ENTRY 10947 20200229 14641094700000001 SUBENT 10947001 20200229 14641094700100001 BIB 14 52 1094700100002 INSTITUTE (1USAMHG) 1094700100003 REFERENCE (C,79KNOX,,976,1979) 1094700100004 AUTHOR (D.J.Grady,G.T.Baldwin,G.F.Knoll) 1094700100005 TITLE Absolute fast fission cross section measurements on 1094700100006 Np-237 1094700100007 FACILITY (REAC,1USAMHG) University of Michigan Ford nuclear 1094700100008 reactor 1094700100009 INC-SOURCE (PHOTO) Photoneutron sources activated by reactor 1094700100010 thermal neutrons. La-Be for 770-keV neutrons, Na-Be 1094700100011 for 964-keV neutrons. 1094700100012 SAMPLE Two platinum foils with 1-milligram/sq-cm deposit of 1094700100013 NpO(2). Deposit radius was 1.375-cm. 1094700100014 DETECTOR (TRD) Polyester track etch detector 1094700100015 MONITOR Reference Cf-252 spontaneous fission source used to 1094700100016 determine absolute photoneutron source strength. 1094700100017 METHOD (MANGB) Manganese bath used to determine absolute 1094700100018 photoneutron source strength. 1094700100019 Two sample foils positioned in dual compensated beam 1094700100020 geometry. Two runs with 10 and 14-cm spacing between 1094700100021 foils averaged to obtain cross section. Fission 1094700100022 targets, detectors, and neutron sources placed in 1094700100023 evacuated containment package which was suspended in 1094700100024 the center of a shielded low albedo room. Computer 1094700100025 code used to calculate scalar neutron flux and 1094700100026 aperture detection efficiency. 1094700100027 CORRECTION Three major corrections made: 1094700100028 -Manganese bath corrected for: 1094700100029 -source and dry well self-absorption 1094700100030 -leakage of neutrons from bath 1094700100031 -neutron streaming losses from dry well opening 1094700100032 -photo-activation of natural deuterium content of 1094700100033 bath 1094700100034 -parasitic fast neutron capture by O-16,and S-32 1094700100035 Corrections were -0.333% (770-keV) and 1094700100036 -0.555% (964-keV) 1094700100037 -Neutron inscattering from experimental apparatus, 1094700100038 dependent upon foil spacing 1094700100039 -10-cm spacing +4.100% (770 keV) and 1094700100040 +3.250% (964 keV) 1094700100041 -14-cm spacing +5.390% (770 keV) and 1094700100042 +4.380% (964 keV) 1094700100043 -Correction for finite neutron energy distribution of 1094700100044 sources, +17.350% (770 keV) and +6.860% (964 keV). 1094700100045 STATUS (PRELM) 1094700100046 (APRVD) Approved by D.J.Grady, 81/6/18. 1094700100047 (TABLE) Table II, Conf.on Nucl.Cross Sections f.Techn.,1094700100048 Knoxville 1979, p.976 1094700100049 ERR-ANALYS No information 1094700100050 HISTORY (19810210C) 1094700100051 (19810720A) Status added. 1094700100052 (20200226U) OS. STATUS updated, converted to 1094700100053 lower case, minor BIB changes 1094700100054 ENDBIB 52 0 1094700100055 NOCOMMON 0 0 1094700100056 ENDSUBENT 55 0 1094700199999 SUBENT 10947002 19810225 00001094700200001 BIB 1 1 1094700200002 REACTION (93-NP-237(N,F),,SIG) 1094700200003 ENDBIB 1 0 1094700200004 NOCOMMON 0 0 1094700200005 DATA 2 2 1094700200006 EN DATA 1094700200007 KEV B 1094700200008 770. 1.191 1094700200009 964. 1.365 1094700200010 ENDDATA 4 0 1094700200011 ENDSUBENT 10 0 1094700299999 ENDENTRY 2 0 1094799999999