ENTRY 33084 20160523 31753308400000001 SUBENT 33084001 20160523 31753308400100001 BIB 13 47 3308400100002 TITLE Prompt fission neutron spectra in 3308400100003 fast-neutron-induced fission of 238U 3308400100004 AUTHOR (V.V.Desai, B.K.Nayak, A.Saxena, S.V.Suryanarayana, 3308400100005 R.Capote) 3308400100006 INSTITUTE (3INDTRM,3ZZZIAE) 3308400100007 REFERENCE (J,PR/C,92,014609,2015) 3308400100008 (J,NDS,131,1,2016) Tabulated data given 3308400100009 SAMPLE Natural 238U (99.30%) target of thickness 2.1 mg/cm2 3308400100010 and dimension 1.0x1.0 cm2. 3308400100011 METHOD (TOF) Flight path of 70.0 cm between the fission 3308400100012 chamber centre and scintillator. 3308400100013 (COINC) Neutrons and fission fragments detected in 3308400100014 coincidence 3308400100015 (PSD) 3308400100016 FACILITY (VDGT,3INDTRM) 6MV Folded Tandem Ion Accelerator 3308400100017 DETECTOR (FISCH) The produced neutrons are allowed to fall on 3308400100018 a 238U target mounted on the cathode plate of a 3308400100019 fission chamber. 3308400100020 The fission fragments produced in the 238U(n,f) 3308400100021 reaction are detected in 2pi geometry in the fission 3308400100022 chamber. 3308400100023 The cathode plate was kept at ground potential, while 3308400100024 the anode was biased to 600 V through a preamplifier. 3308400100025 The fission fragments ionize the air between the two 3308400100026 plates, generating electron-ion pairs. 3308400100027 The generated electron-ion pairs are then collected at 3308400100028 their respective electrodes, leading to an electrical 3308400100029 pulse, signing a fission event which is then used as 3308400100030 a start pulse for the time-of-flight measurement. 3308400100031 (SCIN) Two EJ301 liquid organic scintillator 3308400100032 detectors (12.7 cm diameter and 5 cm thick) were 3308400100033 placed at a distance of about 70 cm from the fission 3308400100034 chamber, making an angle of 60 degree with respect to 3308400100035 the incident neutron beam direction on either side of 3308400100036 the beam. 3308400100037 The detection efficiency was determined by measuring 3308400100038 the 252Cf neutron spectrum. 3308400100039 PART-DET (FF,N) 3308400100040 INC-SOURCE (P-LI7) Irradiation of natural lithium metallic target 3308400100041 (4.0 mg/cm2 thick, 1.0x1.0 cm2, energy loss in the 3308400100042 half thickness of ~120 keV) by protons at 4.0, 4.5 3308400100043 and 5.0 MeV. 3308400100044 Neutron energy spread due to finite opening angle of 3308400100045 neutron emission (+/-14 deg) is ~100 keV. 3308400100046 MONITOR (98-CF-252(0,F),PR,NU/DE) 3308400100047 MONIT-REF (V0101002,W.Mannhart,S,IAEA-TECDOC-410,158,1987) 3308400100048 HISTORY (20160523C) Compiled by H.Lalremruata+BL 3308400100049 ENDBIB 47 0 3308400100050 NOCOMMON 0 0 3308400100051 ENDSUBENT 50 0 3308400199999 SUBENT 33084002 20160523 31753308400200001 BIB 5 22 3308400200002 REACTION (92-U-238(N,F),PR,NU/DE) 3308400200003 ANALYSIS The neutron energy spectrum is generated for the 3308400200004 coincidence region (prompt neutron zone) of TOF 3308400200005 spectra. 