ENTRY 21198 20090110 22072119800000001 SUBENT 21198001 20090110 22072119800100001 BIB 12 53 2119800100002 INSTITUTE (2UK ALD) P.H.White. 2119800100003 (2UK NPL) E.J.Axton. 2119800100004 REFERENCE (J,JNE,22,73,196802) 2119800100005 AUTHOR (P.H.White, E.J.Axton) 2119800100006 TITLE -Measurement of the number of neutrons per fission for 2119800100007 Cf-252- 2119800100008 SAMPLE Thin (less than 0.25 mg/cm**2) foil on 0.005 cm thick 2119800100009 platinum backing. 2119800100010 METHOD (MANGB) Manganese bath to measure absolute neutron 2119800100011 emission rate in NPL . 2119800100012 (ABSFY) Fission fragment counting to determine fission 2119800100013 rate. 2119800100014 DETECTOR (SOLST) Fission fragments detected in silicon surface 2119800100015 barrier detector, biassed to 25 MeV. 2119800100016 (IOCH) Two 2-pi counters - gridded ion chamber filled 2119800100017 with argon/10% methane and parallel plate ionization 2119800100018 chamber filled with xenon/10% carbon dioxide- to 2119800100019 measure the fraction of fragments backscattered from 2119800100020 platinum backing. 2119800100021 EXP-YEAR (1966) 2119800100022 STATUS (NDD) From NEUDADA. 2119800100023 CORRECTION .No correction for backscattering from platinum was 2119800100024 made but a contribution of 0.5 % was added to the 2119800100025 final error to allow for the possibility. 2119800100026 ERR-ANALYS -Neutron measurement included: 2119800100027 Counting statistics -0.2%( standard deviation) and 2119800100028 Systematic errors : 2119800100029 (ERR-1) In cross-section ratios 0.25%, 2119800100030 (ERR-2) Counter efficiency 0.30%, 2119800100031 (ERR-3) Fast neutron escape 0.02%, 2119800100032 (ERR-4) Fast neutron losses due to charged particle 2119800100033 reactions 0.10%, 2119800100034 (ERR-10) Neutron capture in source container 0.05%, 2119800100035 (ERR-6) Manganese resonance capture 0.10%. 2119800100036 -Fission measurement included: 2119800100037 Counting statistics 0.2% (standard deviation) and 2119800100038 Systematic errors : 2119800100039 (ERR-7) In solid angle 0.15%, 2119800100040 (ERR-8) Backscattering 0.50%, 2119800100041 (ERR-9) Uncertainty in time distribution of Cf-252 2119800100042 loss due to self-transfer 0.40%. 2119800100043 -Other systematic errors : 2119800100044 (+ERR-5) Uncertainty in delayed neutron fraction +0.03%2119800100045 (ERR-11) Chemical and isotopic purity 0.1%. 2119800100046 (ERR-S) Total statistical error 0.3 % (random), 2119800100047 (ERR-SYS) Total systematic error 0.79%. 2119800100048 (ERR-T) Total error obtained by compounding the random 2119800100049 and systematic errors quadratically. 2119800100050 HISTORY (19791129T) 2119800100051 (19800110E) 2119800100052 (20090110U) M.M. BIB and COMMON information was added. 2119800100053 Dates were corrected for 4-digits year. 2119800100054 Free text was corrected to be human-readable. 2119800100055 ENDBIB 53 0 2119800100056 COMMON 13 9 2119800100057 ERR-1 ERR-2 ERR-3 ERR-4 ERR-10 ERR-6 2119800100058 ERR-7 ERR-8 ERR-9 +ERR-5 ERR-11 ERR-S 2119800100059 ERR-SYS 2119800100060 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 2119800100061 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 2119800100062 PER-CENT 2119800100063 0.25 0.30 0.02 0.10 0.05 0.10 2119800100064 0.15 0.50 0.40 0.03 0.1 0.3 2119800100065 0.79 2119800100066 ENDCOMMON 9 0 2119800100067 ENDSUBENT 66 0 2119800199999 SUBENT 21198002 20090110 22072119800200001 BIB 6 15 2119800200002 REACTION 1(98-CF-252(0,F),,NU) 2119800200003 2(98-CF-252(0,F),PR,NU,,,DERIV) 2119800200004 ASSUMED 2(ASSUM,98-CF-252(0,F),DL,NU) Delayed NU taken from 2119800200005 S.A.Cox+, Phys.Rev.,112,(1958),960. 2119800200006 REL-REF (R,13690003,S.A.Cox+,J,PR,112,960,1958) 2119800200007 ANALYSIS Measured neutron output and the measured fission rate 2119800200008 give a value for the average total number of neutrons 2119800200009 per fission. Allowing ASSUM value of delayed neutron 2119800200010 per fission, the average number of prompt neutrons per 2119800200011 fission was obtained. 2119800200012 STATUS .Data from text of publication, p.76. 2119800200013 HISTORY (20090110A) DATA-ERR -> ERR-T according to authors 2119800200014 comment, p.76. 2119800200015 Data units were corrected : NO-DIM -> PRT/FIS . 2119800200016 DERIV was added in REACTION 2 . 2119800200017 ENDBIB 15 0 2119800200018 NOCOMMON 0 0 2119800200019 DATA 5 1 2119800200020 DATA 1DATA 2ERR-T 2ASSUM 2ASSUM-ERR 2 2119800200021 PRT/FIS PRT/FIS PRT/FIS PRT/FIS PRT/FIS 2119800200022 3.796 3.787 3.1000E-02 8.6000E-03 1.0000E-03 2119800200023 ENDDATA 3 0 2119800200024 ENDSUBENT 23 0 2119800299999 ENDENTRY 2 0 2119899999999