ENTRY 20894 20200805 22902089400000001 SUBENT 20894001 20200805 22902089400100001 BIB 12 68 2089400100002 TITLE Measurement of the Li-6(n,absorption) and 2089400100003 B-10(n,absorption) cross sections by the shell 2089400100004 transmission method 2089400100005 AUTHOR (S.A.Cox, F.R.Pontet) 2089400100006 REFERENCE (J,JNE,21,271,1967) final tables 2089400100007 (C,66WASH,,701,1966) 2089400100008 (P,WASH-1068,7,1967) Short descript., table 2089400100009 (P,WASH-1064,4,1965) Short descript., table 2089400100010 INSTITUTE (2UK ALD) A.W.R.E Aldermaston. 2089400100011 (1USAANL) S.A.Cox was a visitor at ALD from ANL. 2089400100012 FACILITY (VDG,2UK ALD) 3 MeV Van der Graaff. 2089400100013 INC-SOURCE (P-LI7) Li-7(p,n) reaction used as a neutron source 2089400100014 outside the sphere. 2089400100015 V-51(p,n) used as the source when inside the sphere. 2089400100016 Both methods were used to reduce the chance 2089400100017 of systematic errors in the corrections for 2089400100018 any one method affecting the results. 2089400100019 METHOD (SHELT) The spherical shell transmission method chosen 2089400100020 as the measurement is then independent of any 2089400100021 knowledge of the absolute neutron flux. 2089400100022 DETECTOR (BF3) 2089400100023 .For measurements using the Li-7 source, i.e. detector 2089400100024 inside the sample shell, a cadmium covered 2089400100025 BF-3 counter 4 cm in diameter was used at 1 atm. 2089400100026 .Using the V-51 source, i.e. detectors outside the 2089400100027 shell, seven paraffin wax moderated BF-3 counters 2089400100028 were used to integrate over neutron angular 2089400100029 distributions. These counters were 2.5 cm in diam. 2089400100030 and 12 cm long. 2089400100031 CORRECTION .Corrections were made for the following- 2089400100032 variation of detector efficiency with neutron energy. 2089400100033 Finite counter size and finite source-detector 2089400100034 distance for V-51 source only. 2089400100035 Non-perfect integration over angular distribution of 2089400100036 neutrons from V-51(p,n). 2089400100037 effects of anisotropic neutron emission from V(p,n). 2089400100038 multiple scattering and energy loss of neutrons in 2089400100039 each shell (calculated by Monte-Carlo and Carlson 2089400100040 transport methods for source inside shell, and by 2089400100041 Carlson transport alone for source outside shell). 2089400100042 ERR-ANALYS (ERR-T) The uncertainty given in the data tables is 2089400100043 the total error of a weighted average of all the 2089400100044 measurements. This total error is the sum in 2089400100045 quadrature of the partial components. 2089400100046 .With the V(p,n) neutron source, and a neutron energy 2089400100047 of 102 keV, the errors were- 2089400100048 counting error.............................. 4.4% 2089400100049 error due to uncertainty in background...... 1.0% 2089400100050 error due to non-perfect integration........ 1.3% 2089400100051 total error... 5.7% 2089400100052 .using the Li(p,n) neutron source, and a neutron energy2089400100053 of 102 keV, the errors were- 2089400100054 counting error.............................. 5.4% 2089400100055 error due to finite distance, counter size 2089400100056 and angular distribution corrections...... 1.0% 2089400100057 total error... 6.4% 2089400100058 .a further error due to the difference between the 2089400100059 results obtained with different neutron sources was 2089400100060 incorporated. 