR B™EÍpl^PfflP™i Mi l I ÀM'WÏ' All Euratom reports are on sale at the offices listed below, at the prices given on the back of the front cover (when ordering, specify clearly the EUR number and the title of the report, which are shown on the front covert. M J il till'ill )OFFICE CENTRAL DE VENTE DES PUBLICATIONS DES COMMUNAUTES EUROPEENNES 2, place de Metz, Luxembourg (Compte chèque pc ¡Mm UXEMBOURG OFFICE CENTRAL DE VENTE DES PUBLICATIONS DES COMMUNAUTES EUROPEENNES 

Elastic Scattering of Neutrons from 6Li. EUR 3454.

; í™EPii 
EUR 345; 
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STIC SCATTERING OF NEUTRON! 
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Joint Nuclear Research Center 
Geel Establishment - Belgium ïiiHïLiS'ttPr entrai Bureau for Nuclear Measurements - CBNM 
Mm 
■ ; : . ' , , 
I ¡'M 
iSISiìlLlili 
This document was prepared under the sponsorship of 
Commission of the European Atomic Energy Community 
(EURATOM). 
Neither the EURATOM Commission, its contractors nor any 
person acting on their behalf : 
ΐί£?1β^^ίΓ#Λι' 'V ■ troais 
Make any warranty or representation, ~ 
respect to the accuracy, completeness, or usefulness of the 
information contained in this document, or tha t the use of any 
information, apparatus, method, or process disclosed in this 
•M 
resulting from the use of any information, apparatus, method 
or process disclosed in this document. 
» t i » 
at the addresses listed on cover page 4 
a t the price of F F 2.50 FB 25, DM2.- Lit. 310 Fl. 1.80 
Λ When ordering, please quote the EUR number and which are indicated on the cover of each report. 
was 
Printed by L. Vanmelle 
Brussels, April 1967 
ΒΪΑΒΓ 
Droduced on the basis of the best available 
■» -inwoi'tíHaíi[fornir m ni » 
EUR 3454.e 
E L A S T I C S C A T T E R I N G O F N E U T R O N S FROM 6 L l 
by H.-H. KNITTER and M. COPPOLA 
European Atomic Energy Community — EURATOM 
Joint Nuclear Research Center — Geel Establ ishment (Belgium 
Central Bureau for Nuclear Measurements — CBNM 
Brussels, April 1967 — 14 Pages — 4 Figures — FB 25 
Angular distributions of neutrons elastically scattered from Li 
were measured in the energy region between 1.0 and 2.3 MeV using 
a fas t neutron time-of-flight spectrometer. F lux at tenuat ion and shape 
corrections were calculated and the final da ta a re presented in the 
form of coefficients of Legendre polynomial expansions. 
EUR 3454.e 
E L A S T I C S C A T T E R I N G O F N E U T R O N S FROM 6 L I 
by H.-H. KNITTER and M. COPPOLA 
European Atomic Energy Community — EURATOM 
Joint Nuclear Research Center — Geel Establ ishment (Belgium 
Central Bureau for Nuclear Measurements — CBNM 
Brussels, April 1967 — 14 Pages — 4 Figures — FB 25 
Angular distributions of neutrons elastically scattered from Li 
were measured in the energy region between 1.0 and 2.3 MeV using 
a fas t neutron time-of-flight spectrometer. Flux at tenuat ion and shape 
corrections were calculated and the final da ta a re presented in the 
form of coefficients of Legendre polynomial expansions. 
EUR 3454.e 
E L A S T I C S C A T T E R I N G OF N E U T R O N S FROM 6 L I 
by H.-H. KNITTER and M. COPPOLA 
European Atomic Energy Community — EURATOM 
Joint Nuclear Research Center — Geel Establ ishment (Belgium 
Central Bureau for Nuclear Measurements — CBNM 
Brussels, April 1967 — 14 Pages — 4 Figures — FB 25 
Angular distributions of neutrons elastically scattered from ^Li 
were measured in the energy region between 1.0 and 2.3 MeV using 
a fas t neutron time-of-flight spectrometer. F lux at tenuat ion and shape 
corrections were calculated and the final da ta are presented m the 
form of coefficients of Legendre polynomial expansions. 
