ENTRY 14799 20241015 15171479900000001 SUBENT 14799001 20241015 15171479900100001 BIB 15 66 1479900100002 TITLE Energy dependence of prompt fissions neutron 1479900100003 multiplicity in the 239Pu(n,f) reaction 1479900100004 AUTHOR (P.Marini,J.Taieb,D.Neudecker,G.Belier,A.Chatillon, 1479900100005 D.Etasse,B.Laurent,P.Morfouace,B.Morillon,M.Devlin, 1479900100006 J.A.Gomez,R.C.Haight,K.J.Kelly,J.M.O'Donnell) 1479900100007 REFERENCE (J,PL/B,835,137513,2022) 1479900100008 #doi:10.1016/j.physletb.2022.137513 1479900100009 REL-REF (A,12397006,H.E.Bethe+,R,LA-1939,1955) 1479900100010 (A,21696006,I.Johnstone,R,AERE-N/R-1912,1956) 1479900100011 (A,40388007,G.N.Smirenkin+,J,AE,4,188,1958) 1479900100012 (A,21135001,D.S.Mather+,J,NP,66,149,1965) 1479900100013 (A,20052002,H.Conde+,J,JNE,22,53,1968) 1479900100014 (A,30006004,R.L.Walsh+,J,JNE,25,321,1971) 1479900100015 (A,20490003,J.Frehaut+,W,FREHAUT,1980) 1479900100016 INSTITUTE (2FR BRC,2FR BOR,2FR SAC,1USALAS,2FR CAE) 1479900100017 FACILITY (LINAC,1USALAS) The Weapons Nuclear Research facility 1479900100018 of Los Alamos Neutron Science Center at the Los 1479900100019 Alamos National Laboratory. 1479900100020 DETECTOR (FISCH,SCIN) A newly-developed, high-efficiency, 1479900100021 light-weight, fast fission chamber, with an improved 1479900100022 discrimination capability between fission and 1479900100023 alpha-decay events, was coupled to 54 EJ-309 liquid 1479900100024 scintillators from the Chi-Nu array to detect 1479900100025 neutrons emitted in fission events. 1479900100026 SAMPLE A high-purity 239Pu target from the JRC-Geel target 1479900100027 preparation laboratory. The fission chamber housed 1479900100028 47 mg of 239Pu arranged in twenty-two deposits and 1479900100029 eleven readout channels, with an alpha-activity of 1479900100030 about 10 MBq per channel, to be compared to a fission 1479900100031 rate of about 15 events/s. 1479900100032 METHOD (TOF) The neutron beam was produced by spallation and 1479900100033 bombarded 239Pu target after a flight path of about 1479900100034 21.5m. The combined setup and the high recorded 1479900100035 statistics lead to a precise reconstruction of the 1479900100036 PFNS as a function of the incident-neutron energy 1479900100037 Enin, from 0.7 to 700 MeV. The data were obtained 1479900100038 with the double time-of-flight technique and an 1479900100039 innovative setup. It allowed to explicitly account 1479900100040 for experimental systematic bias, which have 1479900100041 hampered the precision and accuracy of existing 1479900100042 experimental results, thus providing more 1479900100043 reliable-than-existing data. Neutron detector 1479900100044 efficiencies were obtained by measuring the PFNS of 1479900100045 the 252Cf spontaneous fission reaction in the same 1479900100046 experimental conditions and with the same analysis 1479900100047 procedure as the 239Pu. For each detector, the 1479900100048 measured 252Cf(sf) PFNS was divided by the evaluated 1479900100049 PFNS standard, normalized to the evaluated ENDF/B- 1479900100050 VIII.0 for 252Cf of (3.759+-0.42%), and used to 1479900100051 evaluate the efficiency of every EJ-309 detector. 1479900100052 Data above 24MeV incident-neutron energy should be 1479900100053 considered as a lower limit as fission neutrons with 1479900100054 energies above 14MeV were not detected. 1479900100055 ERR-ANALYS (DATA-ERR) The absolute statistical and systematic 1479900100056 uncertainties, propagated through the data analysis. 1479900100057 The uncertainty on the 252Cf(sf) nubar, 0.42%, was 1479900100058 not propagated through the data analysis. 1479900100059 CORRECTION Data were corrected for four different experimental 1479900100060 biases: the neutron detection energy range, the 1479900100061 presence of a slower incident neutron background 1479900100062 (wrap-around), the limited detector angular 1479900100063 coverage and the detector dead time. 1479900100064 MONITOR (98-CF-252(0,F),PR,NU) 1479900100065 MONIT-REF ((MONIT),A.D.Carlson+,J,NDS,110,3215,2009) 1479900100066 STATUS (APRVD) Approved by P.Marini on October 30, 2024. 