ENTRY 21730 20230403 2173000000001 SUBENT 21730001 20230403 20231011 2173000100001 BIB 12 35 2173000100002 TITLE Precise determination of the branching ratio and 2173000100003 Q-value of the B-10(n,alpha)Li-7 reaction and of the 2173000100004 Q-value of the Li-6(n,alpha)H-3 reaction 2173000100005 AUTHOR (A.J.Deruytter,P.Pelfer) 2173000100006 REFERENCE (J,JNE,21,833,1967) Full report. 2173000100007 (P,EANDC(E)-76,140,1967) Progress rept, superseded. 2173000100008 INSTITUTE (2ZZZGEL) C.B.N.M. Geel. 2173000100009 FACILITY (REAC,2ZZZGEL) BR-1 reactor 2173000100010 INC-SOURCE (REAC) Thermal neutron beam extracted from the 2173000100011 graphite reflector, intensity 10*6 n/cm2/sec. 2173000100012 Cadmium ratio values were determined with and without 2173000100013 a 0.4 mm thick cadmium foil. 2173000100014 INC-SPECT Thermal Maxwellian neutron spectrum, with correction 2173000100015 made for an epi-cadmium plus room background 2173000100016 intensity equal to 2.80+-0.02% of the incident beam. 2173000100017 SAMPLE A thin elemental layer of B-10, 15 ug/cm2, with 2173000100018 a diameter of 38 mm, prepared by evaporation on a gold2173000100019 coated quartz disk, and mounted in a vacuum chamber a 2173000100020 at 30 mm from the sensitive surface of the detector. 2173000100021 METHOD (ASSOP) Detection of emitted alphas. Good separation 2173000100022 of the two alpha peaks allows the sum of counts under 2173000100023 each peak to be considered proportional to the two 2173000100024 partial cross sections to the Li-7 ground and first 2173000100025 excited states. 2173000100026 DETECTOR (SIBAR) Gold silicon surface barrier detector, 400 mm2 2173000100027 in area. The detector was outside the direct beam but 2173000100028 parallel to the source. 2173000100029 The detector was operated at a reverse bias of 20 V, 2173000100030 giving a depletion depth of 55 um, sufficient to 2173000100031 stop all reaction products of B-10(n,alpha) but thin 2173000100032 enough to limit pile up of background pulses. 2173000100033 STATUS (TABLE) Text on p.838 from J.Nucl.Energy,21(1967)833 2173000100034 HISTORY (19810130C) 2173000100035 (20230403A) SD:Updated to new date formats,lower case. 2173000100036 Corrections in all Subents. 2173000100037 ENDBIB 35 0 2173000100038 NOCOMMON 0 0 2173000100039 ENDSUBENT 38 0 2173000199999 SUBENT 21730002 20230403 20231011 2173000200001 BIB 4 15 2173000200002 REACTION ((5-B-10(N,A)3-LI-7,PAR,SIG)// 2173000200003 (5-B-10(N,A)3-LI-7,PAR,SIG)) 2173000200004 the branching ratio defined as sig(n,a(0))/sig(n,a(1))2173000200005 given in the text as percent, but converted here into 2173000200006 an absolute ratio. 2173000200007 CORRECTION Corrected for epithermal neutrons. The measured 2173000200008 reactor spectrum value was 6.741+-0.006%, and the 2173000200009 epicadmium value was 7.02+-0.08%. With the measured 2173000200010 cadmium ratio of the spectrum the value for epithermal2173000200011 neutrons and room background neutrons is given. 2173000200012 ERR-ANALYS (DATA-ERR) The uncertainty is one standard deviation, 2173000200013 primarily from statistical counting uncertainties. 2173000200014 The supplementary error from background was an order 2173000200015 of magnitude smaller. 2173000200016 HISTORY (20230403A) SD: REACTION code updated. ERR-T->DATA-ERR.2173000200017 ENDBIB 15 0 2173000200018 NOCOMMON 0 0 2173000200019 DATA 5 1 2173000200020 EN LVL-NUM-NM LVL-NUM-DN DATA DATA-ERR 2173000200021 EV NO-DIM NO-DIM NO-DIM NO-DIM 2173000200022 2.53E-02 0. 1. 6.733E-02 7.00E-05 2173000200023 ENDDATA 3 0 2173000200024 ENDSUBENT 23 0 2173000299999 ENDENTRY 2 0 2173099999999