6-

EUR 3454.e 
EUROPEAN ATOMIC ENERGY COMMUNITY - EURATOM 
ELASTIC SCATTERING OF NEUTRONS 
FROM 6Li 
by 
H.-H. KNITTER and M. COPPOLA 
1967 
Joint Nuclear Research Center 
Geel Establishment - Belgium 
Central Bureau for Nuclear Measurements - CBNM 
SUMMARY 
Angular distributions of neutrons elastically scattered from 6Li 
were measured in the energy region between 1.0 and 2.3 MeV using 
a fast neutron time-of-flight spectrometer. Flux attenuation and shape 
corrections were calculated and the final data are presented in the 
form of coefficients of Legendre polynomial expansions. 
- 3 -
Introduction 
A systematic study of neutron elastic scattering from Li was 
realized as a part of a program established to provide data 
needed for reactor design. Some time-of-flight measurements 
of neutron scattering from Li were previously accomplished 
(1-5), hut the data are spread over a large range of ener-
gies up to 14 MeV and do not provide a consistent set of ex-
perimental results. R.O.Lane et al. (6) have measured neutron 
differential cross sections of Li between 50 keV and 2.0 MeV 
using BF.J counters. A complete survey of the neutron cross 
sections of Li in the energy region 0.001 eV - 15 MeV exis-
ting up to July 1964 was made by E.D.Pendiebury (7). More 
recently R.O.Lane et al. have measured polarization and dif-
f( 7-erential cross sections for neutron scattering from Li and Li between 0.2 and 2,0 MeV using the same technique as be-
fore. 
In the energy region of the present measurements also the 
reaction Uii(n,dn')a with a Q-value of -1.47 MeV is energe-
tically possible. However, sinoe these neutrons have much 
longer flight times than the elastically scattered ones, 
they contribute to a region far from the elastic peak in 
the time spectra. In any case also at the highest primary 
neutron energy no appreciable contribution was observed 
from the Li(n,dn*)a reaction. 
Experimental equipment 
The measurements were performed at the 3 MeV Van de Graaf f 
accelerator of CBNM using a fast neutron time-of-flight 
spectrometer. The experimental equipment is the same used 
for earlier measurements and was already described (9). 
Neutrons were produced through the T(p,n)JHe reaction in 
occluded targets 1.0 and 0.6 mg/cm2 thick. The scattering 
samples were cylindrically shaped and enclosed in very 
thin aluminium containers. The contribution to the scatte-
ring due to the containers was experimentally subtracted 
using a dummy can. For best detection efficiency two diffe-
rent Li samples were used at different energies. 
Manuscript received on February 10, 1967. 
_ k -
Sample I: Height 2,59 cm; 0 3,67 cm; Weight (12,807 + 0,002)g 
Sample II: Height 4,98 cm; 0 3,68 cm; Weight (24,666 + 0,005)g. 
Both samples had an isotopie composition of 95,82$ Li and 
4,18# 7Li. 
Due to the sample-to-detector collimation two different scin­
tillators were also used, in conjunction with the above des­
cribed samples. 
Detector I: Stylbene crystal 1 3/4" 0 and 1" height 
Detector II: NE 102 A plastic scintillator 4" 0 and 1" height. 
In the case of Detector I the crystal was directly facing the 
photocathode of a 56 AVP tube, while for Detector II a light-
pipe of plexiglass was inserted between scintillator and pho­
tocathode. The relative efficiencies of both deteotors were 
obtained by comparison of the measured yield of neutrons scat­
tered from hydrogen at several angles with the known η-p dif­
ferential scattering cross sections (10). Proper beam attenu­
ation corrections in the hydrogenous sample were introduced. 
Experimental results 
Neutron scattering from Li was measured at several angles 
between 20° and 150°, but for some of the angular distribu­
tions the maximum scattering angle was reduced to 145° be­
cause of geometry limitations. 
