ENTRY 21453 20120917 22342145300000001 SUBENT 21453001 20120917 22342145300100001 BIB 10 32 2145300100002 INSTITUTE (2FR SAC) 2145300100003 REFERENCE (J,JPR,21,617,196009) In French 2145300100004 (C,58GENEVA,16,106,195809) superseded. 2145300100005 (J,CR,247,200,195802) 2145300100006 (J,JPR,19,66,195801) 2145300100007 AUTHOR (J.Leroy) 2145300100008 TITLE Mean number of prompt neutrons emitted in the fission 2145300100009 of U-238, Pu-239, Th-232 2145300100010 METHOD (COINC) Fission fragments detected in coincidence 2145300100011 with prompt fission neutrons. 2145300100012 The quantity detector-efficiency*nu-bar was measured 2145300100013 in all the experiments. by comparison of this quantity2145300100014 with its value obtained with the same apparatus for a 2145300100015 reference nucleus, the nu-bar can be determined, 2145300100016 from the nu-bar value of the reference nucleus, if 2145300100017 one assumes that the efficiency remains the same. 2145300100018 DETECTOR (COIN,FISCH,BF3) A number of BF3 counters surrounding 2145300100019 the fission chamber in coincidence. 2145300100020 PART-DET (FF) Fission fragments, and 2145300100021 (N) prompt fission neutrons. 2145300100022 STATUS (TABLE) Data from the text of J.de Phys.,21,617. 2145300100023 CORRECTION .For background from diffused neutrons, random coinci- 2145300100024 dences, non detected fission events. Correction 2145300100025 for neutron number loss due to simultaneous detection 2145300100026 of 2 or more neutrons negligible. Other corrections 2145300100027 applied described in subworks. 2145300100028 HISTORY (19800305T) G.C. 2145300100029 (19800318E) 2145300100030 (20120917A) SD: Updated to new date formats,lower case.2145300100031 Corrected according last EXFOR rules and Dict. 2145300100032 INC-SOURCE was moved to Subents 2-5. 2145300100033 Units in Subents 2-5 were changed. 2145300100034 ENDBIB 32 0 2145300100035 NOCOMMON 0 0 2145300100036 ENDSUBENT 35 0 2145300199999 SUBENT 21453002 20120917 22342145300200001 BIB 8 31 2145300200002 REACTION (92-U-238(N,F),PR,NU) 2145300200003 FACILITY (CCW,2FR SAC) Cockcroft Walton accelerator, operated 2145300200004 at 220 keV to produce 14.2 MeV neutrons. 2145300200005 (REAC,2FR SAC) Reactor Pile EL.2. This beam also gave 2145300200006 the neutrons for the creation of the fission neutron 2145300200007 spectrum, and also the Maxwellian neutron spectrum. 2145300200008 SAMPLE .500 mg natural uranium in 40 deposits of 1.8 mg/cm2, 2145300200009 produced by painting of uranyl nitrate onto 2145300200010 the two sides of an Al foil of 0.03 mm thickness. 2145300200011 There is also a measurement done with a sample 2145300200012 made poorer in U-235 (2.E-4 U235) in order to show 2145300200013 that at 14.2 MeV the fissions come only from U-238 2145300200014 in both of the samples. 2145300200015 MONITOR (92-U-235(N,F),PR,NU) 2145300200016 INC-SOURCE (D-T) Deuteron-tritium reaction in tritium-titanium 2145300200017 target for the production of 14.2 MeV neutrons. 