ENTRY            10300   20191205                             14631030000000001 
SUBENT        10300001   20191205                             14631030000100001 
BIB                 11         52                                 1030000100002 
TITLE      Prompt neutrons emitted from the spontaneous fission   1030000100003 
           of 257Fm                                               1030000100004 
AUTHOR     (J.P.Balagna,J.A.Farrell,G.P.Ford,A.Hemmendinger,      1030000100005 
           D.C.Hoffman,L.R.Veeser,J.B.Wilhelmy)                   1030000100006 
REFERENCE  (C,73ROCH,2,191,1973) Main reference.                  1030000100007 
           (J,ANS,16,315,1973)                                    1030000100008 
INSTITUTE  (1USALAS)                                              1030000100009 
DETECTOR   (SOLST,STANK) Solid state fission fragment detector.   1030000100010 
           Liquid scintillation tank neutron detector.            1030000100011 
SAMPLE     The 257Fm was produced by successive neutron capture   1030000100012 
           in Cm targets irradiated in the high-flux isotope      1030000100013 
           reactor (HFIR) and processed at the trans uranium      1030000100014 
           processing facility (TRU) at Oak Ridge National        1030000100015 
           Laboratory. The 257Fm was further purified at Los      1030000100016 
           Alamos by standard cation column procedures involving  1030000100017 
           elution with ethanol-HCl and hot                       1030000100018 
           a-hydroxy-isobutyrate to separate the Fm from other    1030000100019 
           actinides. The principle contaminant before            1030000100020 
           separation was ~10**6 dis/min of 253Es. A solution of  1030000100021 
           the purified source was evaporated on a 5*10**-3-in. Pt1030000100022 
            disk.                                                 1030000100023 
METHOD     (COINC) 257Fm source was positioned ~3 mm from a 1-    1030000100024 
           cm-diam. by 30-microm-deep Si surface-barrier          1030000100025 
           detector. A 252Cf source, prepared in a similar        1030000100026 
           manner, was placed in the same position relative to a  1030000100027 
           second surface barrier fission detector. The two       1030000100028 
           sources, back-to-back, and their detectors were        1030000100029 
           placed in a vacuum container in the center of a        1030000100030 
           75-cm-diam. spherical Gd-loaded liquid scintillator    1030000100031 
           tank having a l5-cm-diam. cylindrical hole through     1030000100032 
           the center. The apparatus was placed in a low          1030000100033 
           background room having thick concrete walls.           1030000100034 
           Experimental data were collected for more than five    1030000100035 
           months. During that time 10532 257Fm and 98659 252Cf   1030000100036 
           fission events were detected. The 257Fm fission        1030000100037 
           detection rate varied from 5.5 SF/h at the start of    1030000100038 
           the experiment to 1.8 SF/h at the conclusion. From a   1030000100039 
           least squares fit to the observed decay rate we        1030000100040 
           obtained a value of 99.3 -+ 1.6 d for the half-life    1030000100041 
           of 257Fm, in good agreement with the recently          1030000100042 
           published value of 100.5 +- 0.2 d.                     1030000100043 
ERR-ANALYS (DATA-ERR) No information on sources of uncertainties. 1030000100044 
STATUS     (APRVD) Approved by author.                            1030000100045 
DECAY-DATA (100-FM-257,99.3D,SF)                                  1030000100046 
HISTORY    (19740529C)                                            1030000100047 
           (19760204A) Data updated, reaction corrected           1030000100048 
           (19830118A) Converted to reaction formalism            1030000100049 
           (20011227A) Updated to new date formats, lower case.   1030000100050 
           Units updated.                                         1030000100051 
           (20191205A) BP: Added sample information, Cf, decay,   1030000100052 
           the observed neutron probability distributions and     1030000100053 
           MISC data.                                             1030000100054 
ENDBIB              52          0                                 1030000100055 
NOCOMMON             0          0                                 1030000100056 
ENDSUBENT           55          0                                 1030000199999 
SUBENT        10300002   20191205                             14631030000200001 
BIB                  5          6                                 1030000200002 
REACTION   (100-FM-257(0,F),PR,NU)                                1030000200003 
MONITOR    (98-CF-252(0,F),,NU)                                   1030000200004 
MISC-COL   (MISC) Squared standard deviation of nu.               1030000200005 
STATUS     (TABLE) Table II, page 194 of Physics+Chemistry of     1030000200006 
           Fission Symp., Rochester 1973,vol.2,p.191.             1030000200007 
HISTORY    (20191205A) BP: Added MISC data and status.            1030000200008 
ENDBIB               6          0                                 1030000200009 
NOCOMMON             0          0                                 1030000200010 