1479900100067 HISTORY (20241015C) BP 1479900100068 ENDBIB 66 0 1479900100069 COMMON 2 3 1479900100070 MONIT MONIT-ERR 1479900100071 PER-CENT PER-CENT 1479900100072 3.759 0.42 1479900100073 ENDCOMMON 3 0 1479900100074 ENDSUBENT 73 0 1479900199999 SUBENT 14799002 20241015 15171479900200001 BIB 2 3 1479900200002 REACTION (94-PU-239(N,F),PR,NU) 1479900200003 STATUS (TABLE,,P.Marini+,J,PL/B,835,137513,2022). 1479900200004 Data were provided by P.Marini on October 29, 2024. 1479900200005 ENDBIB 3 0 1479900200006 NOCOMMON 0 0 1479900200007 DATA 4 83 1479900200008 EN EN-ERR DATA DATA-ERR 1479900200009 MEV MEV PRT/FIS PRT/FIS 1479900200010 0.97 0.01 3.023 0.004 1479900200011 1.44 0.02 3.091 0.005 1479900200012 1.94 0.02 3.166 0.005 1479900200013 2.44 0.03 3.245 0.007 1479900200014 2.94 0.03 3.313 0.007 1479900200015 3.44 0.02 3.375 0.009 1479900200016 3.95 0.03 3.441 0.009 1479900200017 4.45 0.06 3.517 0.011 1479900200018 4.94 0.06 3.578 0.012 1479900200019 5.44 0.02 3.673 0.014 1479900200020 5.95 0.07 3.761 0.016 1479900200021 6.60 0.03 3.852 0.013 1479900200022 7.39 0.07 3.948 0.014 1479900200023 8.19 0.03 4.084 0.017 1479900200024 8.99 0.03 4.177 0.019 1479900200025 9.88 0.10 4.332 0.021 1479900200026 10.88 0.02 4.536 0.029 1479900200027 11.89 0.05 4.639 0.032 1479900200028 12.89 0.13 4.753 0.037 1479900200029 13.89 0.08 4.900 0.040 1479900200030 14.89 0.02 5.040 0.050 1479900200031 15.89 0.04 5.190 0.050 1479900200032 16.89 0.11 5.360 0.060 1479900200033 17.89 0.16 5.300 0.050 1479900200034 18.89 0.09 5.520 0.070 1479900200035 19.90 0.03 5.670 0.070 1479900200036 21.10 0.10 5.700 0.060 1479900200037 22.60 0.20 5.740 0.060 1479900200038 24.10 0.20 6.030 0.060 1479900200039 25.60 0.05 6.030 0.060 1479900200040 27.90 0.30 6.240 0.050 1479900200041 30.90 0.10 6.460 0.050 1479900200042 33.90 0.10 6.640 0.050 1479900200043 37.90 0.30 6.920 0.050 1479900200044 42.90 0.10 7.160 0.050 1479900200045 47.90 0.20 7.380 0.050 1479900200046 52.90 0.50 7.600 0.050 1479900200047 57.90 0.10 7.740 0.050 1479900200048 62.90 0.50 7.860 0.050 1479900200049 67.90 0.00 8.100 0.060 1479900200050 72.90 0.60 8.400 0.070 1479900200051 77.90 0.30 8.400 0.060 1479900200052 82.90 0.10 8.500 0.060 1479900200053 90.30 0.70 8.700 0.050 1479900200054 100.30 0.00 8.910 0.050 1479900200055 110.30 0.70 9.190 0.060 1479900200056 120.30 0.40 9.340 0.060 1479900200057 130.30 0.10 9.530 0.060 1479900200058 140.30 0.80 9.680 0.060 1479900200059 150.30 0.70 9.710 0.060 1479900200060 160.30 0.40 9.920 0.070 1479900200061 170.40 0.10 10.070 0.070 1479900200062 180.40 0.30 10.170 0.070 1479900200063 190.40 0.90 10.290 0.070 1479900200064 200.40 0.80 10.480 0.070 1479900200065 210.40 0.60 10.650 0.070 1479900200066 220.40 0.50 10.700 0.080 1479900200067 230.40 0.20 10.760 0.070 1479900200068 240.36 0.02 10.910 0.080 1479900200069 250.40 0.20 11.080 0.080 1479900200070 265.30 0.60 11.300 0.060 1479900200071 285.30 1.20 11.400 0.060 1479900200072 305.30 1.00 11.740 0.060 1479900200073 325.30 0.80 11.920 0.060 1479900200074 345.30 0.60 12.270 0.070 1479900200075 365.30 0.40 12.430 0.070 1479900200076 385.30 0.10 12.670 0.070 1479900200077 405.30 0.20 12.790 0.070 1479900200078 425.30 0.60 12.810 0.070 1479900200079 445.30 0.90 13.140 0.080 1479900200080 465.40 1.50 13.190 0.070 1479900200081 485.40 1.50 13.430 0.070 1479900200082 505.30 1.50 13.480 0.070 1479900200083 525.50 1.50 13.610 0.060 1479900200084 545.40 1.40 13.930 0.070 1479900200085 565.40 1.40 14.010 0.070 1479900200086 585.40 1.40 14.120 0.060 1479900200087 605.30 1.30 14.330 0.070 1479900200088 625.20 1.30 14.410 0.070 1479900200089 645.10 1.20 14.570 0.080 1479900200090 665.00 1.10 14.660 0.100 1479900200091 685.00 1.10 14.630 0.110 1479900200092 704.80 1.00 14.680 0.140 1479900200093 ENDDATA 85 0 1479900200094 ENDSUBENT 93 0 1479900299999 ENDENTRY 2 0 1479999999999