2089400100061 (ERR-1) error due to uncertainty in neutron energy 2089400100062 (ERR-2) error due to uncertainty in sigma(elastic) 2089400100063 STATUS (TABLE) Table from J.Nucl.En.,21(1967)271 2089400100064 HISTORY (19790425C) 2089400100065 (19810304A) error analysis revised. 2089400100066 (20200805U) SD:Updated to new date formats,lower case. 2089400100067 Ref. BAP,10,.. deleted (not relevant). ERR-ANALYS 2089400100068 updated. Small corrections in all Subents. The accuracy2089400100069 of data presentation has been revised. 2089400100070 ENDBIB 68 0 2089400100071 COMMON 2 3 2089400100072 ERR-1 ERR-2 2089400100073 PER-CENT PER-CENT 2089400100074 1. 3. 2089400100075 ENDCOMMON 3 0 2089400100076 ENDSUBENT 75 0 2089400199999 SUBENT 20894002 20200805 22902089400200001 BIB 5 11 2089400200002 REACTION (5-B-10(N,A)3-LI-7,,SIG) 2089400200003 SAMPLE Boron powder compacted by vibration between 0.005 2089400200004 inch thick copper shells. 2089400200005 Sphere was 10.21 cm inner diam., 12.06 cm out.diam. 2089400200006 COMMENT Results obtained agree closely with contemporary 2089400200007 figures of Mooring (priv comm) who measured 2089400200008 B-10(n,tot) and B-10(n,el) by independent method. 2089400200009 STATUS (TABLE) Table 4 from J.Nucl.Ener.,21(1967)271 2089400200010 HISTORY (19790425C) 2089400200011 (19810304A) REACTION and error analysis revised. 2089400200012 (20200805U) SD: STATUS updated. 2089400200013 ENDBIB 11 0 2089400200014 NOCOMMON 0 0 2089400200015 DATA 4 12 2089400200016 EN EN-ERR DATA ERR-T 2089400200017 KEV KEV B B 2089400200018 10.7 0.5 6.92 0.38 2089400200019 12.0 0.5 6.03 0.30 2089400200020 22.0 1.0 4.37 0.21 2089400200021 32.8 1.0 3.44 0.18 2089400200022 49.6 1.0 2.89 0.15 2089400200023 70.0 1.0 2.34 0.14 2089400200024 102.0 1.0 2.27 0.15 2089400200025 129.0 2.0 2.21 0.23 2089400200026 151.5 2.0 1.83 0.20 2089400200027 170.0 2.0 1.50 0.20 2089400200028 200.9 2.0 1.50 0.15 2089400200029 247.0 2.0 1.20 0.17 2089400200030 ENDDATA 14 0 2089400200031 ENDSUBENT 30 0 2089400299999 SUBENT 20894003 20200805 22902089400300001 BIB 5 14 2089400300002 REACTION (3-LI-6(N,T)2-HE-4,,SIG) 2089400300003 SAMPLE Li metal shells sandwiched between 0.010 inch 2089400300004 thick copper shells. 2089400300005 Large sphere 10.038 cm I.D., 20.364 Cm O.D. 2089400300006 Small sphere 10.038 cm I.D., 15.340 Cm O.D.. 2089400300007 COMMENT Assuming the Li-6(n,abs) cross section to Be equal 2089400300008 to the Li-6(n,t) cross section there is disagreement 2089400300009 between these results and the Li-6(n,t) measurements 2089400300010 of Schwarz et al (FOA 4 rapport.A 4393-411,Jan 1964) 2089400300011 at low energies. 2089400300012 STATUS (TABLE) Table 4 from J.Nucl.Ener.,21(1967)271 2089400300013 HISTORY (19790425C) 2089400300014 (19810304A) reaction and error analysis revised. 2089400300015 (20200805U) SD: STATUS updated. 2089400300016 ENDBIB 14 0 2089400300017 NOCOMMON 0 0 2089400300018 DATA 4 7 2089400300019 EN EN-ERR DATA ERR-T 2089400300020 KEV KEV B B 2089400300021 10.7 0.5 1.96 0.08 2089400300022 12.0 0.5 2.01 0.12 2089400300023 22.0 1.0 1.44 0.07 2089400300024 32.8 1.0 1.05 0.04 2089400300025 49.2 1.0 0.91 0.04 2089400300026 68.3 1.0 0.82 0.04 2089400300027 102.0 1.0 0.75 0.06 2089400300028 ENDDATA 9 0 2089400300029 ENDSUBENT 28 0 2089400399999 ENDENTRY 3 0 2089499999999