ENTRY 23618 20250221 23212361800000001 SUBENT 23618001 20250221 23212361800100001 BIB 18 72 2361800100002 TITLE Measurements of neutron capture cross-section for 2361800100003 nuclides of interest in decommissioning (II): 2361800100004 58Fe(n,gamma) 59Fe 2361800100005 AUTHOR (S.Nakamura,Y.Shibahara,S.Endo,G.Rovira,A.Kimura) 2361800100006 INSTITUTE (2JPNJAE,2JPNKTO) 2361800100007 REFERENCE (J,NST,62,300,2025) 2361800100008 #doi:10.1080/00223131.2024.2427244 2361800100009 FACILITY (REAC,2JPNKTO) 2361800100010 Kyoto University Research Reactor (KUR) . 2361800100011 INC-SOURCE (REAC)The graphite thermal column (TC-Pn) in KUR. The 2361800100012 nominal neutron flux intensity of TC-Pn is 2.84E+11 2361800100013 (n/cm2/sec) at 5 MW power operation. The AUTHORs 2361800100014 confirmed that the TC-Pn was well thermalized on the 2361800100015 basis of Westcott convention using neutron flux 2361800100016 monitors: Au-197, Co-59, and Mo-98. (See Fig. 3 in 2361800100017 the REFERENCE.) 2361800100018 SAMPLE (26-FE-58,NAT=0.00282) 2361800100019 Sample: Fe-nat metal foil 5.208+-0.001 mg 2361800100020 Monitor: Co-nat metal foil 0.640+-0.001 mg 2361800100021 Mo-nat metal wire 15.378+-0.001 mg 2361800100022 Au/Al Alloy wire 3.114+-0.001 mg 2361800100023 The sample and the monitors were irradiated 2361800100024 in the TC-Pn for 1 hour under 5-MW power operation. 2361800100025 DETECTOR (HPGE) High purity germanium detector, relative 2361800100026 efficiency of 25%. 2361800100027 The gamma-ray peak efficiencies of the Ge detector 2361800100028 were measured using a Eu-152 source and a mixed source 2361800100029 AM-8140 (Am-241, Cd-109, Co-57, Ce-139, Hg-203, Sn-113,2361800100030 Cs-137, Co-60 and Y-88) . 2361800100031 The uncertainty in the source radioactivity was 1.5% 2361800100032 for both of the standard sources. 2361800100033 METHOD (ACTIV,GSPEC) Based on Westcott convention method. 2361800100034 Because the neutron flux in the TC-Pn is well 2361800100035 thermalized, epithermal component in Westcott 2361800100036 convention method was negligibly small. 2361800100037 ANALYSIS The reaction rate of Fe-58 was obtained from 2361800100038 the yield of each decay gamma ray emitted from the 2361800100039 irradiated Fe sample. 2361800100040 The thermal-neutron flux was derived using the reaction2361800100041 rates and the thermal cross sections of the monitors. 2361800100042 The derived flux was (2.6832+-0.0424)E+10(n/cm2/sec) . 2361800100043 The cross section of Fe-58 was derived from the 2361800100044 reaction rate of Fe-58 and the thermal-neutron flux. 2361800100045 The thermal capture cross sections for monitors and 2361800100046 the g-factors were taken from the REL-REF. 2361800100047 For Mo-98, the thermal capture cross section was taken 2361800100048 from an AUTHOR's unpublished previous measurement. 2361800100049 COMMENT AUTHOR's assumed cross section of Mo-98, 0.132+-0.006 b2361800100050 is close to that given in REL-REF (0.130+-0.06 b) . 