ENTRY 14669 20201207 14761466900000001 SUBENT 14669001 20201207 14761466900100001 BIB 8 15 1466900100002 TITLE Fission cross section of 94239 for 220 keV neutrons 1466900100003 and Ra plus Be neutrons 1466900100004 AUTHOR (E.Segre,C.Wiegand) 1466900100005 REFERENCE (R,LA-21,1943) 1466900100006 INSTITUTE (1USALAS) 1466900100007 DETECTOR (IOCH) 1466900100008 METHOD (COINC) A coincidence chamber with a sample mounted 1466900100009 on a thin film, taking advantage of the fact that the 1466900100010 fission fragments fly apart in opposite directions. 1466900100011 The two samples were put successively in the 1466900100012 ionization chamber, the chamber was filled with 1466900100013 nitrogen, and an yttrium-plus-beryllium source was 1466900100014 put in a standard position above the chamber. 1466900100015 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1466900100016 HISTORY (20201207C) BP 1466900100017 ENDBIB 15 0 1466900100018 NOCOMMON 0 0 1466900100019 ENDSUBENT 18 0 1466900199999 SUBENT 14669002 20201207 14761466900200001 BIB 5 9 1466900200002 REACTION ((94-PU-239(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1466900200003 INC-SOURCE (PHOTO) A photoneutron source giving 220 keV neutrons. 1466900200004 SAMPLE A sample of enriched uranium containing 35.5 microg of 1466900200005 235U, prepared by the Berkeley method, was used as a 1466900200006 standard, and a sample containing 16.8 microg of 1466900200007 239Pu as determined by its alpha activity was used 1466900200008 for the determination of sigma 239Pu. 1466900200009 DECAY-DATA (94-PU-239,21300.YR) 1466900200010 STATUS (TABLE) page 5. 1466900200011 ENDBIB 9 0 1466900200012 NOCOMMON 0 0 1466900200013 DATA 3 1 1466900200014 EN DATA DATA-ERR 1466900200015 KEV NO-DIM NO-DIM 1466900200016 220.0 1.14 0.13 1466900200017 ENDDATA 3 0 1466900200018 ENDSUBENT 17 0 1466900299999 SUBENT 14669003 20201207 14761466900300001 BIB 6 17 1466900300002 REACTION ((94-PU-239(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1466900300003 INC-SOURCE (PHOTO) A photoneutron source giving 220 keV neutrons 1466900300004 was used to generate thermal neutron flux. 1466900300005 SAMPLE A sample of enriched uranium containing 35.5 microg of 1466900300006 235U, prepared by the Berkeley method, was used as a 1466900300007 standard, and a sample containing 16.8 microg of 1466900300008 239Pu as determined by its alpha activity was used 1466900300009 for the determination of sigma 239Pu. 1466900300010 METHOD Since thickness of the samples or inequality in their 1466900300011 distribution is always a possible cause of error in 1466900300012 measurements of this type we checked that our samples 1466900300013 give the accepted value of sigma 239Pu/sigma 235U for 1466900300014 thermal neutrons. This was done by surrounding the 1466900300015 whole apparatus with a thick paraffin layer and 1466900300016 measuring cadmium differences. 1466900300017 DECAY-DATA (94-PU-239,21300.YR) 1466900300018 STATUS (TABLE) page 5. 1466900300019 ENDBIB 17 0 1466900300020 NOCOMMON 0 0 1466900300021 DATA 3 1 1466900300022 EN-DUMMY DATA DATA-ERR 1466900300023 EV NO-DIM NO-DIM 1466900300024 0.0253 1.22 0.2 1466900300025 ENDDATA 3 0 1466900300026 ENDSUBENT 25 0 1466900399999 SUBENT 14669004 20201207 14761466900400001 BIB 4 6 1466900400002 REACTION ((92-U-238(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1466900400003 INC-SOURCE (RA-BE) Average neutron energy: 3.6 MeV (13.2 MeV max).1466900400004 SAMPLE A sample containing 955 microg of 238U, 0.2 microg of 1466900400005 235U and 0.002 microg of 234U; a sample containing 77 1466900400006 microg of 238U, 129 microg of 235U. 1466900400007 STATUS (TABLE) page 6. 1466900400008 ENDBIB 6 0 1466900400009 NOCOMMON 0 0 1466900400010 DATA 3 1 1466900400011 EN-APRX DATA DATA-ERR 1466900400012 MEV NO-DIM NO-DIM 1466900400013 3.6 0.323 0.016 1466900400014 ENDDATA 3 0 1466900400015 ENDSUBENT 14 0 1466900499999 SUBENT 14669005 20201207 14761466900500001 BIB 4 8 1466900500002 REACTION ((92-U-234(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1466900500003 INC-SOURCE (RA-BE) Average neutron energy: 3.6 MeV (13.2 MeV max).1466900500004 SAMPLE A sample containing 955 microg of 238U, 0.2 microg of 1466900500005 235U and 0.002 microg of 234U; a sample containing 77 1466900500006 microg of 238U, 129 microg of 235U, 1.03 microg of 1466900500007 234U prepared and analyzed in Berkeley and a sample 1466900500008 of 234U containing 13.4 microg of pure 234U. 1466900500009 STATUS (TABLE) page 6. 1466900500010 ENDBIB 8 0 1466900500011 NOCOMMON 0 0 1466900500012 DATA 3 1 1466900500013 EN-APRX DATA DATA-ERR 1466900500014 MEV NO-DIM NO-DIM 1466900500015 3.6 0.7 0.15 1466900500016 ENDDATA 3 0 1466900500017 ENDSUBENT 16 0 1466900599999 SUBENT 14669006 20201207 14761466900600001 BIB 4 6 1466900600002 REACTION ((94-PU-239(N,F),,SIG)/(92-U-235(N,F),,SIG)) 1466900600003 INC-SOURCE (RA-BE) Average neutron energy: 3.6 MeV (13.2 MeV max).1466900600004 SAMPLE A sample containing 955 microg of 238U, 0.2 microg of 1466900600005 235U and 0.002 microg of 234U; a sample containing 77 1466900600006 microg of 238U, 129 microg of 235U. 1466900600007 STATUS (TABLE) page 6. 1466900600008 ENDBIB 6 0 1466900600009 NOCOMMON 0 0 1466900600010 DATA 3 1 1466900600011 EN-APRX DATA DATA-ERR 1466900600012 MEV NO-DIM NO-DIM 1466900600013 3.6 1.57 0.16 1466900600014 ENDDATA 3 0 1466900600015 ENDSUBENT 14 0 1466900699999 ENDENTRY 6 0 1466999999999