ENTRY L0251 20190521 L042L025100000001 SUBENT L0251001 20190521 L042L025100100001 BIB 13 71 L025100100002 TITLE Photoneutron and photofission cross sections for 238U L025100100003 and 232Th using neutron capture gamma rays L025100100004 AUTHOR (W.J.Varhue,T.G.Williamson) L025100100005 INSTITUTE (1USAVIR) L025100100006 REFERENCE (J,ARI,38,561,1987) L025100100007 #NSR: 1987VA18 L025100100008 FACILITY (REAC,1USAVIR) The Tangential Beam Port Facility of theL025100100009 University of Virgina Reactor L025100100010 INC-SOURCE The photons produced in the neutron capture reaction ofL025100100011 nine different targets were used to give an energy L025100100012 range of 5-l1 MeV. The targets, the energies of their L025100100013 principal photons(Eg), their relative intensities(I) L025100100014 and the total number of photons(N) presented. L025100100015 (MPH=(16-S-0(N,G))) Eg=5.4 MeV,I=0.16,N=18 L025100100016 (MPH=(27-CO-59(N,G)27-CO-60)) Eg=6.7 MeV,I=0.1,N=132 L025100100017 (MPH=(22-TI-0(N,G))) Eg=6.7 MeV,I=0.44,N=84 L025100100018 (MPH=(26-FE-0(N,G))) Eg=7.6 MeV,I=0.52,N=187 L025100100019 (MPH=(13-AL-27(N,G)13-AL-28)) Eg=7.7 MeV,I=0.35,N=76 L025100100020 (MPH=(29-CU-0(N,G))) Eg=7.9 MeV,I=0.32,N=130 L025100100021 (MPH=(24-CR-0(N,G))) Eg=8.8 MeV,I=0.25,N=63 L025100100022 (MPH=(28-NI-0(N,G))) Eg=9.0 MeV,I=0.38,N=120 L025100100023 (MPH=(7-N-0(N,G))) Eg=10.8 MeV,I=0.12,N=36 L025100100024 The maximum energy spacing is 40 keV and the average L025100100025 spacing is 10 keV. L025100100026 SAMPLE The uranium and thorium targets weighed 10 g each. L025100100027 METHOD (EXTB) L025100100028 Three physical processes were identified that could L025100100029 lead to systematic errors. These are spontaneous L025100100030 fission, thermal neutron fission in 235U and L025100100031 attenuation of fragments in the oxide layer of the 238UL025100100032 foil. A calculation for both 238U and 232Th with L025100100033 spontaneous fission half-lives of 1.02e16 y and L025100100034 1.39e18 y would account for only 0.072% and 0.00053% ofL025100100035 the expected number of fission events. To estimate L025100100036 thermal neutron fission in 235U, 93% enriched 235U foilL025100100037 was placed in the beam produced by a Cr target in a L025100100038 manner identical to that of the depleted 238U foil. TheL025100100039 resulting track density did not vary by more than one L025100100040 standard deviation from the results obtained with the L025100100041 depleted 238U foil. To estimate attenuation of fission L025100100042 fragments in the black oxide layer, two separate runs L025100100043 were made in gamma ray beams produced by the Cr and Ti L025100100044 targets with a uranium foil that had its oxide layer L025100100045 removed. The results from these two runs did not L025100100046 deviate from the other results by more than one L025100100047 standard deviation. L025100100048 state nuclear track detectors, the photoneutrons L025100100049 from (gamma,n) and (gamma,f) reactions were detected L025100100050 by 4pi long counter of a Halpern type with 4 BF3 L025100100051 detectors immersed in paraffin. The efficiency of the L025100100052 detector was determined by placing a 1.0Ci PuBe source L025100100053 and was calculated to be 2.15%. L025100100054 DETECTOR (TRD,BF3) The fission events are recorded with solid L025100100055 state nuclear track detectors, the photoneutrons L025100100056 from (gamma,n) and (gamma,f) reactions were detected L025100100057 by 4pi long counter of a Halpern type with 4 