ENTRY 21409 20211224 23062140900000001 SUBENT 21409001 20211224 23062140900100001 BIB 14 49 2140900100002 TITLE Mass spectrometric measurements of the ratio of 2140900100003 thermal neutron capture to fission for Pu-241 2140900100004 AUTHOR (M.J.Cabell,M.Wilkins) 2140900100005 INSTITUTE (2UK HAR) Chemistry division. 2140900100006 REFERENCE (J,JIN,27,2481,1965) Data superseded. 2140900100007 (C,66PARIS,2,3,1966) Revised final data. 2140900100008 (R,AERE-R-5166,1966) Superseded. 2140900100009 FACILITY (REAC,2UK HAR) PLUTO reactor. 2140900100010 INC-SOURCE (REAC) Irradiations were in the flux scanning tube 2140900100011 of the B2 fuel element for 48.35 days. 2140900100012 INC-SPECT The PLUTO spectrum is Maxwellian with a temperature 2140900100013 of 106 degrees and with a high epi-thermal index, 2140900100014 ranging from 0.041 to 0.087 2140900100015 SAMPLE Nitric acid solutions of mixtures of four highly 2140900100016 enriched isotopes of plutonium, precipitated onto 2140900100017 silica and sealed in silica phials under pressure. 2140900100018 METHOD (CHSEP,ASEP) Mass spectroscopy using an A.E.I. Type 2140900100019 M.S.5 Spectrometer, with about 0.1 micro-g plutonium 2140900100020 on a tungsten filament surface ionisation source. 2140900100021 After irradiation samples were allowed to cool for 2140900100022 six months, then plutonium was chemically seperated 2140900100023 and used for the isotopic composition changes. 2140900100024 ANALYSIS Value derived from changes in isotopic composition 2140900100025 arising from neutron capture and fission. 2140900100026 All measured ratios involving Pu-241 were corrected 2140900100027 for radio-active decay using a half life 2140900100028 of 13.29 +- 0.06 years. 2140900100029 - Note that this differs considerably from 2140900100030 later acceped values but was not considered in the 2140900100031 Re-analysis of 66PARIS. - 2140900100032 MONITOR (27-CO-59(N,G)27-CO-60,,SIG) 2200 m/sec 2140900100033 CORRECTION Correction for production of Pu-242 via Pu-241 decay 2140900100034 to Am-241 followed by capture to Am-242-g then decay 2140900100035 to Pu-242 was not included in the original analysis, 2140900100036 but is included in the revised analysis in 66PARIS. 2140900100037 ERR-ANALYS (ERR-T) Total error 2140900100038 (ERR-1) Uncertainty in determination of reactor 2140900100039 spectrum value of alpha (5.5%), 2140900100040 (ERR-S) Statistical error (1.9%), 2140900100041 (ERR-2) Uncertainty in mass discrimination in 2140900100042 spectrometer (0.1%), 2140900100043 (ERR-3) Uncertainty in neutron spectrum temperature 2140900100044 and epi-thermal index (0.1%). 2140900100045 (ERR-4) Uncertainty is included from errors in 2140900100046 conversion factors, Westcott factors. 2140900100047 HISTORY (19800303C) 2140900100048 (20211224A) SD:Updated to new date formats,lower case. 2140900100049 Corrections in all Subents. SF4=Co-60-G+M -> Co-60; 2140900100050 SF6=SIG/SUM -> SIG in MONITOR. 2140900100051 ENDBIB 49 0 2140900100052 COMMON 6 3 2140900100053 MONIT ERR-1 ERR-2 ERR-3 ERR-4 ERR-S 2140900100054 B PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 2140900100055 37.2 5.5 0.1 0.1 1. 1.9 2140900100056 ENDCOMMON 3 0 2140900100057 ENDSUBENT 56 0 2140900199999 SUBENT 21409002 20211224 23062140900200001 BIB 3 3 2140900200002 REACTION (94-PU-241(N,ABS),,ALF) 2200 m/sec value. 2140900200003 STATUS (TABLE) Text on p.14 of 66PARIS,Vol.2,p.3(1966) 2140900200004 HISTORY (20211224U) SD: STATUS updated. DATA-ERR -> ERR-T. 2140900200005 ENDBIB 3 0 2140900200006 NOCOMMON 0 0 2140900200007 DATA 3 1 2140900200008 EN DATA ERR-T 2140900200009 EV NO-DIM NO-DIM 2140900200010 2.530E-02 0.339 0.031 2140900200011 ENDDATA 3 0 2140900200012 ENDSUBENT 11 0 2140900299999 ENDENTRY 2 0 2140999999999