DATA                 5          1                                 1030000200011 
DATA       DATA-ERR   MONIT      MONIT-ERR  MISC                  1030000200012 
PRT/FIS    PRT/FIS    PRT/FIS    PRT/FIS    PRT/FIS               1030000200013 
       3.77       0.02      3.735      0.014       2.49           1030000200014 
ENDDATA              3          0                                 1030000200015 
ENDSUBENT           14          0                                 1030000299999 
SUBENT        10300003   20191205                             14631030000300001 
BIB                  4          5                                 1030000300002 
REACTION   (98-CF-252(0,F),PR,NU)                                 1030000300003 
MISC-COL   (MISC) Squared standard deviation of nu.               1030000300004 
STATUS     (TABLE) Tables I-II, page 194 of Physics+Chemistry of  1030000300005 
           Fission Symp., Rochester 1973,vol.2,p.191.             1030000300006 
HISTORY    (20191205C) BP                                         1030000300007 
ENDBIB               5          0                                 1030000300008 
NOCOMMON             0          0                                 1030000300009 
DATA                 3          1                                 1030000300010 
DATA       DATA-ERR   MISC                                        1030000300011 
PRT/FIS    PRT/FIS    PRT/FIS                                     1030000300012 
      3.735      0.014       1.57                                 1030000300013 
ENDDATA              3          0                                 1030000300014 
ENDSUBENT           13          0                                 1030000399999 
SUBENT        10300004   20200113                             14631030000400001 
BIB                  3          4                                 1030000400002 
REACTION   (100-FM-257(0,F),PR/NUM,NU)                            1030000400003 
STATUS     (TABLE) Tables I, page 194 of Physics+Chemistry of     1030000400004 
           Fission Symp., Rochester 1973,vol.2,p.191.             1030000400005 
HISTORY    (20191205C) BP                                         1030000400006 
ENDBIB               4          0                                 1030000400007 
NOCOMMON             0          0                                 1030000400008 
DATA                 3         10                                 1030000400009 
PART-OUT   DATA       DATA-ERR                                    1030000400010 
NO-DIM     NO-DIM     NO-DIM                                      1030000400011 
        0.0      0.070      0.003                                 1030000400012 
        1.0      0.176      0.004                                 1030000400013 
        2.0      0.260      0.005                                 1030000400014 
        3.0      0.261      0.005                                 1030000400015 
        4.0      0.154      0.004                                 1030000400016 
        5.0      0.061      0.003                                 1030000400017 
        6.0      0.015      0.002                                 1030000400018 
        7.0      0.003      0.001                                 1030000400019 
        8.0     0.0001     0.0002                                 1030000400020 
        9.0     0.0001     0.0001                                 1030000400021 
ENDDATA             12          0                                 1030000400022 
ENDSUBENT           21          0                                 1030000499999 
SUBENT        10300005   20200113                             14631030000500001 
BIB                  3          4                                 1030000500002 
REACTION   (98-CF-252(0,F),PR/NUM,NU)                             1030000500003 
STATUS     (TABLE) Tables I, page 194 of Physics+Chemistry of     1030000500004 
           Fission Symp., Rochester 1973,vol.2,p.191.             1030000500005 
HISTORY    (20191205C) BP                                         1030000500006 
ENDBIB               4          0                                 1030000500007 
NOCOMMON             0          0                                 1030000500008 
DATA                 3         10                                 1030000500009 
PART-OUT   DATA       DATA-ERR                                    1030000500010 
NO-DIM     NO-DIM     NO-DIM                                      1030000500011 
        0.0      0.041      0.001                                 1030000500012 
        1.0      0.175      0.001                                 1030000500013 
        2.0      0.308      0.002                                 1030000500014 
        3.0      0.276      0.002                                 1030000500015 
        4.0      0.146      0.001                                 1030000500016 
        5.0      0.045      0.001                                 1030000500017 
        6.0      0.008     0.0004                                 1030000500018 
        7.0      0.001     0.0002                                 1030000500019 
        8.0     0.0001    0.00006                                 1030000500020 
        9.0    0.00001    0.00001                                 1030000500021 
ENDDATA             12          0                                 1030000500022 
ENDSUBENT           21          0                                 1030000599999 
ENDENTRY             5          0                                 1030099999999