ENTRY 14297 20240710 150914297000 1 SUBENT 14297001 20240710 150914297001 1 BIB 9 36 14297001 2 TITLE Numbers of Prompt Neutrons per Fission for U233, U235, 14297001 3 Pu239 and Cf252 14297001 4 AUTHOR (B.C.Diven,J.C.Hopkins) 14297001 5 REFERENCE (C,61VIENNA,1,149,1961) 14297001 6 INSTITUTE (1USALAS) 14297001 7 FACILITY (VDG,1USALAS) 14297001 8 DETECTOR (SCIN,FISCH) Large cadmium-loaded liquid scintillator 14297001 9 and fission counter. 14297001 10 METHOD (REC,COINC) In order to deduced the mean number of 14297001 11 neutrons per fission from the observed number of 14297001 12 pulses per gate, it is necessary to know the 14297001 13 efficiency of the detector for fission neutrons. The 14297001 14 efficiency is determined in two ways. The first is to 14297001 15 assume the accurately known value of nubar for 235U 14297001 16 at thermal energy. The detector efficiency is the 14297001 17 mean number of neutrons detected per gate divided by 14297001 18 the known value of nubar. Another method is to 14297001 19 replace the fission detector with proton recoil 14297001 20 neutron detector such as hydrogen-filled proportional 14297001 21 counter that is inserted into the center of liquid 14297001 22 scintillator in place of the fission counter. Then 14297001 23 monoenergetic neutrons are passed through the 14297001 24 proportional counter, and the gate opened with pulses 14297001 25 produced by recoil protons. Every proportional 14297001 26 counter pulse is associated with the scattering of a 14297001 27 neutron out of the beam and into a liquid 14297001 28 scintillator by a hydrogen nucleus in the counter. 14297001 29 For fission spectrum, about 98.5% of the neutrons are 14297001 30 captured in the detector. 14297001 31 ERR-ANALYS (DATA-ERR) The standard deviations reflect 14297001 32 statistical uncertainty due to the number of fission 14297001 33 events observed and to 14297001 34 (ERR-1) the uncertainty in the nubar of 235U. 14297001 35 HISTORY (20170807C) BP 14297001 36 (20230710A) BP: Updated subentry 8. 14297001 37 (20240314U) On. Minor alteration in 008. 14297001 38 ENDBIB 36 0 14297001 39 COMMON 1 3 14297001 40 ERR-1 14297001 41 PER-CENT 14297001 42 1.2 14297001 43 ENDCOMMON 3 0 14297001 44 ENDSUBENT 43 0 1429700199999 SUBENT 14297002 20170807 143014297 2 1 BIB 3 7 14297 2 2 REACTION 1(98-CF-252(0,F),PR,NU) 14297 2 3 2(98-CF-252(0,F),,NU) 14297 2 4 ANALYSIS Determination of absolute nubar for spontaneous 14297 2 5 fission of 252Cf. 14297 2 6 STATUS (TABLE) Table I, page 153. 14297 2 7 (COREL,14297003) Data normalized to 14297 2 8 235U(nth,f) nu-bar=2.430. 14297 2 9 ENDBIB 7 0 14297 2 10 NOCOMMON 0 0 14297 2 11 DATA 3 1 14297 2 12 DATA 1DATA 2DATA-ERR 2 14297 2 13 PRT/FIS PRT/FIS PER-CENT 14297 2 14 3.722 3.731 3.0 14297 2 15 ENDDATA 3 0 14297 2 16 ENDSUBENT 15 0 14297 299999 SUBENT 14297003 20170807 143014297 3 1 BIB 5 10 14297 3 2 REACTION 1(98-CF-252(0,F),PR,NU) 14297 3 3 2(98-CF-252(0,F),DL,NU) 14297 3 4 3(98-CF-252(0,F),,NU) 14297 3 5 ANALYSIS Determination of absolute nubar for spontaneous 14297 3 6 fission of 252Cf normalized to "U.S. value" for nubar 14297 3 7 of 235U. 14297 3 8 MONITOR (92-U-235(N,F),,NU) 14297 3 9 MONIT-REF ((MONIT),D.J.Hughes+,P,BNL-325,1960) 14297 3 10 STATUS (TABLE) Table I, page 153. 