ENTRY 10569 20131104 13951056900000001 SUBENT 10569001 20131104 13951056900100001 BIB 11 18 1056900100002 TITLE Subthreshold Fission Induced by Neutrons on 238U 1056900100003 AUTHOR (R.C.Block,R.W.Hockenbury,R.E.Slovacek,E.B.Bean, 1056900100004 D.S.Cramer) 1056900100005 REFERENCE (J,PRL,31,247,1973) 1056900100006 #doi:10.1103/PhysRevLett.31.247 1056900100007 INSTITUTE (1USARPI,1USAKAP) 1056900100008 FACILITY (LINAC,1USARPI) 1056900100009 INC-SOURCE (PHOTO) Photoneutrons from tantalum target. 1056900100010 METHOD (TOF) Time-of-flight over 10.1 meter flight path. 1056900100011 SAMPLE (92-U-238,ENR=1.0) The concentration of 235U was 1056900100012 27(6) ppm, less than 0.3 ppm of 233,234,236U. 1056900100013 DETECTOR (FISCH) Fission ionization chambers 1056900100014 STATUS (APRVD) Approved by author 1976/4/21. 1056900100015 HISTORY (19760126C) 1056900100016 (19830913A) converted to reaction formalism 1056900100017 (20040602A) converted to new date formats, lower case. 1056900100018 (20131104A) BP: Added doi, updated subentries, removed 1056900100019 subentry 6 with UNOBT status. 1056900100020 ENDBIB 18 0 1056900100021 NOCOMMON 0 0 1056900100022 ENDSUBENT 21 0 1056900199999 SUBENT 10569002 20131104 13951056900200001 BIB 4 7 1056900200002 REACTION 1(92-U-238(N,0),,EN) 1056900200003 2(92-U-238(N,F),,ARE) 1056900200004 ANALYSIS (AREA,SLA) The thin-sample approximation is used 1056900200005 for the integration of a Breit-Wigner single-level 1056900200006 resonance. 1056900200007 ERR-ANALYS2(DATA-ERR) No information on source of uncertainties. 1056900200008 STATUS (TABLE) Table I, page 249. 1056900200009 ENDBIB 7 0 1056900200010 NOCOMMON 0 0 1056900200011 DATA 3 2 1056900200012 DATA 1DATA 2DATA-ERR 2 1056900200013 EV B*EV B*EV 1056900200014 720. 0.31 0.08 1056900200015 1210. 0.11 0.03 1056900200016 ENDDATA 4 0 1056900200017 ENDSUBENT 16 0 1056900299999 SUBENT 10569003 20131104 13951056900300001 BIB 5 11 1056900300002 REACTION 1(92-U-238(N,0),,EN) 1056900300003 2(92-U-238(N,0),,L) 1056900300004 3(92-U-238(N,F),,WID) 1056900300005 ANALYSIS (SLA) Single level Breit-Wigner analysis. L=0 for s- 1056900300006 wave resonance. 1056900300007 ERR-ANALYS3(DATA-ERR) Primarily from the uncertainty of 235U 1056900300008 content of the 238U chambers. 1056900300009 ASSUMED (ASSUM,92-U-238(N,G),,WID) 1056900300010 Values calculated using assumed radiation width 1056900300011 of well I of the double-humped fission barrier. 1056900300012 STATUS (TABLE) Table I, page 249. 1056900300013 ENDBIB 11 0 1056900300014 COMMON 1 3 1056900300015 ASSUM 1056900300016 MILLI-EV 1056900300017 23. 1056900300018 ENDCOMMON 3 0 1056900300019 DATA 4 2 1056900300020 DATA 1DATA 2DATA 3DATA-ERR 3 1056900300021 EV NO-DIM MILLI-EV MILLI-EV 1056900300022 720. 0. 1.2 0.3 1056900300023 1210. 0. 0.12 0.03 1056900300024 ENDDATA 4 0 1056900300025 ENDSUBENT 24 0 1056900399999 SUBENT 10569004 20131104 13951056900400001 BIB 5 11 1056900400002 REACTION 1(92-U-238(N,0),,EN) 1056900400003 2(92-U-238(N,0),,L) 1056900400004 3(92-U-238(N,F),,WID) 1056900400005 ANALYSIS (SLA) Single level Breit-Wigner analysis. L=0 for s- 1056900400006 wave resonance. 1056900400007 ERR-ANALYS3(DATA-ERR) Primarily from the uncertainty of 235U 1056900400008 content of the 238U chambers. 1056900400009 ASSUMED (ASSUM,92-U-238(N,G),,WID) 1056900400010 Values calculated using assumed radiation width 1056900400011 of well II of the double-humped fission barrier. 1056900400012 STATUS (TABLE) Table I, page 249. 1056900400013 ENDBIB 11 0 1056900400014 COMMON 1 3 1056900400015 ASSUM 1056900400016 MILLI-EV 1056900400017 4.9 1056900400018 ENDCOMMON 3 0 1056900400019 DATA 4 2 1056900400020 DATA 1DATA 2DATA 3DATA-ERR 3 1056900400021 EV NO-DIM MILLI-EV MILLI-EV 1056900400022 720. 0. 0.29 0.07 1056900400023 1210. 0. 0.051 0.013 1056900400024 ENDDATA 4 0 1056900400025 ENDSUBENT 24 0 1056900499999 SUBENT 10569005 20131104 13951056900500001 BIB 7 12 1056900500002 REACTION (92-U-238(N,F),,SIG,,AV) 1056900500003 ERR-ANALYS (DATA-ERR) No information on source of uncertainties. 1056900500004 METHOD The 238U fission cross section is deduced from the 1056900500005 normalization. An auxiliary measurement was also 1056900500006 carried out with 235U (93% enriched) fission chamber in1056900500007 the same geometry to normalize the 238U subthreshold 1056900500008 fission cross section to the known 235U fission cross 1056900500009 section. 1056900500010 MONITOR (92-U-235(N,F),,SIG) 1056900500011 MONIT-REF (,,R,BNL-325,(3),1965) 1056900500012 STATUS (TABLE) Table II, page 250. 1056900500013 REL-REF (A,10290001,M.G.Silbert+,J,PR/C,4,220,1971) 1056900500014 ENDBIB 12 0 1056900500015 NOCOMMON 0 0 1056900500016 DATA 4 2 1056900500017 EN-MIN EN-MAX DATA DATA-ERR 1056900500018 KEV KEV MICRO-B MICRO-B 1056900500019 10. 30. 87. 26. 1056900500020 30. 100. 40. 12. 1056900500021 ENDDATA 4 0 1056900500022 ENDSUBENT 21 0 1056900599999 NOSUBENT 10569006 20131104 13951056900600001 ENDENTRY 6 0 1056999999999