ENTRY 21205 20090110 22072120500000001 SUBENT 21205001 20090110 22072120500100001 BIB 13 41 2120500100002 INSTITUTE (2UK HAR) 2120500100003 REFERENCE (J,JNE,7,215,1958) 2120500100004 (R,AERE-R/R-2366,1958) 2120500100005 AUTHOR (J.A.Phillips) 2120500100006 TITLE -The (n,2n) cross-section of Th-232 for fission 2120500100007 neutrons- 2120500100008 INC-SOURCE (REAC) BEPO Reactor. 2120500100009 SAMPLE Decigram quantities of thorium nitrate. Sample placed 2120500100010 inside Cd cylinder to cut out thermal neutrons and 2120500100011 reduced the amount of Th-232 produced. 2120500100012 Ammonium sulphate was irradiated with thorium nitrate 2120500100013 to measure total fission neutron flux received. 2120500100014 METHOD (ACTIV) Irradiations of sample carried out in hollow 2120500100015 fuel element. Low energy gamma activity of Th- 2120500100016 (CHSEP) 231 measured after separation of Th-233 and 2120500100017 fission products from irradiated sample. 2120500100018 DETECTOR (PROPC) Krypton filled proportional counter. 2120500100019 Efficiency for 25.6 keV gammas found using 2120500100020 sample of known mass of U-235 in the sample 2120500100021 position and counting 25.6 keV peak. 2120500100022 Am-241 sources were also used for calibration. 2120500100023 (GEMUC) Liquid Geiger counter to measure monitor 2120500100024 activity. 2120500100025 DECAY-DATA (90-TH-231,25.6HR,DG,25.6) 2120500100026 MONITOR ((MONIT)16-S-32(N,P)15-P-32,,SIG,,FIS)Ammonium sulphate2120500100027 solution placed in fuel can with sample and 2120500100028 dissolved in water for counting. FISSION 2120500100029 Spectrum average cross-section for S-32 taken 2120500100030 as 60.3 mb (R.Richmond and J.A.Phillips,1958). 2120500100031 Used as flux monitor. 2120500100032 CORRECTION .Contribution of epi-cadmium neutrons neglected. 2120500100033 .Distortion of fission spectrum due to elastic 2120500100034 scattering in the moderator and inelastic scattering 2120500100035 in fuel. Correction small for Th-232(N,2N) but larger 2120500100036 for flux monitor, about 1.5 % . 2120500100037 STATUS (NDD) From NEUDADA. 2120500100038 HISTORY (19791206T) 2120500100039 (19800110E) 2120500100040 (20090110U) M.M. BIB information was added. 2120500100041 Dates were corrected for 4-digits year. 2120500100042 Free text was corrected to be human-readable. 2120500100043 ENDBIB 41 0 2120500100044 COMMON 2 3 2120500100045 EN-DUMMY MONIT 2120500100046 MEV MB 2120500100047 1.5000E+00 6.0300E+01 2120500100048 ENDCOMMON 3 0 2120500100049 ENDSUBENT 48 0 2120500199999 SUBENT 21205002 20090110 22072120500200001 BIB 5 21 2120500200002 REACTION (90-TH-232(N,2N)90-TH-231,,SIG,,FIS) 2120500200003 INC-SPECT Fission spectrum. Flux at sample about 2.5E+11 2120500200004 n/cm**2/sec. 2120500200005 ANALYSIS Mean c-s was obtained from two values 12.5+-0.8 and 2120500200006 12.3+-0.8 mb, respectively for two measurements: 2120500200007 Integrated flux Mass of ThO2 Counting rate 2120500200008 10**15 n/cm**2 mg counts/min/mg 2120500200009 4.41+-0.2 3.8+-0.05 187+-3 2120500200010 5.7+-0.05 178+-3 2120500200011 6.13+-0.05 175+-1 2120500200012 10.3+-0.05 169.+-2 2120500200013 5.13+-0.2 2.75+-0.05 201+-4 2120500200014 4.36+-0.05 199+-3 2120500200015 4.47+-0.05 198+-2 2120500200016 8.88+-0.05 190+-2 2120500200017 11.17+-0.05 190+-1 2120500200018 In calculating cross-sections, allowance was made 2120500200019 for the effect of gamma-ray absorption in thorium and 2120500200020 U-235 deposits. 2120500200021 ERR-ANALYS (DATA-ERR) Not specified. 2120500200022 STATUS .Data from text of publication, p.219. 2120500200023 ENDBIB 21 0 2120500200024 NOCOMMON 0 0 2120500200025 DATA 2 1 2120500200026 DATA DATA-ERR 2120500200027 MB MB 2120500200028 1.2400E+01 6.0000E-01 2120500200029 ENDDATA 3 0 2120500200030 ENDSUBENT 29 0 2120500299999 ENDENTRY 2 0 2120599999999