ENTRY 14666 20201207 14761466600000001 SUBENT 14666001 20201207 14761466600100001 BIB 12 34 1466600100002 TITLE A Measurement of Fission Cross-Sections by the Use of 1466600100003 a Coincidence Proportional Counter 1466600100004 AUTHOR (A.O.Hanson) 1466600100005 REFERENCE (R,CF-618,1943) 1466600100006 REL-REF (I,,J.M.Blair+,R,CF-617,1943) The construction and 1466600100007 operation of proportional counter. 1466600100008 INSTITUTE (1USAWIS) 1466600100009 FACILITY (ACCEL,1USAWIS) 1466600100010 INC-SOURCE (P-LI7) 1466600100011 DETECTOR (PROPC,FISCH) The c-p (coincidence-proportional) 1466600100012 counter and alternately the fission chamber was 1466600100013 placed in front of the target so that the face of the 1466600100014 paraffin radiator and the center of the fission 1466600100015 chamber was at the same definite distance in front of 1466600100016 the target chamber. 1466600100017 SAMPLE The factor 3.5 is the average ratio of the mass of 28 1466600100018 to the mass of 25 in the Mg-XVII-B-6 samples. 1466600100019 METHOD (REC,COINC) Measurement of the 25 and 28 cross- 1466600100020 sections were made using the neutrons from the 1466600100021 Li(p,n) reaction. The determination of the neutron 1466600100022 flux through the samples was made by the use of a 1466600100023 coincidence-proportional counter for measuring the 1466600100024 number of proton recoils from thin paraffin films of 1466600100025 accurately known weights. Three different runs were 1466600100026 made at different times with c-p data taken between 1466600100027 them. The first run was taken with the Mg-XVI-B-7 and 1466600100028 the Mg-C-3 samples, the second with Mg-XVII-B-5 and 1466600100029 Mg-XVII-B-6, and the third with Mg-XVII-B-6 and 1466600100030 Al-XIV-4. 1466600100031 CORRECTION Approximate corrections have been made for the 1466600100032 effective solid angle of the recoil counter and for 1466600100033 the reduction of fission counts due to absorption in 1466600100034 the samples. 1466600100035 HISTORY (20201207C) BP 1466600100036 ENDBIB 34 0 1466600100037 NOCOMMON 0 0 1466600100038 ENDSUBENT 37 0 1466600199999 SUBENT 14666002 20201207 14761466600200001 BIB 3 5 1466600200002 REACTION (92-U-235(N,F),,SIG) 1466600200003 COMMENT Author's summary: It is seen that the 235U 1466600200004 cross section is essentially constant for neutron 1466600200005 energies above 0.5 MeV and has a value of 1.66 b. 1466600200006 STATUS (CURVE) page 11. 1466600200007 ENDBIB 5 0 1466600200008 NOCOMMON 0 0 1466600200009 DATA 2 23 1466600200010 EN DATA 1466600200011 MEV B 1466600200012 0.122 3.179 1466600200013 0.165 2.892 1466600200014 0.227 2.515 1466600200015 0.243 2.349 1466600200016 0.293 2.169 1466600200017 0.313 2.107 1466600200018 0.379 1.707 1466600200019 0.478 1.492 1466600200020 0.481 1.232 1466600200021 0.543 1.650 1466600200022 0.543 1.484 1466600200023 0.690 1.755 1466600200024 0.691 1.611 1466600200025 0.814 1.694 1466600200026 0.814 1.460 1466600200027 0.932 1.830 1466600200028 0.932 1.699 1466600200029 1.105 1.706 1466600200030 1.226 1.545 1466600200031 1.229 1.478 1466600200032 1.385 1.704 1466600200033 1.708 1.595 1466600200034 1.798 1.501 1466600200035 ENDDATA 25 0 1466600200036 ENDSUBENT 35 0 1466600299999 SUBENT 14666003 20201207 14761466600300001 BIB 3 4 1466600300002 REACTION (92-U-238(N,F),,SIG) 1466600300003 COMMENT Author's summary: The 238U cross section rises from 1466600300004 zero at 1 MeV to 0.45 b at 1.8 MeV. 1466600300005 STATUS (CURVE) page 11. 1466600300006 ENDBIB 4 0 1466600300007 NOCOMMON 0 0 1466600300008 DATA 2 6 1466600300009 EN DATA 1466600300010 MEV B 1466600300011 1.105 0.010 1466600300012 1.239 0.044 1466600300013 1.418 0.149 1466600300014 1.544 0.374 1466600300015 1.699 0.423 1466600300016 1.797 0.439 1466600300017 ENDDATA 8 0 1466600300018 ENDSUBENT 17 0 1466600399999 ENDENTRY 3 0 1466699999999