ENTRY 14668 20201207 14761466800000001 SUBENT 14668001 20201207 14761466800100001 BIB 8 12 1466800100002 TITLE A Measurement of the 25 Cross-Section for 0.53 MeV 1466800100003 Neutrons by the Manganese Solution Method 1466800100004 AUTHOR (D.L.Benedict,A.O.Hanson) 1466800100005 REFERENCE (R,CF-638,1943) 1466800100006 INSTITUTE (1USAWIS) 1466800100007 FACILITY (ACCEL,1USAWIS) The concentric electrode electrostatic 1466800100008 generator. 1466800100009 INC-SOURCE (P-LI7) The protons were accelerated to the 1466800100010 accurately measured and controlled energy of 2.27 MeV 1466800100011 (using 1.86 MeV as the threshold). 1466800100012 DETECTOR (GEMUC,FISCH) 1466800100013 HISTORY (20201207C) BP 1466800100014 ENDBIB 12 0 1466800100015 NOCOMMON 0 0 1466800100016 ENDSUBENT 15 0 1466800199999 SUBENT 14668002 20201207 14761466800200001 BIB 3 26 1466800200002 REACTION (92-U-235(N,F),,SIG) 1466800200003 METHOD (MANGB) The number of neutrons from the Li(p,n) 1466800200004 reaction for 2.27 MeV protons incident upon a lithium 1466800200005 target approximately 40 keV thick was compared with 1466800200006 the number of neutrons emitted by a 200 mc Ra-Be 1466800200007 source by the manganese solution method. The solution 1466800200008 tank used was 2 feet in diameter and 2 feet deep. The 1466800200009 strength of the Ra-Be source was taken as 1.9x10**6 1466800200010 neutrons per second but this value is subject to 1466800200011 change after recalibration by the Chicago group. 1466800200012 Determination of the Fission Rate: the two separated 1466800200013 foils, Mg-XIII-7 and Mg-C-3, were placed back to back 1466800200014 l/32 inch apart in a fission chamber which allowed 1466800200015 the simultaneous counting of the fissions due to each 1466800200016 foils This chamber has been improved by mounting the 1466800200017 first amplifier stages right below the chambers. The 1466800200018 scalar bias was set so as to count all pulses more 1466800200019 than twice the height of the alpha pulses. The 1466800200020 chamber was mounted directly in front of the target 1466800200021 at a distance of 1.864 inches from the center of the 1466800200022 foils to the center of the target. The above 1466800200023 comparison combined with a measurement of the angular 1466800200024 asymmetry of the neutrons from lithium and an 1466800200025 observation of the fissions induced in the Mg-C-3 and 1466800200026 Mg-XIII-7 gives the cross-section for 235U. 1466800200027 STATUS (TABLE) page 7. 1466800200028 ENDBIB 26 0 1466800200029 NOCOMMON 0 0 1466800200030 DATA 2 1 1466800200031 EN DATA 1466800200032 MEV B 1466800200033 0.53 1.22 1466800200034 ENDDATA 3 0 1466800200035 ENDSUBENT 34 0 1466800299999 ENDENTRY 2 0 1466899999999