2145300200018 CORRECTION .Difference in efficiency between the monitor 2145300200019 measurement and the main measurement (smaller than 1%)2145300200020 fission fragment anisotropy effects resulting 2145300200021 in a 2.5 +- 2% lowering of the efficiency, and 2145300200022 incoming neutron spectrum degradation due to 2145300200023 inelastic scattering of the neutrons with the 2145300200024 collimator walls (+0.15+-0.01 correction) 2145300200025 ERR-ANALYS (DATA-ERR) .Uncertainty includes statistics and 2145300200026 uncertainties of the random coincidences determination2145300200027 caused by neutron flux fluctuations and coincidence 2145300200028 time fluctuations. The value given is a weighted mean 2145300200029 of the results of the two independent measurements 2145300200030 described above. 2145300200031 HISTORY (20120917A) SD: DATA units were changed 2145300200032 (NO-DIM -> PRT/FIS). 2145300200033 ENDBIB 31 0 2145300200034 NOCOMMON 0 0 2145300200035 DATA 6 1 2145300200036 EN EN-NRM MONIT MONIT-ERR DATA DATA-ERR 2145300200037 MEV EV PRT/FIS PRT/FIS PRT/FIS PRT/FIS 2145300200038 14.2 0.025 2.47 0.03 4.55 0.152145300200039 ENDDATA 3 0 2145300200040 ENDSUBENT 39 0 2145300299999 SUBENT 21453003 20120917 22342145300300001 BIB 9 21 2145300300002 REACTION (90-TH-232(N,F),PR,NU) 2145300300003 SAMPLE .500 mg U-238 in 40 deposits of 3 cm diameter, made 2145300300004 by painting of uranyl nitrate on both sides of an 2145300300005 aluminium foil of 0.03 mm thickness, and 500 mg Th-2322145300300006 in 40 deposits of 3 cm diam, made by cathodic 2145300300007 pulverisation on similar Al-foils. 2145300300008 MONITOR (92-U-238(N,F),PR,NU) 2145300300009 FACILITY (CCW,2FR SAC) Cockcroft Walton accelerator, operated 2145300300010 at 220 keV to produce 14.2 MeV neutrons. 2145300300011 INC-SOURCE (D-T) Deuteron-tritium reaction in tritium-titanium 2145300300012 target for the production of 14.2 MeV neutrons. 2145300300013 CORRECTION .For degradation of the incoming neutron spectrum 2145300300014 due to inelastic scattering of the neutrons with 2145300300015 the collimator walls. 2145300300016 ERR-ANALYS (DATA-ERR) .No complete analysis given. 2145300300017 (ERR-1) 2% error from the anisotropy of the fission 2145300300018 fragments which is different in the monitor - 2145300300019 measurement and in the main measurement. 2145300300020 STATUS (DEP,21453002) Value from Subent 2 used for normaliz. 2145300300021 HISTORY (20120917A) SD: DATA units were changed 2145300300022 (NO-DIM -> PRT/FIS). 2145300300023 ENDBIB 21 0 2145300300024 NOCOMMON 0 0 2145300300025 DATA 6 1 2145300300026 EN MONIT MONIT-ERR DATA DATA-ERR ERR-1 2145300300027 MEV PRT/FIS PRT/FIS PRT/FIS PRT/FIS PER-CENT 2145300300028 14.2 4.55 0.15 4.64 0.21 2.2145300300029 ENDDATA 3 0 2145300300030 ENDSUBENT 29 0 2145300399999 SUBENT 21453004 20120917 22342145300400001 BIB 9 22 2145300400002 REACTION (94-PU-239(N,F),PR,NU) 2145300400003 FACILITY (CCW,2FR SAC) Cockcroft Walton accelerator, operated 2145300400004 at 220 keV to produce 14.2 MeV neutrons. 2145300400005 SAMPLE .500 mg natural uranium in 40 deposits, made by 2145300400006 painting of uranyl nitrate on both sides of Al 2145300400007 foils of 0.03 mm thickness. 80 mg Pu in 4 2145300400008 independent cells of the fission chamber. 