3308400200006 The spectrum is normalized to the number of fission 3308400200007 events and the solid angle of the neutron detector 3308400200008 and corrected with the measured neutron detection 3308400200009 efficiency. 3308400200010 CORRECTION An energy spectrum corresponding to a constant 3308400200011 background of a width similar to the coincidence 3308400200012 region of the TOF is also generated by appropriately 3308400200013 shifting the time scale. 3308400200014 The neutron energy spectra corresponding background 3308400200015 region is subtracted from the coincidence region. 3308400200016 ERR-ANALYS (ERR-T) Total uncertainty 3308400200017 (ERR-S) Statistical uncertainty 3308400200018 (ERR-SYS) The systematic uncertainties in the present 3308400200019 data include uncertainties in: 3308400200020 (ERR-1) detector efficiency measurements (5%), 3308400200021 (ERR-2,,12.) separation of neutron and gamma events 3308400200022 by PSD and in the background subtraction (<12%). 3308400200023 STATUS (TABLE) Table XV of Nuclear Data Sheets 131(2016)1 3308400200024 ENDBIB 22 0 3308400200025 COMMON 1 3 3308400200026 ERR-1 3308400200027 PER-CENT 3308400200028 5. 3308400200029 ENDCOMMON 3 0 3308400200030 DATA 7 37 3308400200031 EN E E-ERR DATA ERR-T ERR-S 3308400200032 ERR-SYS 3308400200033 MEV MEV MEV PT/FIS/MEV PT/FIS/MEV PT/FIS/MEV 3308400200034 PT/FIS/MEV 3308400200035 2.0 0.75 0.053 1.0110 0.0569 0.02903308400200036 0.0490 3308400200037 2.0 1.25 0.089 0.8960 0.0340 0.03003308400200038 0.0160 3308400200039 2.0 1.75 0.125 0.7410 0.0269 0.02503308400200040 0.0100 3308400200041 2.0 2.25 0.160 0.4940 0.0280 0.02703308400200042 0.0074 3308400200043 2.0 2.75 0.196 0.4480 0.0257 0.02503308400200044 0.0058 3308400200045 2.0 3.25 0.232 0.2810 0.0235 0.02303308400200046 0.0049 3308400200047 2.0 3.75 0.267 0.2120 0.0283 0.02803308400200048 0.0041 3308400200049 2.0 4.25 0.303 0.1700 0.0253 0.02503308400200050 0.0036 3308400200051 2.0 4.75 0.339 0.1030 0.0242 0.02403308400200052 0.0031 3308400200053 2.0 5.50 0.392 0.0570 0.0182 0.01803308400200054 0.0026 3308400200055 2.0 6.50 0.464 0.0260 0.0110 0.01103308400200056 0.0023 3308400200057 2.0 7.50 0.535 0.0120 0.0068 0.00643308400200058 0.0022 3308400200059 2.0 8.50 0.606 0.0084 0.0075 0.00723308400200060 0.0019 3308400200061 2.5 0.75 0.053 1.017 0.094 0.02703308400200062 0.09030 3308400200063 2.5 1.25 0.089 0.918 0.047 0.02503308400200064 0.03940 3308400200065 2.5 1.75 0.125 0.711 0.034 0.02403308400200066 0.02480 3308400200067 2.5 2.25 0.160 0.476 0.027 0.01903308400200068 0.01850 3308400200069 2.5 2.75 0.196 0.438 0.023 0.01803308400200070 0.01460 3308400200071 2.5 3.25 0.232 0.273 0.020 0.01403308400200072 0.01460 3308400200073 2.5 3.75 0.267 0.232 0.017 0.01403308400200074 0.01050 3308400200075 2.5 4.25 0.303 0.174 0.015 0.01203308400200076 0.00912 3308400200077 2.5 4.75 0.339 0.116 0.014 0.01203308400200078 0.00807 3308400200079 