ENTRY 32827 20230905 3282700000001 SUBENT 32827001 20230905 20240316 3282700100001 BIB 12 40 3282700100002 TITLE Measurement of the absolute value of thermal neutron 3282700100003 fission cross section at 235U 3282700100004 AUTHOR (Ye Chuntang,Sun Hancheng,Liu Huichang) 3282700100005 INSTITUTE (3CPRAEP) 3282700100006 REFERENCE (J,CST,6,349,1964) 3282700100007 INC-SOURCE (REAC) Using a crystal neutron spectrometer, the 3282700100008 neutron beam E=0.0253 eV was selected from heavy-water 3282700100009 reactor. NaCl (200) crystal was used as the 3282700100010 monochromator for the spectrometer.Between the 3282700100011 NaCl(200) monochromator and the measured sample a 3282700100012 mechanical monochromator was inserted in order to cut 3282700100013 off the neutrons with high energy. The high energy 3282700100014 neutron was less than 1%. 3282700100015 SAMPLE Nuclear emulsion of U was made of U3O8 powder. 3282700100016 Impurity content was less than 0.4%. The abundance of 3282700100017 235U was 20.2%(1+-0.1%). The sample was made into 3282700100018 uranyl nitrate (UO2(NO3)2) and added to the liquid 3282700100019 emulsion in its aqueous solution. Nuclear emulsion of 3282700100020 B was made of boric acid. 3282700100021 DETECTOR (TRD) Nuclear emulsion 3282700100022 METHOD 4 pieces of nuclear emulsions were used. The 1st and 3282700100023 4th were B, the 2nd and 3rd were U. The 1st and 2nd 3282700100024 were separated by Al foil in thickness of 100 um. The 3282700100025 3rd and 4th were the same. The irradiation time was 8 3282700100026 hours. 3282700100027 MONITOR (5-B-0(N,A),,SIG) 3282700100028 ERR-ANALYS (ERR-T) Total Uncertainty 3.81% 3282700100029 (ERR-S) Counting statistics 3282700100030 (ERR-1) Isotopic abundance of 235U 3282700100031 (ERR-2) Surface density of U 3282700100032 (ERR-3) Surface density of B 3282700100033 (ERR-4) Neutron beam and nonuniformity of emulsions 3282700100034 (ERR-5) Energy resolution of instrument, diffraction 3282700100035 neutron, multiple scattering, self-absorption, track 3282700100036 leakage and so on. 3282700100037 (MONIT-ERR)Thermal neutron absorption Cross Section 3282700100038 of B 3282700100039 STATUS (TABLE) Data were obtained from text of p.353 in 3282700100040 At.En.Sci.Technol.,6,349,1964 3282700100041 HISTORY (20230905C) Compiled by Xi Tao (CNDC) 3282700100042 ENDBIB 40 0 3282700100043 COMMON 6 3 3282700100044 ERR-S ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 3282700100045 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 3282700100046 0.53 1.00 0.32 0.30 0.50 0.503282700100047 ENDCOMMON 3 0 3282700100048 ENDSUBENT 47 0 3282700199999 SUBENT 32827002 20230905 20240316 3282700200001 BIB 1 1 3282700200002 REACTION (92-U-235(N,F),,SIG) 3282700200003 ENDBIB 1 0 3282700200004 NOCOMMON 0 0 3282700200005 DATA 5 1 3282700200006 EN DATA ERR-T MONIT MONIT-ERR 3282700200007 EV B B B PER-CENT 3282700200008 0.0253 582. 9. 764. 0.66 3282700200009 ENDDATA 3 0 3282700200010 ENDSUBENT 9 0 3282700299999 ENDENTRY 2 0 3282799999999