2145300400009 METHOD .In order to discriminate against the spontaneous 2145300400010 fission activity of Pu-240, and against thermal 2145300400011 neutron induced fissions (neutrons slowed down in 2145300400012 the paraffin surrounding the chamber), the 2145300400013 experiments were done in coincidence with the 2145300400014 associated alpha particles from the neutron 2145300400015 production d-t-reaction. These alphas were detected 2145300400016 with a Zn-S-(Ag) scintillator. 2145300400017 MONITOR (92-U-238(N,F),PR,NU) 2145300400018 INC-SOURCE (D-T) Deuteron-tritium reaction in tritium-titanium 2145300400019 target for the production of 14.2 MeV neutrons. 2145300400020 ERR-ANALYS (DATA-ERR) .Error is mainly statistical. 2145300400021 STATUS (DEP,21453002) Value from Subent 2 used for normaliz. 2145300400022 HISTORY (20120917A) SD: DATA units were changed 2145300400023 (NO-DIM -> PRT/FIS). 2145300400024 ENDBIB 22 0 2145300400025 NOCOMMON 0 0 2145300400026 DATA 5 1 2145300400027 EN MONIT MONIT-ERR DATA DATA-ERR 2145300400028 MEV PRT/FIS PRT/FIS PRT/FIS PRT/FIS 2145300400029 14.2 4.55 0.15 4.75 0.4 2145300400030 ENDDATA 3 0 2145300400031 ENDSUBENT 30 0 2145300499999 SUBENT 21453005 20120917 22342145300500001 BIB 8 15 2145300500002 REACTION (92-U-238(N,F),PR,NU,,FIS) 2145300500003 SAMPLE .700 mg natural U in the form of oxide. 2145300500004 FACILITY (REAC,2FR SAC) Reactor Pile EL.2. This beam also gave 2145300500005 the neutrons for the creation of the fission neutron 2145300500006 spectrum, and also the Maxwellian neutron spectrum. 2145300500007 MONITOR (92-U-235(N,F),PR,NU,,MXW) 2145300500008 INC-SOURCE .U-235(n,f)-reaction for the creation of the fission 2145300500009 neutron spectrum. A 3 mm thick layer of 20% 2145300500010 enrichment was used. 2145300500011 CORRECTION .For fission fragment anisotropy and for spontaneous 2145300500012 fission of U-238. 2145300500013 ERR-ANALYS (DATA-ERR) .Main contribution to total error 2145300500014 is statistical. 2145300500015 HISTORY (20120917A) SD: DATA units were changed 2145300500016 (NO-DIM -> PRT/FIS). EN-DUMMY -> EN-MEAN 2145300500017 ENDBIB 15 0 2145300500018 NOCOMMON 0 0 2145300500019 DATA 6 1 2145300500020 EN-MEAN EN-NRM MONIT MONIT-ERR DATA DATA-ERR 2145300500021 MEV EV PRT/FIS PRT/FIS PRT/FIS PRT/FIS 2145300500022 3.1 0.025 2.47 0.03 2.93 0.0752145300500023 ENDDATA 3 0 2145300500024 ENDSUBENT 23 0 2145300599999 SUBENT 21453006 20120917 22342145300600001 BIB 7 11 2145300600002 REACTION (92-U-238(0,F),PR,NU) 2145300600003 SAMPLE .700 mg natural uranium in form of oxide. 2145300600004 FACILITY (REAC,2FR SAC) Reactor Pile EL.2. This beam also gave 2145300600005 the neutrons for the creation of the fission neutron 2145300600006 spectrum, and also the Maxwellian neutron spectrum. 2145300600007 MONITOR (92-U-235(N,F),PR,NU,,MXW) 2145300600008 CORRECTION .For alpha pile up, thermal neutron induced fission, 2145300600009 random coincidences all negligible and in total less 2145300600010 than 1%. No anisotropy correction necessary. 2145300600011 ERR-ANALYS (DATA-ERR) .No details given. 2145300600012 HISTORY (20120917S) SD: Data were restored. 2145300600013 ENDBIB 11 0 2145300600014 NOCOMMON 0 0 2145300600015 DATA 5 1 2145300600016 EN-NRM MONIT MONIT-ERR DATA DATA-ERR 2145300600017 EV PRT/FIS PRT/FIS PRT/FIS PRT/FIS 2145300600018 0.025 2.47 0.03 2.10 0.08 2145300600019 ENDDATA 3 0 2145300600020 ENDSUBENT 19 0 2145300699999 ENDENTRY 6 0 2145399999999