ENTRY 30974 20090915 31413097400000001 SUBENT 30974001 20090915 31413097400100001 BIB 15 59 3097400100002 TITLE Measurement of absolute fission rate of natural 3097400100003 depleted uranium and thorium and microscopic cross 3097400100004 section ratios in the radial beam of the RA3. 3097400100005 AUTHOR (M.Bovisio de Ricabarra,L.Cohen de Porto,D.Walsman, 3097400100006 G.H.Ricabarra) 3097400100007 INSTITUTE (3ARGCNE) 3097400100008 REFERENCE (C,88MITO,,123,198806) 3097400100009 FACILITY (REAC,3ARGCNE) 3097400100010 SAMPLE 100 - 200 microgram/cm**2 thin deposits of natural- 3097400100011 and depleted-uranium-(23ppm U-235) oxide (U3O8) and 3097400100012 thorium-232 oxide (ThO2) were prepared by molecular 3097400100013 plating on polished aluminium disks as to ensure 3097400100014 adequate deposit uniformity. The masses were deter- 3097400100015 mined by alpha-counting assay (uranium) and gamma- 3097400100016 counting assay (thorium). 3097400100017 Indium-115: no further details are given of this 3097400100018 sample. 3097400100019 DETECTOR (FISCH,TRD,D4PI,GELI) A miniature fission chamber 3097400100020 and a solid-state nuclear track detector (SSNTD) for 3097400100021 fission fragment counting, a 4Pi-beta proportional 3097400100022 gas flow counter for determining the beta activity of 3097400100023 Mn-56 and a GeLi detector for measuring the gamma 3097400100024 activities of Mn-56 and In-115-m. The aluminium 3097400100025 electroplated deposit is the grounded kathode plate of 3097400100026 the fission chamber. In the SSNTD measurements the 3097400100027 deposits are placed in close contact with the mica 3097400100028 disks between a aluminium back plate and a ring holder.3097400100029 METHOD (EXTB,ACTIV) External beam irradiation of SSNTD and 3097400100030 fission chamber, activation measurement of the 3097400100031 In-115(n,n)In-115-m reaction relative to Mn monitor. 3097400100032 INC-SOURCE (REAC) Radial neutron beam of the RA3 research reactor 3097400100033 PART-DET (FF) 3097400100034 ANALYSIS (DECAY) For In-115(n,n)In-115-m reaction. 3097400100035 From the experimentally determined fission-rate 3097400100036 ratios: depleted uranium/natural uranium and 3097400100037 thorium-232/depleted uranium, and the In-115-m/Mn-56 3097400100038 cross section ratios the ratios presented in subents 3097400100039 002 - 005 were obtained. 3097400100040 CORRECTION Corrections have been made for fission fragment self- 3097400100041 absorption in the deposits, flux perturbation in 3097400100042 the neutron beam and ssntd stack absorption. 3097400100043 ERR-ANALYS (ERR-T) Errors are obtained by quadrature sum of 3097400100044 independent error components: 3097400100045 1) Statistics of fission product counting and 3097400100046 systematic errors in fission fragment absorption 3097400100047 corrections, the same for alphas in uranium mass 3097400100048 assay. 3097400100049 2) Statistics of gamma counting uncertainty 3097400100050 and self-absorption for thorium mass assay. 3097400100051 3) Statistics of gamma counting errors and gamma 3097400100052 efficiency calibrations for In-115-m/Mn56 ratio. 3097400100053 HISTORY (19920127C) HW 3097400100054 (19930922A) HW.-Status altered and 'Monitor' removed in3097400100055 sub 001, data in sub 002 corrected, sub 003 altered, 3097400100056 'Inc-spect' moved from sub 001 to sub 002 - 005.- 3097400100057 (19940308U) HW.-Correction in Decay-data of subent 002.3097400100058 (20090912A) SD:Updated to new date formats,lower case. 3097400100059 STATUS (TABLE) Data are taken from Tables 7 and 8 of Conf. on 3097400100060 Nuclear Data for Sci. and Technol.,Mito,1988,p.123. 3097400100061 ENDBIB 59 0 3097400100062 NOCOMMON 0 0 3097400100063 ENDSUBENT 62 0 3097400199999 SUBENT 30974002 20090915 31413097400200001 BIB 4 12 3097400200002 REACTION ((49-IN-115(N,INL)49-IN-115-M,,SIG,,SPA)/ 3097400200003 (25-MN-55(N,G)25-MN-56,,SIG,,SPA)) 3097400200004 DECAY-DATA (25-MN-56,2.5785HR,DG,847.,.989) 3097400200005 (49-IN-115-M,4.486HR,DG,336.) 3097400200006 INC-SPECT The neutron beam was assumed to have a Maxwellian 3097400200007 thermal component, a 1/E epithermal region and a fast 3097400200008 region with a neutron fission shape (200keV