ENTRY 10232 20201214 14751023200000001 SUBENT 10232001 20201214 14751023200100001 BIB 11 29 1023200100002 TITLE Measurements of the fission cross section ratio of 1023200100003 238U to 235U from 2-3 MeV 1023200100004 AUTHOR (W.P.Poenitz, R.J.Armani) 1023200100005 INSTITUTE (1USAANL) 1023200100006 REFERENCE (J,JNE,26,483,1972) 1023200100007 FACILITY (DYNAM,1USAANL) 1023200100008 INC-SOURCE (P-LI7) Li (50-100 keV thick) deposited on Ta backing 1023200100009 METHOD (TOF) Time-of-flight (2 nsec pulses, 10 and 20 cm 1023200100010 flight paths) for background suppression 1023200100011 DETECTOR (SCIN) Double chamber gas scintillation counter, with 1023200100012 each chamber viewed by two photomultipliers. 1023200100013 CORRECTION Corrected for 1023200100014 - 7Li(p,n1) neutron contributions 1023200100015 (~3.5% at 2 MeV, very small at 2.5 and 3 MeV), 1023200100016 - in-scattering from Ta backing 1023200100017 (largest at 2 MeV, but always less than 0.5%), 1023200100018 - Inelastic scattering in Mo backings and counters 1023200100019 (largest at 2 MeV but always less than 1%), 1023200100020 - fission of other isotopes 1023200100021 (small and accurately known). 1023200100022 Neutron flux differences (1-2%) were eliminated by 1023200100023 foil position interchange. 1023200100024 STATUS (APRVD) Approved by author. 1023200100025 HISTORY (19720117C) 1023200100026 (19730509A) BIB addition. 1023200100027 (19821015A) Converted to REACTION formalism 1023200100028 (20010309U) Updated to new date formats, lower case. 1023200100029 (20190722A) On. Major revisions in 002-006. 1023200100030 (20201214U) On. Minor revisions in 003 and 006. 1023200100031 ENDBIB 29 0 1023200100032 NOCOMMON 0 0 1023200100033 ENDSUBENT 32 0 1023200199999 SUBENT 10232002 20190722 14541023200200001 BIB 6 24 1023200200002 REACTION ((92-U-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1023200200003 SAMPLE Sample set I 1023200200004 (92-U-238,ENR=0.99985) 40 ug/cm2 thick 1023200200005 (92-U-235,ENR=0.99857) 35 ug/cm2 thick 1023200200006 ERR-ANALYS (ERR-T) Total uncertainty (2.3%)1023200200007 (ERR-S,,,U) Statistical uncertainty (1.6%)1023200200008 (ERR-1,,,F) Mass ratio (1.5%)1023200200009 (ERR-2,,,F) Secondary neutrons (0.2%)1023200200010 (ERR-3,,,F) Inscattering from target (0.2%)1023200200011 (ERR-4,,,F) Inelastic scattering (0.3%)1023200200012 (ERR-5,,,F) Fiss. frag. absorption extrapolation (0.3%)1023200200013 (ERR-6,,,F) Fission of other isotopes (0.1%)1023200200014 (ERR-7,,,F) Background (0.2%)1023200200015 COVARIANCE Poenitz assigns the following correlation coefficients 1023200200016 between 002, 003, 004 and 006: 1023200200017 1.0 for ERR-6, 1023200200018 0.8 for ERR-2, ERR-3, ERR-4, ERR-5, ERR-7. 1023200200019 STATUS (PENTZ) GMA input #816 1023200200020 (COREL,10232003) Measurement with Sample Set II 1023200200021 (COREL,10232004) Measurement with Sample Set III 1023200200022 HISTORY (19721220A) Value of ratio = 0.430+-0.009 as given in 1023200200023 preprint changed 1023200200024 (20010309A) Value corrected. 1023200200025 (20190722A) On. Revised with GMA input #816 1023200200026 ENDBIB 24 0 1023200200027 COMMON 7 6 1023200200028 ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 ERR-6 1023200200029 ERR-7 1023200200030 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 1023200200031 PER-CENT 1023200200032 1.5 0.2 0.2 0.3 0.3 0.1 1023200200033 0.2 1023200200034 ENDCOMMON 6 0 1023200200035 DATA 5 1 1023200200036 EN EN-RSL-HW DATA ERR-S ERR-T 1023200200037 MEV PER-CENT NO-DIM PER-CENT PER-CENT 1023200200038 2.5 3.0 0.430 1.6 2.3 1023200200039 ENDDATA 3 0 1023200200040 ENDSUBENT 39 0 1023200299999 SUBENT 10232003 20201214 14751023200300001 BIB 7 26 1023200300002 REACTION ((92-U-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1023200300003 SAMPLE Sample set II 1023200300004 By compiler (2019-07-22): 1023200300005 Enrichments in Table I of J.Nucl.Energy 26(1972)483 1023200300006 are most probably printed wrongly. 