ENTRY L0222 20171018 L034L022200000001 SUBENT L0222001 20171018 L034L022200100001 BIB 10 39 L022200100002 TITLE Photofission cross-section ratio measurement of L022200100003 235U/238U using monoenergetic photons in the energy L022200100004 range of 9.0 - 16.6 MeV L022200100005 AUTHOR (Krishichayan,Megha Bhike,S.W.Finch,C.R.Howell, L022200100006 A.P.Tonchev,W.Tornow) L022200100007 INSTITUTE (1USADKE,1USATNL,1USALRL) L022200100008 REFERENCE (J,NIM/A,854,40,2017) L022200100009 FACILITY (SRING,1USATNL) Measurements were carried out at the L022200100010 High Intensity Gamma-Ray Source (HIgS) facility L022200100011 located on the campus of Duke University L022200100012 SAMPLE (92-U-235,ENR=0.99835) mass = (160.36+-1.60) mu-g L022200100013 (92-U-238,ENR=0.99954) mass = (121.90+-1.22) mu-g L022200100014 The reference foils of 235U and 238U are electroplated L022200100015 on 0.013 cm thick Ti disks. The active area of the L022200100016 deposit was 1.27 cm in diameter, which is about 7.0 mm L022200100017 smaller than the gamma beam diameter at the target. L022200100018 INC-SOURCE (LCS) The facility has a 0.24-1.2 GeV storage ring L022200100019 where quasi-monoenergetic gamma-beam is produced by L022200100020 the intracavity Compton back-scattering of the free L022200100021 electron laser photons from the electron bunches. L022200100022 For this experiment 450 and 540 nm FEL wavelength L022200100023 settings and 400 - 650 MeV electron energy settings wasL022200100024 used to provide high-energy photon beams between 8.0 L022200100025 and 17.0 MeV. L022200100026 DETECTOR (FISCH) Dual fission ionization chamber was used. L022200100027 Reference foils of 235U and 238U were used in the L022200100028 downstream (FC1) and upstream (FC2) fission chamber, L022200100029 respectively. By taking the ratio of the number of L022200100030 fissions in each chamber, one can remove the necessity L022200100031 of knowing the photon flux, as the same collimated L022200100032 photon flux is seen by both of the chambers. P-10 gass L022200100033 -(90% argon and 10% methane) was used as the DFC L022200100034 fill gas. L022200100035 ANALYSIS Pulse-height fission spectra produced by the DFC duringL022200100036 photon irradiation were each integrated to give the L022200100037 total number of fissions measured in the individual L022200100038 chamber for a given photon energy. From these numbers, L022200100039 the fission cross-section ratio was deduced L022200100040 HISTORY (20171003C) Compiled by S.H. L022200100041 ENDBIB 39 0 L022200100042 NOCOMMON 0 0 L022200100043 ENDSUBENT 42 0 L022200199999 SUBENT L0222002 20171018 L034L022200200001 BIB 3 7 L022200200002 REACTION ((92-U-235(G,F),,SIG)/(92-U-238(G,F),,SIG)) L022200200003 STATUS (TABLE) Data taken from tab. 2 of the reference L022200200004 ERR-ANALYS (ERR-T) Total uncertainties (Info from author L022200200005 Krishichayan) In photofission cross-section ratio L022200200006 measurements most systematic uncertainties cancel. L022200200007 (ERR-1) Systematic uncertainty in mass of the L022200200008 reference foils L022200200009 ENDBIB 7 0 L022200200010 COMMON 1 3 L022200200011 ERR-1 L022200200012 PER-CENT L022200200013 1. L022200200014 ENDCOMMON 3 0 L022200200015 DATA 3 37 L022200200016 EN DATA ERR-T L022200200017 MEV NO-DIM NO-DIM L022200200018 8.98 1.713 0.074 L022200200019 9.17 1.765 0.072 L022200200020 9.38 1.924 0.077 L022200200021 9.54 1.788 0.072 L022200200022 9.80 1.918 0.071 L022200200023 9.97 1.832 0.068 L022200200024 10.18 1.951 0.071 L022200200025 10.36 1.829 0.067 L022200200026 10.58 1.905 0.070 L022200200027 10.78 1.956 0.070 L022200200028 10.96 1.972 0.072 L022200200029 11.18 2.178 0.075 L022200200030 11.38 2.105 0.074 L022200200031 11.57 2.433 0.087 L022200200032 11.79 2.508 0.084 L022200200033 11.95 2.846 0.095 L022200200034 12.17 2.786 0.090 L022200200035 12.36 2.992 0.096 L022200200036 12.58 2.737 0.083 L022200200037 12.77 2.774 0.079 L022200200038 12.95 2.610 0.083 L022200200039 13.17 2.420 0.078 L022200200040 13.38 2.370 0.075 L022200200041 13.56 2.251 0.053 L022200200042 13.77 2.145 0.066 L022200200043 13.94 2.118 0.066 L022200200044 14.18 2.024 0.061 L022200200045 14.37 2.029 0.061 L022200200046 14.58 1.922 0.059 L022200200047 14.77 2.039 0.062 L022200200048 14.98 1.977 0.060 L022200200049 15.18 1.979 0.061 L022200200050 15.57 1.856 0.060 L022200200051 15.76 1.852 0.060 L022200200052 16.16 1.799 0.059 L022200200053 16.35 1.867 0.055 L022200200054 16.55 1.734 0.060 L022200200055 ENDDATA 39 0 L022200200056 ENDSUBENT 55 0 L022200299999 ENDENTRY 2 0 L022299999999