ENTRY 21387 20061205 21812138700000001 SUBENT 21387001 20061205 21812138700100001 BIB 15 53 2138700100002 INSTITUTE (2UK ALD) 2138700100003 REFERENCE (J,PR,139,B852,196508) Main reference 2138700100004 AUTHOR (E.E.Maslin,J.A.Moore,J.M.A.Reichelt,J.B.Crowden) 2138700100005 TITLE -Absolute fission cross section of U-235 for 2200 m/Se 2138700100006 neutrons -. 2138700100007 FACILITY (CHOPF) Fast chopper, rotated at 625 rpm. 2138700100008 INC-SOURCE (REAC ) Reactor neutrons. 2138700100009 SAMPLE .Thick foil of U-235, 92.93 pc U-235, 1.17 pc U-234, 2138700100010 0.18 pc U-236, 5.72 pc U-238, 0.028 pc Fe, 0.015 pc 2138700100011 silicon, 0.051 pc carbon. Thickness 131 mg/cm2. 2138700100012 METHOD (TOF ) Time of flight. 2138700100013 DETECTOR (SCIN ) Liquid scintillator, with pulse shape 2138700100014 discrimination against gammas. 2138700100015 ANALYSIS .Quoted data is the weighted mean of many measurements 2138700100016 with different foil thicknesses and geometry for 2138700100017 neutron counters. 2138700100018 MONITOR .Neutron flux monitored with a thick B-10 beam stop 2138700100019 with detection of 478 KeV gammas in calibrated 2138700100020 NaI(Tl) crystals. 2138700100021 NaI(Tl) crystals were calibrated by observing 2138700100022 coincidences between gammas and disintegrations in 2138700100023 a thin sample of B-10 in an ionisation chamber. 2138700100024 STATUS .Text, page 863. 2138700100025 HISTORY (19800221C) 2138700100026 (19800222E) 2138700100027 (20040727A) Date is corrected. Reference corrected 2138700100028 (20061205U) Reference corrected 2138700100029 CORRECTION .Corrected for distortion of spectrum due to energy 2138700100030 resolution, dead time effects, random coincidences, 2138700100031 variation of nu-bar, delayed neutrons, and a 2138700100032 substantial factor from anisotropy introduced into 2138700100033 the angular distribution of detected neutrons by the 2138700100034 absorption of fission fragments in the ionisation 2138700100035 chamber foil used for liquid scintillator calibration 2138700100036 ERR-ANALYS .A complete error analysis is given with contributions 2138700100037 from the following effects. - 2138700100038 Statistics 3.8 to 6.5 percent 2138700100039 time zero 0.1 pc 2138700100040 flight path length 0.025 pc 2138700100041 flight time 0.02 pc 2138700100042 dead time 0.31 pc 2138700100043 random coincidences 0.5 pc 2138700100044 backgrounds 0.5 pc 2138700100045 counter efficiency 0.35 pc 2138700100046 variation of nu 0.15 pc maximum. 2138700100047 Delayed neutrons 0.1 pc maximum. 2138700100048 Transmission effect 0.3 pc maximum. 2138700100049 Events in foil 0.35 pc maximum. 2138700100050 Secondary fissions 0.2 pc maximum. 2138700100051 Backing scattering 0.2 pc maximum. 2138700100052 Sample foil 0.2 pc 2138700100053 beam scatter 0.1 pc maximum. 2138700100054 Nonuniformity 0.4 pc maximum. 2138700100055 ENDBIB 53 0 2138700100056 NOCOMMON 0 0 2138700100057 ENDSUBENT 56 0 2138700199999 SUBENT 21387002 20040727 00002138700200001 BIB 2 2 2138700200002 REACTION (92-U-235(N,F),,SIG) FISSION CROSS SECTION. 2138700200003 STATUS .TEXT, PAGE 863. 2138700200004 ENDBIB 2 0 2138700200005 NOCOMMON 0 0 2138700200006 DATA 3 1 2138700200007 EN DATA DATA-ERR 2138700200008 EV B B 2138700200009 2.5300E-02 5.7200E+02 6.0000E+00 2138700200010 ENDDATA 3 0 2138700200011 ENDSUBENT 10 0 2138700299999 ENDENTRY 2 0 2138799999999