ENTRY 14664 20201207 14761466400000001 SUBENT 14664001 20201207 14761466400100001 BIB 7 14 1466400100002 TITLE The Energy of Fission Neutrons 1466400100003 AUTHOR (R.F.Christy,J.H.Manley) 1466400100004 REFERENCE (R,CF-209,1942) 1466400100005 REL-REF (R,,N.P.Heydenburg,W,HEYDENBURG,1942) C-D, D-D and Ra- 1466400100006 Be neutrons exponential absorption coefficient in 1466400100007 water. 1466400100008 (R,,C.C.Gamortsfolder,T,GAMORTSFOLDER,1942) Rd Th-Be, 1466400100009 Rd Th-D, Y-Be neutrons (photo), Ra-Be exponential 1466400100010 absorption coefficient in water. 1466400100011 (R,,Anderson,W,ANDERSON,1942) Ra-Be neutrons 1466400100012 exponential absorption coefficient in water. 1466400100013 INSTITUTE (1USACHI) 1466400100014 INC-SOURCE (D-C12,D-D,RA-BE,TH-BE,PHOTO) 1466400100015 HISTORY (20201207C) BP 1466400100016 ENDBIB 14 0 1466400100017 NOCOMMON 0 0 1466400100018 ENDSUBENT 17 0 1466400199999 SUBENT 14664002 20201207 14761466400200001 BIB 4 17 1466400200002 REACTION (92-U-235(N,F)0-NN-1,PR,KE,,,DERIV) 1466400200003 ANALYSIS Absorption coefficients (alpha) in water for 1466400200004 different neutron energies in water were analyzed and 1466400200005 fitted as exponent at large distances. The data 1466400200006 (Manhattan project report C-121) with a plane source 1466400200007 in paraffin and not in water. The data were fitted 1466400200008 numerically with -Ei(alpha z) where z is coordinate. 1466400200009 The best fit for z less 25 cm was obtained with 1466400200010 alpha=0.162. That value would correspond to 2.2 MeV 1466400200011 neutrons using the absorption curves. It is very 1466400200012 difficult to locate the C-121 report. However, Ra-Be 1466400200013 neutron sources were used in the early reactor piles, 1466400200014 so the C-121 report incident neutron energy is 1466400200015 assumed as 3.6 MeV. 1466400200016 ERR-ANALYS (DATA-ERR) Upper limit on uncertainty if the 1466400200017 experiments are reasonably accurate. 1466400200018 STATUS (TABLE) page 3. 1466400200019 ENDBIB 17 0 1466400200020 NOCOMMON 0 0 1466400200021 DATA 3 1 1466400200022 EN-APRX DATA DATA-ERR 1466400200023 MEV MEV MEV 1466400200024 3.6 2.2 0.2 1466400200025 ENDDATA 3 0 1466400200026 ENDSUBENT 25 0 1466400299999 ENDENTRY 2 0 1466499999999