14297 3 11 (COREL,14297002) Absolute measurement 14297 3 12 ENDBIB 10 0 14297 3 13 COMMON 3 3 14297 3 14 EN-NRM MONIT MONIT-ERR 14297 3 15 EV PRT/FIS PER-CENT 14297 3 16 0.023 2.430 1.2 14297 3 17 ENDCOMMON 3 0 14297 3 18 DATA 5 1 14297 3 19 DATA 1DATA-ERR 1DATA 2DATA 3DATA-ERR 3 14297 3 20 PRT/FIS PRT/FIS PRT/FIS PRT/FIS PRT/FIS 14297 3 21 3.739 0.051 0.009 3.748 0.051 14297 3 22 ENDDATA 3 0 14297 3 23 ENDSUBENT 22 0 14297 399999 SUBENT 14297004 20170807 143014297 4 1 BIB 4 8 14297 4 2 REACTION 1(92-U-233(N,F),PR,NU) 14297 4 3 2(92-U-233(N,F),DL,NU) 14297 4 4 3(92-U-233(N,F),,NU) 14297 4 5 COMMENT The measurement of nubar for neutron-induced fission 14297 4 6 of 233U, 235U and 239Pu relative to the nubar for the 14297 4 7 spontaneous fission of 252Cf. 14297 4 8 MONITOR (98-CF-252(0,F),,NU) 14297 4 9 STATUS (TABLE) Table I, page 153. 14297 4 10 ENDBIB 8 0 14297 4 11 COMMON 2 3 14297 4 12 EN MONIT 14297 4 13 EV PRT/FIS 14297 4 14 0.0253 3.73 14297 4 15 ENDCOMMON 3 0 14297 4 16 DATA 5 1 14297 4 17 DATA 1DATA-ERR 1DATA 2DATA 3DATA-ERR 3 14297 4 18 PRT/FIS PRT/FIS PRT/FIS PRT/FIS PRT/FIS 14297 4 19 2.440 0.041 0.007 2.447 0.041 14297 4 20 ENDDATA 3 0 14297 4 21 ENDSUBENT 20 0 14297 499999 SUBENT 14297005 20170807 143014297 5 1 BIB 5 9 14297 5 2 REACTION 1(92-U-233(N,F),PR,NU) 14297 5 3 2(92-U-233(N,F),,NU) 14297 5 4 INC-SOURCE (D-D) For neutron energies between 3.5-5 Mev the 14297 5 5 D(d,n) reaction is used. 14297 5 6 COMMENT The measurement of nubar for neutron-induced fission 14297 5 7 of 233U, 235U and 239Pu relative to the nubar for the 14297 5 8 spontaneous fission of 252Cf. 14297 5 9 MONITOR (98-CF-252(0,F),,NU) 14297 5 10 STATUS (TABLE) Table I, page 153. 14297 5 11 ENDBIB 9 0 14297 5 12 COMMON 2 3 14297 5 13 EN MONIT 14297 5 14 MEV PRT/FIS 14297 5 15 4.0 3.73 14297 5 16 ENDCOMMON 3 0 14297 5 17 DATA 4 1 14297 5 18 DATA 1DATA-ERR 1DATA 2DATA-ERR 2 14297 5 19 PRT/FIS PRT/FIS PRT/FIS PRT/FIS 14297 5 20 2.943 0.040 2.950 0.063 14297 5 21 ENDDATA 3 0 14297 5 22 ENDSUBENT 21 0 14297 599999 SUBENT 14297006 20170807 143014297 6 1 BIB 4 7 14297 6 2 REACTION 1(92-U-235(N,F),PR,NU) 14297 6 3 2(92-U-235(N,F),DL,NU) 14297 6 4 COMMENT The measurement of nubar for neutron-induced fission 14297 6 5 of 233U, 235U and 239Pu relative to the nubar for the 14297 6 6 spontaneous fission of 252Cf. 14297 6 7 MONITOR (98-CF-252(0,F),,NU) 14297 6 8 STATUS (TABLE) Table I, page 153. 14297 6 9 ENDBIB 7 0 14297 6 10 COMMON 2 3 14297 6 11 EN MONIT 14297 6 12 EV PRT/FIS 14297 6 13 0.0253 3.73 14297 6 14 ENDCOMMON 3 0 14297 6 15 DATA 3 1 14297 6 16 DATA 1DATA-ERR 1DATA 2 14297 6 17 PRT/FIS PRT/FIS PRT/FIS 14297 6 18 2.414 0.030 0.016 14297 6 19 ENDDATA 3 0 14297 6 20 ENDSUBENT 19 0 14297 699999 SUBENT 14297007 20170807 143014297 7 1 BIB 5 9 14297 7 2 REACTION 1(92-U-235(N,F),PR,NU) 14297 7 3 2(92-U-235(N,F),,NU) 14297 7 4 INC-SOURCE (D-D) For neutron energies between 3.5-5 Mev the 14297 7 5 D(d,n) reaction is used. 14297 7 6 COMMENT The measurement of nubar for neutron-induced fission 14297 7 7 of 233U, 235U and 239Pu relative to the nubar for the 14297 7 8 spontaneous fission of 252Cf. 14297 7 9 MONITOR (98-CF-252(0,F),,NU) 14297 7 10 STATUS (TABLE) Table I, page 153. 