ENTRY 13385 20191212 14631338500000001 SUBENT 13385001 20191212 14631338500100001 BIB 8 26 1338500100002 TITLE The fission yields of the cesium isotopes formed in 1338500100003 the thermal neutron fission of U235 and the neutron 1338500100004 absorption cross section of Xe-135 1338500100005 AUTHOR (J.A.Petruska,E.A.Melaika,R.H.Tomlinson) 1338500100006 REFERENCE (J,CJP,33,640,1955) 1338500100007 #doi:10.1139/p55-080 1338500100008 INSTITUTE (1CANMCM) 1338500100009 FACILITY (REAC,1CANCRC) NRX (Chalk River) reactor. 1338500100010 METHOD (CHSEP,EXTB) Two samples of natural uranium metal 1338500100011 were irradiated with thermal neutrons in the N.R.X. 1338500100012 The uranium was dissolved in freshly distilled nitric 1338500100013 acid and, where isotope dilution was required, 1338500100014 known amounts of natural Cs (Cs133) were added to 1338500100015 aliquots of this solution. The uranium was separated 1338500100016 from the fission products by precipitation of uranium 1338500100017 tetroxide from a neutral solution of the nitrate 1338500100018 using hydrogen peroxide as precipitant. The 1338500100019 supernatant solution containing most of the fission 1338500100020 products was concentrated by evaporation and 1338500100021 transferred I directly to the ion source filament of 1338500100022 a 90 degrees sector mass spectrometer. 1338500100023 STATUS (TABLE) Table II, page 647. 1338500100024 HISTORY (19891211C) VM 1338500100025 (20191212A) BP: Updated to new date formats, lower 1338500100026 case. Corrections according last EXFOR rules1338500100027 and Dict. 1338500100028 ENDBIB 26 0 1338500100029 COMMON 1 3 1338500100030 EN-DUMMY 1338500100031 EV 1338500100032 0.0253 1338500100033 ENDCOMMON 3 0 1338500100034 ENDSUBENT 33 0 1338500199999 SUBENT 13385002 20191212 14631338500200001 BIB 3 12 1338500200002 REACTION (92-U-235(N,F)55-CS-133,CUM,FY,,MXW) 1338500200003 METHOD The cumulative yield of Cs133 has been determined 1338500200004 from measurements of the number of cesium atoms 1338500200005 produced during a given irradiation and a knowledge 1338500200006 of the extent of the U235 fission. The number of 1338500200007 cesium atoms produced was measured with the mass 1338500200008 spectrometer using isotope dilution techniques.The 1338500200009 number of U235 fissions was calculated from the 1338500200010 change in the B10/B11 ratio in a simultaneously 1338500200011 irradiated boron flux monitor: 5-B-10(N,A)3-LI-7 and 1338500200012 the known ratio of the neutron fission cross section. 1338500200013 HISTORY (20191212A) BP: Added method description. 1338500200014 ENDBIB 12 0 1338500200015 NOCOMMON 0 0 1338500200016 DATA 1 1 1338500200017 DATA 1338500200018 PC/FIS 1338500200019 6.59 1338500200020 ENDDATA 3 0 1338500200021 ENDSUBENT 20 0 1338500299999 SUBENT 13385003 20191212 14631338500300001 BIB 7 11 1338500300002 REACTION (92-U-235(N,F)ELEM/MASS,CUM,FY,,MXW) 1338500300003 REL-REF (R,,F.W.Walker,R,AECL-3037,1972) Updated T1/2 for 137Cs1338500300004 MONITOR (92-U-235(N,F)55-CS-133,CUM,FY,,MXW) 1338500300005 METHOD The yields have been normalized to the measured 6.59% 1338500300006 absolute yield of Cs133. 1338500300007 FLAG (1.) Not corrected for delayed neutron emission. 1338500300008 COMMENT The reduction from the published 6.15% to 6.10% 137Cs 1338500300009 FY: 137Cs decreased 0.8% for change in decay 1338500300010 correction by change of half life of 137Cs from 26.6 1338500300011 to 30.2 years per Walker, AECL-3037, part II (1972). 1338500300012 HISTORY (20191212A) BP: Updated entry. 1338500300013 ENDBIB 11 0 1338500300014 COMMON 1 3 1338500300015 MONIT 1338500300016 PC/FIS 1338500300017 6.59 1338500300018 ENDCOMMON 3 0 1338500300019 DATA 4 2 1338500300020 MASS ELEMENT DATA FLAG 1338500300021 NO-DIM NO-DIM PC/FIS NO-DIM 1338500300022 135. 55. 6.41 1338500300023 137. 55. 6.10 1. 1338500300024 ENDDATA 4 0 1338500300025 ENDSUBENT 24 0 1338500399999 ENDENTRY 3 0 1338599999999