ENTRY 14730 20220117 14951473000000001 SUBENT 14730001 20220117 14951473000100001 BIB 10 25 1473000100002 TITLE Spontaneous fission in separated uranium isotopes 1473000100003 AUTHOR (O.Chamberlain,G.W.Farwell,E.Segre) 1473000100004 REFERENCE (R,LA-86,1944) 1473000100005 INSTITUTE (1USALAS) 1473000100006 DETECTOR (IOCH) 1473000100007 SAMPLE The samples were thin layers (0.25 mg/cm2) of U308 1473000100008 deposited electrolytically on platinum disks 0.05 mm 1473000100009 thick and 4.3 cm in diameter. The discs were spot 1473000100010 welded to copper discs of 12.7 cm diameter. A series 1473000100011 of samples was prepared out of ordinary uranium 1473000100012 (specific alpha activity 1500 alphas/mg); another 1473000100013 series of samples was of uranium of isotopic 1473000100014 composition U238:U235:U234 = 2.76:1.00:0.0044 in mass 1473000100015 (specific activity 16.44x10**3 alphas/mg*min). 1473000100016 METHOD The experiments consisted of putting certain amounts 1473000100017 of normal uranium or of uranium whose isotopic 1473000100018 composition had been changed in a known fashion in 1473000100019 ionization chambers connected to linear amplifiers, 1473000100020 and counting the fission pulses. 1473000100021 ANALYSIS Authors measured that the spontaneous fission rate of 1473000100022 238U is 24.0 +- 1.1 f/gm*hr and the spontaneous 1473000100023 fission rates of 235U and 234U are - 2.2 +- 4.6 and 1473000100024 <60 f/g*hr, respectively. 1473000100025 ERR-ANALYS (DATA-ERR) No details on sources of uncertainties. 1473000100026 HISTORY (20220117C) BP 1473000100027 ENDBIB 25 0 1473000100028 COMMON 1 3 1473000100029 DATA-ERR 1473000100030 PER-CENT 1473000100031 15.0 1473000100032 ENDCOMMON 3 0 1473000100033 ENDSUBENT 32 0 1473000199999 SUBENT 14730002 20220117 14951473000200001 BIB 4 8 1473000200002 REACTION (92-U-0(0,F),PR,NU,,,DERIV) 1473000200003 REL-REF (R,,W.Maurer+,J,ZP,121,285,1943) 1473000200004 ANALYSIS From result of Maurer and Pose that 1 gram of uranium 1473000200005 emits 50 neutrons per hour spontaneous fission nubar 1473000200006 was deduced. 1473000200007 STATUS (TABLE) page 9. 1473000200008 (COREL,14730003) Based on Fermi's result 1473000200009 (COREL,14730004) Based on Scharff-Goldhaber result 1473000200010 ENDBIB 8 0 1473000200011 NOCOMMON 0 0 1473000200012 DATA 1 1 1473000200013 DATA 1473000200014 PRT/FIS 1473000200015 2.1 1473000200016 ENDDATA 3 0 1473000200017 ENDSUBENT 16 0 1473000299999 SUBENT 14730003 20220117 14951473000300001 BIB 4 8 1473000300002 REACTION (92-U-0(0,F),PR,NU,,,DERIV) 1473000300003 REL-REF (R,,E.Fermi,W,FERMI,1944) 1473000300004 ANALYSIS From result of Fermi that 1 gram of uranium emits 54 1473000300005 neutrons per hour spontaneous fission nubar was 1473000300006 deduced. 1473000300007 STATUS (TABLE) page 9. 1473000300008 (COREL,14730002) Based on Maurer-Pose result 1473000300009 (COREL,14730004) Based on Scharff-Goldhaber result 1473000300010 ENDBIB 8 0 1473000300011 NOCOMMON 0 0 1473000300012 DATA 1 1 1473000300013 DATA 1473000300014 PRT/FIS 1473000300015 2.2 1473000300016 ENDDATA 3 0 1473000300017 ENDSUBENT 16 0 1473000399999 SUBENT 14730004 20220117 14951473000400001 BIB 4 8 1473000400002 REACTION (92-U-0(0,F),PR,NU,,,DERIV) 1473000400003 REL-REF (R,,G.Scharff-Goldhaber+,R,CN-1463,1942) 1473000400004 ANALYSIS From result of Scharff-Goldhaber that 1 gram of uranium1473000400005 emits 63.75 neutrons per hour spontaneous fission nubar1473000400006 was deduced. 1473000400007 STATUS (TABLE) page 9. 1473000400008 (COREL,14730002) Based on Maurer-Pose result 1473000400009 (COREL,14730003) Based on Fermi's result 1473000400010 ENDBIB 8 0 1473000400011 NOCOMMON 0 0 1473000400012 DATA 1 1 1473000400013 DATA 1473000400014 PRT/FIS 1473000400015 2.95 1473000400016 ENDDATA 3 0 1473000400017 ENDSUBENT 16 0 1473000499999 ENDENTRY 4 0 1473099999999