14297 7 11 ENDBIB 9 0 14297 7 12 COMMON 2 3 14297 7 13 EN MONIT 14297 7 14 MEV PRT/FIS 14297 7 15 4.0 3.73 14297 7 16 ENDCOMMON 3 0 14297 7 17 DATA 4 1 14297 7 18 DATA 1DATA-ERR 1DATA 2DATA-ERR 2 14297 7 19 PRT/FIS PRT/FIS PRT/FIS PRT/FIS 14297 7 20 2.903 0.048 2.919 0.048 14297 7 21 ENDDATA 3 0 14297 7 22 ENDSUBENT 21 0 14297 799999 SUBENT 14297008 20230710 150914297008 1 BIB 5 17 14297008 2 REACTION 1(94-PU-240(0,F),PR,NU) 14297008 3 2(94-PU-240(0,F),DL,NU) 14297008 4 3(94-PU-240(0,F),,NU) 14297008 5 MONITOR (98-CF-252(0,F),,NU) 14297008 6 COMMENT The measurement of nubar for neutron-induced fission 14297008 7 of 233U, 235U and 239Pu relative to the nubar for the 14297008 8 spontaneous fission of 252Cf. Between -6.28 MeV and 14297008 9 thermal energy, zero threshold reaction. This 14297008 10 interpretation was questioned by the CF-252 14297008 11 evaluators (Denise Neudecker). Additional comment 14297008 12 from Naohiko: "...the authors provide the Pu240 with 14297008 13 En=-6.28 MeV rather than En='Spont.' in Table I. 14297008 14 (What is -6.28 MeV? Neutron separation energy of 14297008 15 240Pu, which is currently known to be ~6.53 MeV.) ." 14297008 16 HISTORY (20230710A) BP: Correctted data set from (N,F) to 14297008 17 spontaneous fission per CF-252 evaluation project. 14297008 18 STATUS (TABLE) Table I, page 153. 14297008 19 ENDBIB 17 0 14297008 20 COMMON 1 3 14297008 21 MONIT 14297008 22 PRT/FIS 14297008 23 3.73 14297008 24 ENDCOMMON 3 0 14297008 25 DATA 5 1 14297008 26 DATA 1DATA-ERR 1DATA 2DATA 3DATA-ERR 3 14297008 27 PRT/FIS PRT/FIS PRT/FIS PRT/FIS PRT/FIS 14297008 28 2.167 0.036 0.009 2.176 0.036 14297008 29 ENDDATA 3 0 14297008 30 ENDSUBENT 29 0 1429700899999 SUBENT 14297009 20170807 143014297 9 1 BIB 4 8 14297 9 2 REACTION 1(94-PU-239(N,F),PR,NU) 14297 9 3 2(94-PU-239(N,F),DL,NU) 14297 9 4 3(94-PU-239(N,F),,NU) 14297 9 5 COMMENT The measurement of nubar for neutron-induced fission 14297 9 6 of 233U, 235U and 239Pu relative to the nubar for the 14297 9 7 spontaneous fission of 252Cf. 14297 9 8 MONITOR (98-CF-252(0,F),,NU) 14297 9 9 STATUS (TABLE) Table I, page 153. 14297 9 10 ENDBIB 8 0 14297 9 11 COMMON 2 3 14297 9 12 EN MONIT 14297 9 13 EV PRT/FIS 14297 9 14 0.0253 3.73 14297 9 15 ENDCOMMON 3 0 14297 9 16 DATA 5 1 14297 9 17 DATA 1DATA-ERR 1DATA 2DATA 3DATA-ERR 3 14297 9 18 PRT/FIS PRT/FIS PRT/FIS PRT/FIS PRT/FIS 14297 9 19 2.814 0.046 0.006 2.820 0.046 14297 9 20 ENDDATA 3 0 14297 9 21 ENDSUBENT 20 0 14297 999999 SUBENT 14297010 20170807 143014297 10 1 BIB 5 9 14297 10 2 REACTION 1(94-PU-239(N,F),PR,NU) 14297 10 3 2(94-PU-239(N,F),,NU) 14297 10 4 INC-SOURCE (D-D) For neutron energies between 3.5-5 Mev the 14297 10 5 D(d,n) reaction is used. 14297 10 6 COMMENT The measurement of nubar for neutron-induced fission 14297 10 7 of 233U, 235U and 239Pu relative to the nubar for the 14297 10 8 spontaneous fission of 252Cf. 14297 10 9 MONITOR (98-CF-252(0,F),,NU) 14297 10 10 STATUS (TABLE) Table I, page 153. 14297 10 11 ENDBIB 9 0 14297 10 12 COMMON 2 3 14297 10 13 EN MONIT 14297 10 14 MEV PRT/FIS 14297 10 15 4.0 3.73 14297 10 16 ENDCOMMON 3 0 14297 10 17 DATA 4 1 14297 10 18 DATA 1DATA-ERR 1DATA 2DATA-ERR 2 14297 10 19 PRT/FIS PRT/FIS PRT/FIS PRT/FIS 14297 10 20 3.415 0.063 3.421 0.063 14297 10 21 ENDDATA 3 0 14297 10 22 ENDSUBENT 21 0 14297 1099999 ENDENTRY 10 0 1429799999999