1023200300007 (92-U-238,ENR=0.96812) 50, 100 and 300 ug/cm2 thick 1023200300008 (92-U-235,ENR=0.98432) 50, 100 and 300 ug/cm2 thick 1023200300009 ANALYSIS Average over 3 samples 1023200300010 ERR-ANALYS (ERR-T) Total uncertainty (1.7%)1023200300011 (ERR-S,,,U) Statistical uncertainty (1.2%)1023200300012 (ERR-1,,,F) Mass ratio (1.0%)1023200300013 (ERR-2,,,F) Secondary neutrons (0.2%)1023200300014 (ERR-3,,,F) Inscattering from target (0.2%)1023200300015 (ERR-4,,,F) Inelastic scattering (0.3%)1023200300016 (ERR-5,,,F) Fiss. frag. absorption extrapolation (0.3%)1023200300017 (ERR-6,,,F) Fission of other isotopes (0.1%)1023200300018 (ERR-7,,,F) Background (0.2%)1023200300019 COVARIANCE Poenitz assigns the following correlation coefficients 1023200300020 between 002, 003, 004 and 006: 1023200300021 1.0 for ERR-6, 1023200300022 0.8 for ERR-2, ERR-3, ERR-4, ERR-5, ERR-7. 1023200300023 STATUS (PENTZ) GMA input #817 1023200300024 (COREL,10232002) Measurement with Sample Set I 1023200300025 (COREL,10232004) Measurement with Sample Set III 1023200300026 HISTORY (20190722A) On. Revised with GMA input #817 1023200300027 (20201214U) On. HISTORY corrected. 1023200300028 ENDBIB 26 0 1023200300029 COMMON 7 6 1023200300030 ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 ERR-6 1023200300031 ERR-7 1023200300032 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 1023200300033 PER-CENT 1023200300034 1.0 0.2 0.2 0.3 0.3 0.1 1023200300035 0.2 1023200300036 ENDCOMMON 6 0 1023200300037 DATA 5 1 1023200300038 EN EN-RSL-HW DATA ERR-S ERR-T 1023200300039 MEV PER-CENT NO-DIM PER-CENT PER-CENT 1023200300040 2.5 3.0 0.434 1.2 1.7 1023200300041 ENDDATA 3 0 1023200300042 ENDSUBENT 41 0 1023200399999 SUBENT 10232004 20190722 14541023200400001 BIB 6 21 1023200400002 REACTION ((92-U-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1023200400003 SAMPLE Sample set III 1023200400004 (92-U-238,ENR=0.99564) 300 ug/cm2 thick 1023200400005 (92-U-235,ENR=0.99993) 300 ug/cm2 thick 1023200400006 ERR-ANALYS (ERR-T) Total uncertainty (1.8%)1023200400007 (ERR-S,,,U) Statistical uncertainty (1.4%)1023200400008 (ERR-1,,,F) Mass ratio (1.0%)1023200400009 (ERR-2,,,F) Secondary neutrons (0.2%)1023200400010 (ERR-3,,,F) Inscattering from target (0.2%)1023200400011 (ERR-4,,,F) Inelastic scattering (0.3%)1023200400012 (ERR-5,,,F) Fiss. frag. absorption extrapolation (0.3%)1023200400013 (ERR-6,,,F) Fission of other isotopes (0.1%)1023200400014 (ERR-7,,,F) Background (0.2%)1023200400015 COVARIANCE Poenitz assigns the following correlation coefficients 1023200400016 between 002, 003, 004 and 006: 1023200400017 1.0 for ERR-6, 1023200400018 0.8 for ERR-2, ERR-3, ERR-4, ERR-5, ERR-7. 