2.5 5.50 0.392 0.070 0.012 0.01003308400200080 0.00753 3308400200081 2.5 6.50 0.464 0.027 0.012 0.00963308400200082 0.00659 3308400200083 3.0 0.75 0.053 1.1100 0.1218 0.02103308400200084 0.1200 3308400200085 3.0 1.25 0.089 0.8690 0.0470 0.02303308400200086 0.0410 3308400200087 3.0 1.75 0.125 0.7700 0.0320 0.02003308400200088 0.0250 3308400200089 3.0 2.25 0.160 0.6230 0.0269 0.02003308400200090 0.0180 3308400200091 3.0 2.75 0.196 0.4540 0.0220 0.01703308400200092 0.0140 3308400200093 3.0 3.25 0.232 0.3270 0.0208 0.01703308400200094 0.0120 3308400200095 3.0 3.75 0.267 0.2270 0.0172 0.01403308400200096 0.0100 3308400200097 3.0 4.25 0.303 0.1470 0.0175 0.01503308400200098 0.0090 3308400200099 3.0 4.75 0.339 0.1110 0.0143 0.01203308400200100 0.0078 3308400200101 3.0 5.50 0.392 0.0810 0.0119 0.01003308400200102 0.0065 3308400200103 3.0 6.50 0.464 0.0390 0.0126 0.01203308400200104 0.0039 3308400200105 3.0 7.50 0.535 0.0270 0.0083 0.00793308400200106 0.0025 3308400200107 3.0 8.50 0.606 0.0082 0.0052 0.00513308400200108 0.0011 3308400200109 ENDDATA 78 0 3308400200110 ENDSUBENT 109 0 3308400299999 SUBENT 33084003 20160525 31753308400300001 BIB 4 8 3308400300002 REACTION 1(92-U-238(N,F),PR,NU) 3308400300003 2(92-U-238(N,F)0-NN-1,PR,KE) 3308400300004 ANALYSIS Derived through fitting with Watt formula to 3308400300005 extrapolate the measured spectra 3308400300006 ERR-ANALYS (DATA-ERR) No information on the source of uncertianty 3308400300007 STATUS (TABLE) Table XVI of Nuclear Data Sheets 131(2016)1 3308400300008 (COREL,33084004) Data obtained with Maxwellian 3308400300009 distribution 3308400300010 ENDBIB 8 0 3308400300011 NOCOMMON 0 0 3308400300012 DATA 5 3 3308400300013 EN DATA 1DATA-ERR 1DATA 2DATA-ERR 2 3308400300014 MEV PRT/FIS PRT/FIS MEV MEV 3308400300015 2.0 2.590 0.020 2.280 0.017 3308400300016 2.5 2.620 0.020 2.300 0.018 3308400300017 3.0 2.720 0.025 2.310 0.020 3308400300018 ENDDATA 5 0 3308400300019 ENDSUBENT 18 0 3308400399999 SUBENT 33084004 20160525 31753308400400001 BIB 4 8 3308400400002 REACTION 1(92-U-238(N,F),PR,NU) 3308400400003 2(92-U-238(N,F)0-NN-1,PR,KE) 3308400400004 3(92-U-238(N,F)0-NN-1,PR,KEM) 3308400400005 ANALYSIS Derived through fitting with Maxwellian distribution 3308400400006 to extrapolate the measured spectra 3308400400007 ERR-ANALYS (DATA-ERR) No information on the source of uncertianty 3308400400008 STATUS (TABLE) Table XVI of Nuclear Data Sheets 131(2016)1 3308400400009 (COREL,33084003) Data obtained with Watt formula 3308400400010 ENDBIB 8 0 3308400400011 NOCOMMON 0 0 3308400400012 DATA 7 3 3308400400013 EN DATA 1DATA-ERR 1DATA 2DATA-ERR 2DATA 33308400400014 DATA-ERR 3 3308400400015 MEV PRT/FIS PRT/FIS MEV MEV MEV 3308400400016 MEV 3308400400017 2.0 2.590 0.025 1.860 0.015 1.24 3308400400018 0.01 3308400400019 2.5 2.620 0.025 1.900 0.015 1.27 3308400400020 0.01 3308400400021 3.0 2.620 0.025 1.920 0.015 1.29 3308400400022 0.01 3308400400023 ENDDATA 10 0 3308400400024 ENDSUBENT 23 0 3308400499999 ENDENTRY 4 0 3308499999999