2361800100051 CORRECTION Self-shielding coefficients for thermal neutrons were 2361800100052 calculated from neutron capture cross-sections and 2361800100053 area densities of the sample and the monitors. 2361800100054 The coincidence summing effect was estimated from the 2361800100055 peak-to-total ratios and the peak efficiencies. 2361800100056 DECAY-DATA (26-FE-59,44.494D,DG,1099.24,0.5651, 2361800100057 DG,1291.59,0.4323) 2361800100058 (79-AU-198-G,2.6943D,DG,411.80,0.9562) 2361800100059 (27-CO-60-G,5.2711YR,DG,1173.24,0.9985, 2361800100060 DG,1332.49,0.99826) 2361800100061 (42-MO-99,2.7479D,DG,739.50,0.1212) 2361800100062 ASSUMED Thermal capture cross sections of the monitors were 2361800100063 assumed to be well known to determine the thermal 2361800100064 neutron flux. 2361800100065 (ASSUM1,79-AU-197(N,G)79-AU-198,,SIG) 2361800100066 (ASSUM2,27-CO-59(N,G)27-CO-60,,SIG) 2361800100067 (ASSUM3,42-MO-98(N,G)42-MO-99,,SIG) 2361800100068 ERR-ANALYS (ASSUM1-ERR) Uncertainty of Au-197 thermal C.S. 2361800100069 (ASSUM2-ERR) Uncertainty of Co-59 thermal C.S. 2361800100070 (ASSUM3-ERR) Uncertainty of Mo-98 thermal C.S. 2361800100071 REL-REF (R,,S.F.Mughabghab,B,NEUT.RES,,,2018) 2361800100072 STATUS (APRVD) Proofread by Shoji Nakamura. (2025-02-21) 2361800100073 HISTORY (20250221C) By A.Kimura. 2361800100074 ENDBIB 72 0 2361800100075 COMMON 6 3 2361800100076 ASSUM1 ASSUM1-ERR ASSUM2 ASSUM2-ERR ASSUM3 ASSUM3-ERR 2361800100077 B B B B B B 2361800100078 98.65 0.09 37.18 0.06 0.132 0.0062361800100079 ENDCOMMON 3 0 2361800100080 ENDSUBENT 79 0 2361800199999 SUBENT 23618002 20250221 23212361800200001 BIB 3 16 2361800200002 REACTION (26-FE-58(N,G)26-FE-59,,SIG) 2361800200003 ERR-ANALYS (ERR-T) Total uncertainty. 2361800200004 (ERR-S) Statistical uncertainty. 2361800200005 (3.6630+-0.0214)E-13 (event/s) 2361800200006 (ERR-1) Uncertainty due to half life of Sc-46. 2361800200007 (ERR-2) Uncertainty due to gamma-ray emission 2361800200008 probability. 2361800200009 (ERR-3) Uncertainty due to relative gamma-ray 2361800200010 efficiency of the Ge-detector. 2361800200011 (ERR-4) Uncertainty due to sample weight. 2361800200012 (ERR-5) Uncertainty due to sample purity. 2361800200013 (ERR-6) Uncertainty due to irradiation time. 2361800200014 (ERR-7) Uncertainty due to isotopic abundance. 2361800200015 (ERR-8) Uncertainty due to the thermal neutron flux. 2361800200016 (2.6832+-0.0133)E+11(n/cm2/sec) 2361800200017 STATUS (TABLE,,S.Nakamura+,J,NST,61,300,2024) Tables 5, 6, 7 2361800200018 ENDBIB 16 0 2361800200019 COMMON 9 6 2361800200020 ERR-S ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 2361800200021 ERR-6 ERR-7 ERR-8 2361800200022 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 2361800200023 PER-CENT PER-CENT PER-CENT 2361800200024 0.5842 0.0270 0.5486 0.1465 0.0192 0.01002361800200025 2.1277 0.0278 0.4957 2361800200026 ENDCOMMON 6 0 2361800200027 DATA 3 1 2361800200028 EN DATA ERR-T 2361800200029 MILLI-EV B B 2361800200030 25.3 1.36 0.03 2361800200031 ENDDATA 3 0 2361800200032 ENDSUBENT 31 0 2361800299999 ENDENTRY 2 0 2361899999999