BF3 L025100100058 detectors immersed in paraffin. The efficiency of the L025100100059 detector was determined by placing a 1.0Ci PuBe source L025100100060 and was calculated to be 2.15%. L025100100061 (GELI) For determination of contributions of water L025100100062 and Al to the capture gamma ray spectra. L025100100063 The intensity of the beam was monitored with LiF L025100100064 thermoluminescent dosimeters. L025100100065 ERR-ANALYS (DATA-ERR) No information on sources of uncertainties L025100100066 CORRECTION The background of the system was taken with each changeL025100100067 of the neutron capture target. To account for any L025100100068 potential scattering of neutrons in the beam by the L025100100069 fissile target, a copper foil of equal mass was placedL025100100070 in the detector during the background measurements. L025100100071 STATUS (CURVE) All figures were digitized by GSYS2.4.7. L025100100072 HISTORY (20190520C) OG. L025100100073 ENDBIB 71 0 L025100100074 NOCOMMON 0 0 L025100100075 ENDSUBENT 74 0 L025100199999 SUBENT L0251002 20190521 L042L025100200001 BIB 2 3 L025100200002 REACTION (92-U-238(G,X)0-NN-1,,SIG) L025100200003 The sum: (G,N)+(G,2N)+nu*(G,F) L025100200004 STATUS (CURVE) Fig. 5 in Appl.Radiat.Isot.,38,561,1987 L025100200005 ENDBIB 3 0 L025100200006 NOCOMMON 0 0 L025100200007 DATA 3 7 L025100200008 EN DATA DATA-ERR L025100200009 MEV MB MB L025100200010 5.00 17.4290 6.0812 L025100200011 6.00 23.0769 7.8541 L025100200012 6.99 40.0671 7.8368 L025100200013 8.00 80.6081 6.9763 L025100200014 8.98 169.1170 10.4702 L025100200015 10.01 361.4042 65.4086 L025100200016 11.00 581.6139 174.4365 L025100200017 ENDDATA 9 0 L025100200018 ENDSUBENT 17 0 L025100299999 SUBENT L0251003 20190521 L042L025100300001 BIB 2 2 L025100300002 REACTION (92-U-238(G,F),,SIG) L025100300003 STATUS (CURVE) Fig. 7 in Appl.Radiat.Isot.,38,561,1987 L025100300004 ENDBIB 2 0 L025100300005 NOCOMMON 0 0 L025100300006 DATA 3 7 L025100300007 EN DATA DATA-ERR L025100300008 MEV MB MB L025100300009 5.00 3.1242 0.4268 L025100300010 5.97 3.9065 0.7442 L025100300011 6.99 5.8568 0.8103 L025100300012 7.96 8.4193 1.0829 L025100300013 9.00 13.4094 2.9062 L025100300014 9.97 31.7212 5.4761 L025100300015 11.01 57.8016 5.4077 L025100300016 ENDDATA 9 0 L025100300017 ENDSUBENT 16 0 L025100399999 SUBENT L0251004 20190521 L042L025100400001 BIB 2 3 L025100400002 REACTION (90-TH-232(G,X)0-NN-1,,SIG) L025100400003 The sum: (G,N)+(G,2N)+nu*(G,F) L025100400004 STATUS (CURVE) Fig. 6 in Appl.Radiat.Isot.,38,561,1987 L025100400005 ENDBIB 3 0 L025100400006 NOCOMMON 0 0 L025100400007 DATA 3 7 L025100400008 EN DATA DATA-ERR L025100400009 MEV MB MB L025100400010 5.00 8.2853 3.9043 L025100400011 5.98 15.9565 3.0736 L025100400012 6.99 28.5618 6.3108 L025100400013 7.98 55.0223 6.7444 L025100400014 8.97 132.2140 8.5844 L025100400015 9.99 273.8033 65.0088 L025100400016 11.00 443.6076 134.9306 L025100400017 ENDDATA 9 0 L025100400018 ENDSUBENT 17 0 L025100499999 SUBENT L0251005 20190521 L042L025100500001 BIB 2 2 L025100500002 REACTION (90-TH-232(G,F),,SIG) L025100500003 STATUS (CURVE) Fig. 8 in Appl.Radiat.Isot.,38,561,1987 L025100500004 ENDBIB 2 0 L025100500005 NOCOMMON 0 0 L025100500006 DATA 3 5 L025100500007 EN DATA DATA-ERR L025100500008 MEV MB MB L025100500009 5.00 1.0442 0.2485 L025100500010 5.99 4.7934 0.3068 L025100500011 6.98 6.2617 0.5264 L025100500012 7.98 6.6334 0.6870 L025100500013 9.00 9.1838 0.6727 L025100500014 ENDDATA 7 0 L025100500015 ENDSUBENT 14 0 L025100599999 ENDENTRY 5 0 L025199999999