ENTRY 13913 20240314 1391300000001 SUBENT 13913001 20240314 20240316 1391300100001 BIB 10 21 1391300100002 AUTHOR (J.A.Grundl) 1391300100003 TITLE Measurement of the Average Fission Cross-Section 1391300100004 Ratio, sigmaF(235U)/sigmaF(238U) for 235U and 239Pu 1391300100005 Fission Neutrons 1391300100006 REFERENCE (C,71VIENNA,,107,1971) 1391300100007 REL-REF (N,10304001,J.A.Grundl+,J,ANS,15,945,1972) 1391300100008 Measurements with 252Cf neutron source. 1391300100009 INSTITUTE (1USANBS) 1391300100010 FACILITY (REAC,1USANBS) 1391300100011 SAMPLE (92-U-235,ENR=0.997) Two foils: Enriched and natural 1391300100012 uranium, 200 microg/cm2 thick. 1391300100013 DETECTOR (IOCH) 1391300100014 MONITOR (92-U-235(N,F),,SIG) Run to run thermal neutron flux 1391300100015 levels in the cavity were monitored with a commercial 1391300100016 235U fission chamber exposed to a beam taken of the 1391300100017 front face of the thermal column. A triple scaler 1391300100018 arrangement was also used to record pulses from this 1391300100019 monitor chamber. 1391300100020 HISTORY (20140804C) BP 1391300100021 (20230604A) OS. Uncertainties modified in subs.2,3 1391300100022 (20240314A) On. Major alterations in 002. 1391300100023 ENDBIB 21 0 1391300100024 NOCOMMON 0 0 1391300100025 ENDSUBENT 24 0 1391300199999 SUBENT 13913002 20240314 20240316 1391300200001 BIB 7 20 1391300200002 REACTION ((92-U-235(N,F),,SIG,,FIS)/(92-U-238(N,F),,SIG,,FIS)) 1391300200003 STATUS (TABLE,,J.A.Grundl,C,71VIENNA,,107,1971) page 108. 1391300200004 METHOD (PHD) 1391300200005 INC-SOURCE Fission rates were observed with 235U fission 1391300200006 neutrons source. 1391300200007 INC-SPECT Energy of 235U fission neutrons is not listed in the 1391300200008 article. We can assume average fission neutrons 1391300200009 energy of ~2 MeV. 1391300200010 ERR-ANALYS (ERR-T) Uncertainties are due to: 1391300200011 (ERR-S) counting statistics - 0.3%. 1391300200012 (ERR-1) thermal column monitor stability - 0.6%. 1391300200013 (ERR-2) source-detector position - 2%. 1391300200014 (ERR-3) cavity position - 1.2%. 1391300200015 (ERR-4) reactor background - 2%. 1391300200016 (ERR-5) cavity return background - 2.5%. 1391300200017 (ERR-6) relative detector efficiency - 0.3%. 1391300200018 (ERR-7) intrinsic source-detector scattering - 1.5%. 1391300200019 (ERR-8) foil weight ratio - 2%. 1391300200020 HISTORY (20230604A) ERR-T in DATA section deleted 1391300200021 (20240314A) On. EN-DUMMY=2.0 MeV -> KT-DUMMY=1.32 MeV 1391300200022 ENDBIB 20 0 1391300200023 COMMON 10 6 1391300200024 ERR-T ERR-S ERR-1 ERR-2 ERR-3 ERR-4 1391300200025 ERR-5 ERR-6 ERR-7 ERR-8 1391300200026 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 1391300200027 PER-CENT PER-CENT PER-CENT PER-CENT 1391300200028 4.7 0.3 0.6 2.0 1.2 2.01391300200029 2.5 0.3 1.5 2.0 1391300200030 ENDCOMMON 6 0 1391300200031 DATA 2 1 1391300200032 KT-DUMMY DATA 1391300200033 MEV NO-DIM 1391300200034 1.32 3.71 1391300200035 ENDDATA 3 0 1391300200036 ENDSUBENT 35 0 1391300299999 SUBENT 13913003 20230707 20240316 1391300300001 BIB 8 23 1391300300002 REACTION (((92-U-235(N,F),,SIG,,FIS)/ 1391300300003 (92-U-238(N,F),,SIG,,FIS))// 1391300300004 ((92-U-235(N,F),,SIG,,FIS)/(92-U-238(N,F),,SIG,,FIS))) 1391300300005 STATUS (TABLE,,J.A.Grundl,C,71VIENNA,,107,1971) page 108. 1391300300006 METHOD (PHD) 1391300300007 INC-SOURCE Fission rates were observed with 235U (denominator 1391300300008 ratio) and 239Pu (nominator ratio) fission neutron 1391300300009 sources. 1391300300010 INC-SPECT Energies of 235U and 239Pu fission neutrons are not 1391300300011 listed in the article. We can assume that 235U and 1391300300012 239Pu average fission neutrons energies are ~2 and 1391300300013 ~2.1 MeV, respectively. 1391300300014 COMMENT From the knowledge of 235U fission source ratio of 1391300300015 3.71 and 239Pu/235U sources ratio of 9.70, one may 1391300300016 reconstruct a fission cross section ratio for a pure 1391300300017 239Pu source as 3.5987 +- 0.1704. 1391300300018 ERR-ANALYS (ERR-T) Uncertainties are due to: 1391300300019 (ERR-S) counting statistics - 0.4%. 1391300300020 (ERR-1) thermal column monitor stability - 0.6%. 1391300300021 (ERR-2) source-detector position - 0.7%. 1391300300022 (ERR-3) cavity position - 0.5%. 1391300300023 (ERR-4) reactor background - 0.6%. 1391300300024 HISTORY (20230604A) ERR-T in DATA section deleted 1391300300025 ENDBIB 23 0 1391300300026 COMMON 6 3 1391300300027 ERR-T ERR-S ERR-1 ERR-2 ERR-3 ERR-4 1391300300028 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 1391300300029 1.3 0.4 0.6 0.7 0.5 0.61391300300030 ENDCOMMON 3 0 1391300300031 DATA 3 1 1391300300032 EN-DUM-NM EN-DUM-DN DATA 1391300300033 MEV MEV NO-DIM 1391300300034 2.1 2.0 0.970 1391300300035 ENDDATA 3 0 1391300300036 ENDSUBENT 35 0 1391300399999 ENDENTRY 3 0 1391399999999