Angular distributions of elastically scattered neutrons were 
measured at incident neutron energies of 1.00, 1.10, 1.20, 
1.33, 1.40, 1.50, 1.60, 1.70, 1.80, 1.90, 2.00, 2.09, 2.19 
and 2.30 MeV, with energy spreads, due to target thickness 
and finite geometry, of 62, 60, 59, 56, 54, 89, 87, 85, 83, 
81, 78, 76, 75 and 74 keV respectively. 
Por the absolute calibration of the cross sections, at each 
primary energy the neutron scattering from a polyethylene 
sample was measured at a certain angle. Absolute values of 
the differential cross sections were then obtained by COm-
parison of the angular distribution results on Li with the 
H(n,n)H differential cross section values. 
Corrections for finite geometry, beam attenuation and mul­
tiple scattering were calculated with the program MAGGIE (11), 
- 5 -
and the corrected differential cross section data were then 
fitted with a legendre polynomial expansion of the form 
7 
$#(*) = > B TP T(cos*). dfl 
^ 0 
The best fitting curves are presented in figs. 1, 2 and 3 
with the corrected experimental points. The values of the 
Β,- coefficients derived from the least squares fit proce­
dure are presented in table I, together with the computed 
errors, which are only of statistical nature. 
Overall errors on the absolute differential elastic croise 
sections are estimated to be around 5$. 
Integrated elastic scattering cross sections are presented 
in table II and fig. 4. The agreement with the previous 
results of R.O.Lane (6) is good. 
The theoretical interpretation of our scattering data on 6 7 Li and Li is unde 
future publication. 
r study and it will be the matter of a 
The authors wish to thank Dr. J.Spaepen, Director of CBNM, 
for supporting these measurements. The cooperation of 
Mr. B.Jay, Mr. C.Rousseau, the accelerator staff and the 
Sample Preparation Group is gratefully acknowledged. 
- 6 -
References 
1) C.Wong et al. Nucí. Phys. ¿¿ (1962) 680 
2) R.Batchelor and J.H.Towle Nucí. Phys. £7 (1963) 385 
3) P.Merchez et al. Compt. Rend. 260 (1965) 3922 
4) J.C.Hopkins LA-DC-7603 (1966) 
5) P.Merchez et al. Paris Conf. CN-23/75 (1966) 
6) R.O.Lane et al. Ann. Phys. V¿ (1961) 135 
7) E.D.Pendlebury AWRE 0-60/64 (1964) 
8) R.O.Lane e t a l . Phys. Rev. J J 6 (1964) Β 1710 
9) M.Coppola and H.-H.Kni t te r EUR 2798.e (1966) 
10) J.L.Gammel in Fas t Neutron Physics Par t I I , 
J.Wiley e Sons, New York and London (1963) 
11) J .B .Parker e t a l . Nucí. I n s t r . JiO (1964) 77 
TABLE I 
Values of the coefficients in the Legendre polynomial expansions in mb/sr 
(MeV) 
1 .00 
1 .10 
1 .20 
1 . 3 3 
1 . 4 0 
1 .50 
1 .60 
1 .70 
1 .80 
1 .90 
2 . 0 0 
2 . 0 9 
2 , 1 9 
2 . 3 0 
Bo 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
+ 
81 
8 2 
7 8 
7 6 
77 
7 6 
7 8 
81 
7 8 , 
84 
89 
9 5 
9 9 . 
