ENTRY 41489 20020228 41404148900000001 SUBENT 41489001 20020228 41404148900100001 BIB 14 76 4148900100002 TITLE Investigation of multiplicity spectra and neutron 4148900100003 capture cross-sections of Th-232 in the energy region 4148900100004 21.5 - 215 eV. 4148900100005 AUTHOR (W.Y.BAEK,G.N.KIM,M.H.CHO,I.S.KO,W.NAMKUNG, 4148900100006 YU.V.GRIGORIEV,H.FAIKOV-STANCZYK, V.N.SHVETSHOV, 4148900100007 W.I.FURMAN) 4148900100008 INSTITUTE (4ZZZDUB) H.Fajkov-Stanczyk, V.Shvetshov, W.Furman - 4148900100009 Frank Laboratory of Neutron Physics. 4148900100010 (4RUSFEI) Yu.Grigoriev 4148900100011 (3KORPUE) W.Y.Baek,G.N.Kim,M.H.Cho,I.S.Ko,W.Namkung - 4148900100012 Pohang Accelerator Laboratiry, POSTECH. 4148900100013 REFERENCE (J,NIM/B,168,453,2000) Main Reference 4148900100014 FACILITY (REAC,4ZZZDUB) Reactor IBR-30 4148900100015 INC-SOURCE (REAC)IBR-30 pulsed neutron source. 4148900100016 Energy and Average Power of electron beam - 40 MeV and4148900100017 10 kW. Pulse Width amounted to 4 Microsec. 4148900100018 METHOD (TOF) Time-Of-Flight, Flight path 122 m 4148900100019 (GSPEC) Multiplicity Spectrometry 4148900100020 (COINC) Gamma time-of-flight spectra were obtained for 4148900100021 the coincidence multiplicities from 1 to 16. 4148900100022 DETECTOR (BF3) BF3 proportional counter -for neutron flux 4148900100023 monitoring. Placed in the beam. 4148900100024 Battery of three boron proportional counters of 0.5cm4148900100025 diameter and 6 cm length at the end of flight path - 4148900100026 to measure the neutron time-of-flight spectrum. 4148900100027 (STANK) 16-Section Liquid Scintillation Detector 4148900100028 Consisting of 86% Tholuol(C6H5CH3) and, 4148900100029 Enriched to 94% in B-10,14% Trimethilborate(B(OCH3)3).4148900100030 Liquid scintillator was contained in two 40 Liter 4148900100031 cylindrical tanks, each consisted of eight sections, 4148900100032 separated by 2 mm Aluminium. Each section was viewed 4148900100033 by FEU-100 photomultiplier. 4148900100034 Total gamma detection efficiency - about 30%. 4148900100035 SAMPLE 5.0 g thorium plate of size 4.5cm*4.5cm, 0.023cm 4148900100036 thickness (6.42E-4 atoms/barn). 4148900100037 13.24 g natural uranium disc of 6.0 cm diameter, 4148900100038 0.025cm thickness (1.19E-3 atoms/barn). 4148900100039 ANALYSIS (AREA) After subtraction of background, the areas of 4148900100040 resonances in gamma- time-of-flight spectrum were 4148900100041 determined for each coincidence multiplicity. 4148900100042 MONITOR (92-U-238(N,0),,EN) Resonances at 20.84, 66.02, 116.94 4148900100043 and 189.89 eV. 4148900100044 (92-U-238(N,TOT),,SIG) 4148900100045 (92-U-238(N,G)92-U-239,,SIG) 4148900100046 Cross-sections from ENDF/B-VI evaluated data library 4148900100047 CORRECTION Background subtraction. 4148900100048 For self-shielding and multiple scattering effects. 4148900100049 Correction factors for multiple scattering: 4148900100050 Th-232: U-238: 4148900100051 Resonance energy Factor Resonance energy Factor4148900100052 21.79 1.012 20.84 1.125 4148900100053 23.46 1.030 4148900100054 59.51 1.013 4148900100055 69.19 1.289 66.02 1.189 4148900100056 113.03 1.047 4148900100057 120.85 1.095 116.94 1.119 4148900100058 129.19 1.005 4148900100059 170.39 1.196 4148900100060 192.70 1.033 189.89 1.327 4148900100061 199.40 1.003 4148900100062 ERR-ANALYS (ERR-T) Total uncertainty 4148900100063 (ERR-S) Statistical uncertainty (0.7-4.0)% depending on4148900100064 the resonance area. 4148900100065 (ERR-1) Inaccuracy arising from the uncertainties in 4148900100066 the sample area, impurity and sample thickness.4148900100067 (ERR-2) Uncertainty due to gamma absorption neglect. 4148900100068 (ERR-3) Uncertainty due to the inaccuracy in correcting4148900100069 for the multiple scattering effect (0.1-1%) 4148900100070 depending on the resonance parameter. 4148900100071 (ERR-4) Uncertainty due inaccuracy in the energy 4148900100072 dependence of the neutron fux. 4148900100073 (ERR-5) Uncertainty in ratio of two counts due to 4148900100074 inaccuracy in incident neutron flux measuring. 4148900100075 (ERR-6) Uncertainty arising from inaccuracies in 4148900100076 background subtracting (1.-7.%). 4148900100077 HISTORY (20070228C) Compiled at CJD. M.M. 4148900100078 ENDBIB 76 0 4148900100079 COMMON 7 6 4148900100080 ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 ERR-6 4148900100081 ERR-S 4148900100082 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 4148900100083 PER-CENT 4148900100084 0.7 0.5 1. 0.5 3. 7. 4148900100085 4. 4148900100086 ENDCOMMON 6 0 4148900100087 ENDSUBENT 86 0 4148900199999 SUBENT 41489002 20070228 41404148900200001 BIB 2 4 4148900200002 REACTION (90-TH-232(N,G),,ARE) Radiative capture 4148900200003 cross-section for the resolved s resonances, 4148900200004 integrated over the resonance boundaries. 4148900200005 STATUS (TABLE) Data from Table 2 of Main Reference 4148900200006 ENDBIB 4 0 4148900200007 NOCOMMON 0 0 4148900200008 DATA 3 10 4148900200009 EN-RES DATA ERR-T 4148900200010 EV B*EV B*EV 4148900200011 21.79 371.6 12.5 4148900200012 23.46 572.7 19.2 4148900200013 59.51 252.6 10.1 4148900200014 69.19 877.8 30.3 4148900200015 113.03 346.9 16.0 4148900200016 120.85 407.9 16.5 4148900200017 129.19 90.0 8.1 4148900200018 170.39 398.2 19.9 4148900200019 192.70 232.5 18.8 4148900200020 199.40 152.1 12.7 4148900200021 ENDDATA 12 0 4148900200022 ENDSUBENT 21 0 4148900299999 SUBENT 41489003 20070228 41404148900300001 BIB 2 3 4148900300002 REACTION (90-TH-232(N,G)90-TH-233,,SIG,,AV) Radiative capture 4148900300003 cross-section averaged over energy range. 4148900300004 STATUS (TABLE) Data from Table 3 of Main Reference 4148900300005 ENDBIB 3 0 4148900300006 NOCOMMON 0 0 4148900300007 DATA 4 3 4148900300008 EN-MIN EN-MAX DATA ERR-T 4148900300009 EV EV B B 4148900300010 21.5 46.5 37.9 1.6 4148900300011 46.5 100. 21.1 1.0 4148900300012 100. 215. 13.8 0.9 4148900300013 ENDDATA 5 0 4148900300014 ENDSUBENT 13 0 4148900399999 ENDENTRY 3 0 4148999999999