ENTRY 14733 20220118 149614733 0 1 SUBENT 14733001 20220118 149614733 1 1 BIB 9 17 14733 1 2 TITLE The ratio of the fission cross sections of 49 and 25 14733 1 3 for thermal neutrons and the ration [1+alpha(49)]/ 14733 1 4 [1+alpha(25)] 14733 1 5 AUTHOR (J.W.Dewire,R.R.Wilson,W.D.Woodward) 14733 1 6 REFERENCE (R,LA-103,1944) 14733 1 7 REL-REF (R,14734001,E.E.Anderson+,S,LA-91,1944) 239Pu 14733 1 8 absorption cross section. 14733 1 9 INSTITUTE (1USALAS) 14733 1 10 FACILITY (CYCLO,1USALAS) 14733 1 11 INC-SOURCE (D-BE) A thermalized neutron flux of about 2*10**5 14733 1 12 neutrons/cm2/sec at the center of the 11'*7'*6'8" 14733 1 13 graphite block at the cyclotron. 14733 1 14 DETECTOR (IOCH) The comparison chamber consisted of two 14733 1 15 parallel plate ionization chambers having a common 14733 1 16 high voltage electrode, on which the samples were 14733 1 17 placed. 14733 1 18 HISTORY (20220118C) BP 14733 1 19 ENDBIB 17 0 14733 1 20 COMMON 1 3 14733 1 21 EN-DUMMY 14733 1 22 EV 14733 1 23 0.0253 14733 1 24 ENDCOMMON 3 0 14733 1 25 ENDSUBENT 24 0 14733 199999 SUBENT 14733002 20220118 149614733 2 1 BIB 5 14 14733 2 2 REACTION ((94-PU-239(N,F),,SIG,,SPA)/(92-U-235(N,F),,SIG,,SPA)) 14733 2 3 SAMPLE Six foils of 235U and four foils of 239Pu were used 14733 2 4 in the experiment. All the foils were deposited on 1 14733 2 5 or 2 mil Pt. All the weights are based on a half life 14733 2 6 for 239Pu of 24,400 years. 14733 2 7 ERR-ANALYS (DATA-ERR) In order to find any systematic errors in 14733 2 8 counting, a 239Pu foil and a 235U foil were compared 14733 2 9 under conditions obtained by separately interchanging 14733 2 10 scalars, amplifiers, and foils, and by moving the 14733 2 11 chamber within the block. No significant change in 14733 2 12 the counting ratio were detected. No further details 14733 2 13 on how the given uncertainty was determined. 14733 2 14 DECAY-DATA (94-PU-239,24400.YR) 14733 2 15 STATUS (TABLE) page 5. 14733 2 16 ENDBIB 14 0 14733 2 17 NOCOMMON 0 0 14733 2 18 DATA 2 1 14733 2 19 DATA DATA-ERR 14733 2 20 NO-DIM NO-DIM 14733 2 21 1.40 0.02 14733 2 22 ENDDATA 3 0 14733 2 23 ENDSUBENT 22 0 14733 299999 SUBENT 14733003 20220118 149614733 3 1 BIB 4 10 14733 3 2 REACTION (((94-PU-239(N,ABS),,SIG,,SPA)/ 14733 3 3 (92-U-235(N,ABS),,SIG,,SPA))/ 14733 3 4 ((94-PU-239(N,F),,SIG,,SPA)/(92-U-235(N,F),,SIG,,SPA)))14733 3 5 ANALYSIS The following relation was used: [1+alpha(239Pu)]/ 14733 3 6 [1+alpha(235U)] = ((sigma abs(239Pu)/sigma abs(235U))/ 14733 3 7 (sigmaf(235U)/sigmaf(239Pu))). 14733 3 8 ASSUMED (ASSUM1,94-PU-239(N,ABS),,SIG) 14733 3 9 (ASSUM2,92-U-235(N,ABS),,SIG) 14733 3 10 STATUS (DEP,14733002) 14733 3 11 (TABLE) page 7. 14733 3 12 ENDBIB 10 0 14733 3 13 NOCOMMON 0 0 14733 3 14 DATA 3 1 14733 3 15 DATA ASSUM1 ASSUM2 14733 3 16 NO-DIM B B 14733 3 17 1.29 1056.0 640.0 14733 3 18 ENDDATA 3 0 14733 3 19 ENDSUBENT 18 0 14733 399999 ENDENTRY 3 0 1473399999999