105, 
, 4 2 + 1 
, 8 4 + 1 
. 4 6 + 1 
, 3 1 + 0 
, 9 9 + 0 
»99+p 
, 1 7 + 0 
7 4 + 0 
86+0 
, 7 0 + 0 
, 6 1 + 0 
. 3 8 + 0 
, 5 6 + 0 
20+0 
, 3 1 
. 4 0 
. 5 0 
. 2 7 
, 5 1 
, 7 3 
, 9 3 
. 3 7 
. 6 5 
, 4 7 
, 5 7 
, 7 6 
, 7 7 
, 6 9 
B 1 
+ 5 9 . 8 9 + 2 
+ 6 6 . 8 2 + 3 
+ 5 6 . 0 9 + 3 
+ 4 7 . 8 3 + 0 
+ 4 8 . 5 6 + 1 
+ 3 9 . 7 5 + 2 
+ 4 7 . 0 9 + 2 
+ 4 7 . 9 1 + 0 
+ 4 5 . 7 5 + 1 
+ 4 8 . 3 9 + 1 
+ 5 2 . 8 3 + 1 
+ 6 0 . 5 7 + 2 
+ 5 7 , 3 6 + 1 
+ 6 2 . 3 8 + 2 
. 3 6 
. 1 2 
. 1 6 
, 7 2 
. 2 1 
. 1 7 
, 64 
, 9 8 
, 5 5 
, 14 
27 
, 3 3 
, 94 
, 1 7 
B 2 
+27 
+ 19 
+20 
+ 14 
+20 
+ 18 
+ 12 
+ 14 
+ 10 
+ 1 3 . 
+ 15 , 
+26 
+27 
+36 
, 1 1 + 3 
. 3 0 + 4 
. 5 2 + 4 
. 9 6 + 0 
, 0 7 + 1 
. 3 3 + 3 
. 4 0 + 4 
. 5 9 + 1 
. 0 0 + 2 
89 + 1 
63+1 
. 8 9 + 3 
. 6 8 + 2 
, 7 2 + 3 
, 3 9 
, 7 1 
, 3 1 
, 9 7 
, 6 6 
. 1 1 
. 2 8 
30 
. 1 7 
, 6 3 
. 7 6 
, 3 9 
, 7 5 
. 0 2 
B 3 
+ 2 . 9 5 + 4 
- 0 . 6 6 + 6 , 
- 8 . 0 2 + 5 , 
- 1 . 5 4 + 1 
+ 3 . 1 5 + 2 
- 1 1 . 7 0 + 3 . 
+ 1 . 9 4 + 5 
- 5 . 3 0 + 1 
- 4 . 0 7 + 2 
+ 1 . 8 8 + 2 , 
+ 8 . 8 0 + 2 
+17.80+4, 
+ 1 2 0 1 + 3 
+15.76+4 
66 
. 0 3 
, 5 7 
, 0 6 
, 0 7 
, 9 7 
. 5 9 
. 5 6 
. 6 8 
10 
. 3 1 
, 5 3 
, 6 5 
, 3 2 
B 4 
+2 
- 0 
+3 
+2 
+4 
+8 
+6 
+2 
+2 
+ 1 
- 4 
+4 
+2 
+7 
, 2 0 + 4 
, 3 6 + 5 
, 6 7 + 5 
, 6 3 + 0 
»84+1 
, 6 2 + 3 
, 9 8 + 4 
. 4 7 + 1 
. 5 2 + 2 
, 3 0 + 1 
, 5 7 + 2 
, 5 3 + 3 
, 2 0 + 1 
, 9 2 + 3 
. 1 9 
. 1 1 
, 0 2 
. 8 8 
, 7 5 
. 6 4 
, 5 9 
, 3 2 
, 2 6 
, 4 4 
, 6 7 
, 8 7 
, 8 9 
. 9 1 
B 5 
- 1 . 1 9 + 6 . 