1023200400019 STATUS (PENTZ) GMA input #818 1023200400020 (COREL,10232002) Measurement with Sample Set I 1023200400021 (COREL,10232003) Measurement with Sample Set II 1023200400022 HISTORY (20190722A) On. Revised with GMA input #818 1023200400023 ENDBIB 21 0 1023200400024 COMMON 7 6 1023200400025 ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 ERR-6 1023200400026 ERR-7 1023200400027 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 1023200400028 PER-CENT 1023200400029 1.0 0.2 0.2 0.3 0.3 0.1 1023200400030 0.2 1023200400031 ENDCOMMON 6 0 1023200400032 DATA 5 1 1023200400033 EN EN-RSL-HW DATA ERR-S ERR-T 1023200400034 MEV PER-CENT NO-DIM PER-CENT PER-CENT 1023200400035 2.5 3.0 0.442 1.4 1.8 1023200400036 ENDDATA 3 0 1023200400037 ENDSUBENT 36 0 1023200499999 SUBENT 10232005 20190722 14541023200500001 BIB 5 9 1023200500002 REACTION ((92-U-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1023200500003 ANALYSIS Combination of the results with Sample set I, II, III 1023200500004 ERR-ANALYS (DATA-ERR) Errors mainly statistical plus mass ratio 1023200500005 uncertainties. 1023200500006 STATUS (TABLE) Table 2 of J.Nucl.Energy 26(1972)483 1023200500007 (DEP,10232002) Sample set I 1023200500008 (DEP,10232003) Sample set II 1023200500009 (DEP,10232004) Sample set III 1023200500010 HISTORY (20190722A) On. EN-RSL-HW added. 1023200500011 ENDBIB 9 0 1023200500012 NOCOMMON 0 0 1023200500013 DATA 4 1 1023200500014 EN EN-RSL-HW DATA DATA-ERR 1023200500015 MEV PER-CENT NO-DIM NO-DIM 1023200500016 2.5 3.0 0.435 0.007 1023200500017 ENDDATA 3 0 1023200500018 ENDSUBENT 17 0 1023200599999 SUBENT 10232006 20201214 14751023200600001 BIB 8 26 1023200600002 REACTION ((92-U-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1023200600003 MONITOR ((92-U-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1023200600004 SAMPLE (92-U-238,ENR=0.99985) 40 ug/cm2 thick (Sample set I) 1023200600005 (92-U-235,ENR=0.99857) 35 ug/cm2 thick (Sample set I) 1023200600006 (92-U-238,ENR=0.99564) 300 ug/cm2 thick(Sample set III)1023200600007 (92-U-235,ENR=0.99993) 300 ug/cm2 thick(Sample set III)1023200600008 ANALYSIS Average over 2 samples (Sample sets I and III) 1023200600009 normalized to 2.5 MeV value 1023200600010 ERR-ANALYS (ERR-T) Total uncertainty 1023200600011 (ERR-S,,,U) Statistics 1023200600012 (ERR-1,,,P) Secondary neutrons 1023200600013 (ERR-2,,,P) Inscattering from target 1023200600014 (ERR-3,,,P) Inelastic scattering (0.2%)1023200600015 (ERR-4,,,P) Fission fragment absorption 1023200600016 (ERR-5,,,P) FIssion of other isotopes (0.1%)1023200600017 (ERR-6,,,P) Background 1023200600018 (MONIT-ERR) Uncertainty in reference value at 2.5 MeV 1023200600019 COMMENT Comment by compiler (2019-07-22): 1023200600020 The following values are compiled as shape ratios 1023200600021 (instead of absolute raiots) in Poenitz's database: 1023200600022 0.4158 @ 2.0 MeV, 0.4286 @ 2.5 MeV, 0.4296 @ 3.0 MeV 1023200600023 STATUS (TABLE) Table 2 of J.Nucl.Energy 26(1972)483 1023200600024 (PENTZ) GMA input #819 for partial uncertainties 1023200600025 (DEP,10232005) Reference value at 2.5 MeV 1023200600026 HISTORY (20190722A) On. Revised with GMA input #819 1023200600027 (20201214U) On. STATUS and HISTORY corrected. 1023200600028 ENDBIB 26 0 1023200600029 COMMON 5 3 1023200600030 EN-NRM MONIT MONIT-ERR ERR-3 ERR-5 1023200600031 MEV NO-DIM NO-DIM PER-CENT PER-CENT 1023200600032 2.5 0.435 0.007 0.2 0.1 1023200600033 ENDCOMMON 3 0 1023200600034 DATA 9 2 1023200600035 EN EN-RSL-HW DATA ERR-T ERR-S ERR-1 1023200600036 ERR-2 ERR-4 ERR-6 1023200600037 MEV PER-CENT NO-DIM NO-DIM PER-CENT PER-CENT 1023200600038 PER-CENT PER-CENT PER-CENT 1023200600039 2.0 3.7 0.422 0.009 1.7 0.6 1023200600040 0.3 0.5 0.4 1023200600041 3.0 2.5 0.436 0.008 1.4 0.2 1023200600042 0.1 0.7 0.2 1023200600043 ENDDATA 8 0 1023200600044 ENDSUBENT 43 0 1023200699999 ENDENTRY 6 0 1023299999999