ENTRY 14723 20211211 14951472300000001 SUBENT 14723001 20211211 14951472300100001 BIB 11 40 1472300100002 TITLE Measurements of nu49/nu25 1472300100003 AUTHOR (C.L.Bailey, J.M.Blair,D.H.Frisch,K.Greisen, 1472300100004 A.O.Hansen,J.M.Hush,M.Kahn,R.D.Krohn,J.L.McKibben, 1472300100005 R.G.Nuckolls,R.Perry,H.T.Richards,C.Richman, 1472300100006 R.F.T Aschek,C.M.Turner,A.C.Wahl,J.H.Williams) 1472300100007 REFERENCE (R,LA-25,1943) 1472300100008 INSTITUTE (1USALAS) 1472300100009 FACILITY (VDG,1USALAS) 1472300100010 INC-SOURCE (P-LI7) Lithium targets, approximately 75 kv thick, 1472300100011 bombarded by 1.95 MeV protons. The maximum energy of 1472300100012 the primary neutrons was therefore 0.15 MeV. These 1472300100013 primary neutrons were transformed to slow neutrons by 1472300100014 surrounding the target and detectors by either 1472300100015 paraffin or water. 1472300100016 SAMPLE The 235U samples, with which these aliquots have been 1472300100017 compared in a double fission chamber to give 11472300100018 relative fission cross section, are thin foils of 1472300100019 normal uranium containing 065, 3.54 and 10.6 1472300100020 micrograms of 235U and an enriched sample containing 1472300100021 17.9 micrograms of 235U. The 235U content of the latter1472300100022 sample was obtained by comparing it with 500- and 1472300100023 1500- microgram foils of normal alloy. For the 1472300100024 paraffin geometry pertaining to the first und third 1472300100025 experiments we have compared two aliquots of the 1472300100026 original solution containing the 239Pu sample with 1472300100027 various uranium samples. Assuming that 239Pu has a 1472300100028 half-life of 21,300 years the masses of these 1472300100029 aliquots was found to be 1.02+-0.02 and 1.60+-0.03 1472300100030 micrograms respectively. From these values and the 1472300100031 percentages of the original material in these aliquots 1472300100032 the mass of 239Pu used in the earlier experiments is 1472300100033 calculated to be 142.3+-3.7 micrograms. 1472300100034 METHOD The ratio of the number or neutrons emitted per 1472300100035 fission in 239Pu to the number of neutrons emitted per 1472300100036 fission in 235U has been measured by two different 1472300100037 methods. 1472300100038 ERR-ANALYS (ERR-S) The statistical errors are calculated from 1472300100039 the number of neutrons counted. 1472300100040 DECAY-DATA (94-PU-239,21300.YR) 1472300100041 HISTORY (20211211C) BP 1472300100042 ENDBIB 40 0 1472300100043 COMMON 1 3 1472300100044 EN-DUMMY 1472300100045 EV 1472300100046 0.0253 1472300100047 ENDCOMMON 3 0 1472300100048 ENDSUBENT 47 0 1472300199999 SUBENT 14723002 20211211 14951472300200001 BIB 3 7 1472300200002 REACTION ((94-PU-239(N,F),PAR,NU,,SPA)/ 1472300200003 (92-U-235(N,F),PAR,NU,,SPA)) 1472300200004 METHOD (REC) The first method was to count the number of 1472300200005 protons recoils from a thick paraffin layer 1472300200006 surrounding a sample of fissionable material. 1472300200007 STATUS (TABLE) pages 13,14 1472300200008 (COREL,14723003) Second method 1472300200009 ENDBIB 7 0 1472300200010 NOCOMMON 0 0 1472300200011 DATA 3 2 1472300200012 E-MIN DATA ERR-S 1472300200013 MEV NO-DIM NO-DIM 1472300200014 0.72 1.20 0.09 1472300200015 0.86 1.16 0.13 1472300200016 ENDDATA 4 0 1472300200017 ENDSUBENT 16 0 1472300299999 SUBENT 14723003 20211211 14951472300300001 BIB 3 11 1472300300002 REACTION ((94-PU-239(N,F),PAR,NU,,SPA)/ 1472300300003 (92-U-235(N,F),PAR,NU,,SPA)) 1472300300004 METHOD (REC) The second method of determining the relative 1472300300005 number of neutrons emitted from known masses of 239Pu 1472300300006 and 235U is based on an entirely different physical 1472300300007 phenomenon. In this case the fission neutrons were 1472300300008 detected by their ability to produce fission in 1472300300009 thorium, whereas the primary neutrons had energies 1472300300010 less than the 1.2 MeV fission threshold of thorium. 1472300300011 STATUS (TABLE) page 14. 1472300300012 (COREL,14723002) First method 1472300300013 ENDBIB 11 0 1472300300014 COMMON 1 3 1472300300015 E-MIN 1472300300016 MEV 1472300300017 1.2 1472300300018 ENDCOMMON 3 0 1472300300019 DATA 2 1 1472300300020 DATA ERR-S 1472300300021 NO-DIM NO-DIM 1472300300022 1.25 0.12 1472300300023 ENDDATA 3 0 1472300300024 ENDSUBENT 23 0 1472300399999 ENDENTRY 3 0 1472399999999