- 3 . 5 6 + 8 
- 7 . 8 0 + 7 
- 0 . 7 6 + 1 
- 1 . 0 5 + 2 
- 1 2 . 6 4 + 4 
+ 5 . 4 7 + 5 
- 3 . 3 2 + 2 
- 4 . 4 2 + 3 
- 1 . 5 2 + 3 
+ 5 . 9 1 + 2 
+12.41+4 
+ 6 . 9 1 + 3 
+ 4 . 6 1 + 4 
9 2 
.31 
. 3 1 
. 7 7 
. 9 2 
. 3 2 
. 5 8 
,10 
, 6 5 
. 1 6 
. 7 9 
, 7 9 
. 7 0 
. 5 0 
B 6 
- 0 
- 4 
+ 0 , 
+0 
- 0 
+7 
+0 
- 0 
- 0 
- 0 
+0 
+6 
+0 
+8 
0 3 + 0 
, 4 7 + 8 
, 8 6 + 7 
, 0 3 + 0 
. 1 2 + 0 
. 9 6 + 3 
. 2 8 + 6 
. 1 0 + 0 
. 1 1 + 0 
. 1 0 + 0 
, 0 2 + 0 
, 8 7 + 4 
, 7 0 + 1 
, 2 4 + 3 
. 0 6 
. 4 4 
, 8 5 
. 0 6 
. 0 3 
. 5 0 
. 4 4 
. 0 5 
. 0 5 
. 0 5 
. 0 6 
. 0 5 
. 0 0 
. 2 2 
B 7 
- 0 
- 7 
- 8 
- 0 
- 0 
- 1 
- 0 
- 0 
+0 
+0 
- 0 
+7 
+0 
+2 
, 0 8 + 0 . 0 6 
. 2 9 + 8 . 8 1 
. 2 9 + 8 . 7 0 
. 0 5 + 0 . 1 0 
. 0 3 + 0 . 0 3 
. 2 5 + 2 . 9 5 
. 4 7 + 6 . 5 8 
. 0 2 + 0 . 0 6 
. 0 5 + 0 . 0 5 
. 0 2 + 0 . 0 6 
. 1 3 + 0 . 0 6 
. 2 8 + 3 . 9 8 
, 8 4 + 1 . 0 6 
, 2 8 + 3 . 9 3 
I 
I 
TABLE II 
Integrated elastic cross sections 
(MeV)» 1.00 
= = = = = * = = = = = = 
σ β1 !! 1023 (mb) ¡I 
* a e l j{ 3 6 (mb) II 
II 
1.10 
1040 
36 
1.20 
======= 
985 
34 
1.33 
958 
33 
1.40 
:======: 
980 
34 
1.50 
:== = = = = : 
967 
34 
1.60 
_ 
982 
34 
1.70 1.80 
: = = = = = = | = = = = = = = 
1027 
36 
990 
35 
1.90 
: = = = = = = = 
1064 
37 
2 .00 
= = = = = = : 
1126 
39 
2.09 
======== 
1198 
42 
2 .19 
= = = = = = = 
1250 
44 
2 .30 
= = = = = 
1321 
46 
CO 
I 
Ζ 
ν»-
uf 
fe 
ι 
t-
Ci 
TDIT3 
I 
i l 
—ι 
Ό 
3 8 °0 tø 00 C) tø NT (Ν 
¡2 42 
o *-
Qj 
£» 
•S· 
O o i/) i . 
o 
.Ol 
U. 
II 
^ r 
ii 
C 
UJ 
■o 
E 
I—— 
b 1« "Öl α 
I 
>^ 
NI- C) Ό 
<\| 
tø Ό tø NT Q Ο tø tø ΝΙ-
Ο 
240 
220 
200 
180 
ISO 
HO 
120 
100 
80 
60 
40 
20 
ι 1 
άσ Γ/ηο] 
dílL[sr\ 
V 
Α 
Εη = 2.19 MeV 
h 
k 
\ 
\ ι 
\ » 
E„= 2.30 MeV 
h 
20 40 60 80 100 120 140 160 20 40 60 80 100 120 140 160 
Fig. 3 Elastic scattering of neutrons from Li in the Lab system. 
Solid curves are the best fits through corrected experimental points. 
1.6 -
1.4 
U 
IO 
0.6 
0.6 
0.4 
02 
4 
q* w 
I (Mí ii i i } 
Ί Τ ff f Η , h i H *
l t J 
• Η ' τ 
. » / 
f ' i 
E„[MeV\ 
0.5 10 
Fig. 4 Integrated elastic cross sections. 
• present work 
© Lane et al. (6) 
15 20 2.5 
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