ENTRY 30913 20100917 31463091300000001 SUBENT 30913001 20100917 31463091300100001 BIB 10 29 3091300100002 TITLE Fine structure in the neutron emission nu(A) from 3091300100003 252Cf spontaneous fission fragments 3091300100004 AUTHOR (R.L.Walsh,J.W.Boldeman) 3091300100005 INSTITUTE (3AULAUA) 3091300100006 REFERENCE (J,NP/A,276,189,1977) 3091300100007 METHOD the double-energy method and low energy neutron 3091300100008 detection geometry 3091300100009 SAMPLE The 252Cf spontaneous fission source was deposited on 3091300100010 a 110 mu-g/cm2 nickel backing foil. The source 3091300100011 activity was 1.2 x 10**3 fission/s for the first 3091300100012 series of measurements (6 x 10**5 two-fragment 3091300100013 coincidence events analyzed and 5 x l0**2 fission/s 3091300100014 for the second series (1.2 x 10**6 coincidences 3091300100015 analyzed. 3091300100016 DETECTOR (SIBAR) The two fission fragment surface barrier 3091300100017 detectors were used in the first series of 3091300100018 measurements collimated to 1 cm2 active area. For the 3091300100019 second series ORTEC surface barrier detectors were 3091300100020 used, collimated to 3 cm2 active area. 3091300100021 (STANK) The scintillator tank was operated with a 4-Pi 3091300100022 neutron detection efficiency of ~ 45%, giving 3091300100023 typical count rates of 0.2 genuine fission neutron 3091300100024 per gate and 0.15 background counts per gate. 3091300100025 CORRECTION Following corrections were made for the scintillator 3091300100026 tank geometry and efficiency. 3091300100027 The data were not corrected for dead time losses, as 3091300100028 this correction was negligible. 3091300100029 STATUS (TABLE) data from tbl.1 of Nucl.Phys. A276,189,1977 3091300100030 HISTORY (20100917C) SD 3091300100031 ENDBIB 29 0 3091300100032 NOCOMMON 0 0 3091300100033 ENDSUBENT 32 0 3091300199999 SUBENT 30913002 20100920 31463091300200001 BIB 2 4 3091300200002 REACTION (98-CF-252(0,F),PRE,AKE,LF+HF) 3091300200003 The average pre-neutron emission total kinetic 3091300200004 energy of the fragments 3091300200005 STATUS (TABLE) data from p.192 of Nucl.Phys. A276 3091300200006 ENDBIB 4 0 3091300200007 NOCOMMON 0 0 3091300200008 DATA 2 1 3091300200009 DATA DATA-ERR 3091300200010 MEV MEV 3091300200011 185.7 1.5 3091300200012 ENDDATA 3 0 3091300200013 ENDSUBENT 12 0 3091300299999 SUBENT 30913003 20100917 31463091300300001 BIB 2 8 3091300300002 REACTION (98-CF-252(0,F)MASS,,NU) 3091300300003 Number of neutron emitted as a function of 3091300300004 fragment mass 3091300300005 The final nu(A) results are a weighted sum 3091300300006 of the two series (1.8 xl0**6 total events). The 3091300300007 nu(A) behaviour observed in each series, however, 3091300300008 was very similar. 3091300300009 ERR-ANALYS (DATA-ERR) Total uncertainty 3091300300010 ENDBIB 8 0 3091300300011 NOCOMMON 0 0 3091300300012 DATA 3 41 3091300300013 MASS DATA DATA-ERR 3091300300014 NO-DIM PRT/FIS PRT/FIS 3091300300015 88.0 0.79 0.04 3091300300016 90.0 1.24 0.04 3091300300017 92.0 1.33 0.03 3091300300018 94.0 1.21 0.03 3091300300019 96.0 1.29 0.02 3091300300020 98.0 1.30 0.02 3091300300021 100.0 1.29 0.02 3091300300022 102.0 1.32 0.01 3091300300023 104.0 1.41 0.01 3091300300024 106.0 1.52 0.01 3091300300025 108.0 1.81 0.01 3091300300026 110.0 1.99 0.01 3091300300027 112.0 2.24 0.02 3091300300028 114.0 2.45 0.02 3091300300029 116.0 2.77 0.02 3091300300030 118.0 3.06 0.03 3091300300031 120.0 3.38 0.04 3091300300032 122.0 3.67 0.06 3091300300033 124.0 3.89 0.07 3091300300034 126.0 2.39 0.05 3091300300035 126.0 2.39 0.05 3091300300036 128.0 0.71 0.02 3091300300037 130.0 0.36 0.01 3091300300038 132.0 0.61 0.01 3091300300039 134.0 0.89 0.01 3091300300040 136.0 1.12 0.01 3091300300041 138.0 1.27 0.01 3091300300042 140.0 1.49 0.01 3091300300043 142.0 1.61 0.01 3091300300044 144.0 1.73 0.01 3091300300045 146.0 1.94 0.02 3091300300046 148.0 2.10 0.02 3091300300047 150.0 2.18 0.02 3091300300048 152.0 2.46 0.03 3091300300049 154.0 2.51 0.03 3091300300050 156.0 2.86 0.04 3091300300051 158.0 2.76 0.05 3091300300052 160.0 3.07 0.07 3091300300053 162.0 2.91 0.08 3091300300054 164.0 3.47 0.12 3091300300055 166.0 3.48 0.15 3091300300056 ENDDATA 43 0 3091300300057 ENDSUBENT 56 0 3091300399999 ENDENTRY 3 0 3091399999999