ENTRY 32806 20210103 32003280600000001 SUBENT 32806001 20210103 32003280600100001 BIB 16 75 3280600100002 TITLE Measurement of 232Th neutron capture cross-sections 3280600100003 in the energy range of 2.0-5.0 MeV by using the 3280600100004 neutron activation technique 3280600100005 AUTHOR (Su Shen,Zhiling Yuan,Xiaobing Luo) 3280600100006 INSTITUTE (3CPRSIU) 3280600100007 REFERENCE (J,NIM/B,476,59,2020) 3280600100008 #doi:10.1016/j.nimb.2020.04.028 3280600100009 FACILITY (VDGT,3CPRSIU) 2 x 3 MV tandem accelerator 3280600100010 INC-SOURCE (P-T) Proton beam energy is 5.2 MeV. The proton beam 3280600100011 current was close to 35 uA and focused to bombard 3280600100012 solid tritium-titanium (T-Ti) target. The T-Ti target 3280600100013 has a thickness of 1.833 mg/cm2 and the atom ratio of 3280600100014 T to Ti is 1.84. Tantalum foil is behind the T-Ti 3280600100015 target which could stop the proton beam. At the end 3280600100016 of the target, a continuous cooling water flow with a 3280600100017 thickness of 4 mm was used to avoid local overheating. 3280600100018 SAMPLE Four disc-shaped samples with a diameter of 20 mm and 3280600100019 15 mm were made of ThO2 powder with a purity of more 3280600100020 than 99.9%, the area of sample 1 is 3.142 cm2 and the 3280600100021 area of all other sample is 1.767 cm2. The masses of 3280600100022 the four samples are 1.501 g, 1.233 g, 1.199 g and 3280600100023 1.288 g, which the mass thickness(tm) of samples are 3280600100024 0.478 g/cm2,0.698 g/cm2, 0.679 g/cm2 and 0.729 g/cm2. 3280600100025 These ThO2 samples were initially sandwiched between 3280600100026 two Au foils and then covered with 0.3 mm thick 3280600100027 cadmium. The Au foils (same diameter with thorium 3280600100028 samples and 0.1 mm thickness) were used to determine 3280600100029 the average neutron flux by 197Au(n,g)198Au reaction. 3280600100030 Meanwhile, the Cd box with high thermal neutron 3280600100031 capture cross-section was used for eliminating the 3280600100032 impact of scattered slow-thermal neutrons. The first 3280600100033 three samples were installed at 3.5 cm from the 3280600100034 center of the T-Ti target and at 0, 45 and 90 deg 3280600100035 angles to the proton beam, respectively. The last one 3280600100036 was mounted at 690 cm and 90 deg angle, which was 3280600100037 used to determine the contribution of the background 3280600100038 neutron in whole hall. 3280600100039 METHOD (ACTIV,GSPEC) The irradiation lasted for 6 h. The Au 3280600100040 foils were cooled for 2-3 h then placed into detector 3280600100041 to get gamma-ray spectra to further calculate the 3280600100042 average neutron fluence. The irradiated targets of Th 3280600100043 were cooled more time (1-2 days) and detected enough 3280600100044 time for getting as many statistics as possible. 3280600100045 DETECTOR (HPGE) The gamma-ray spectra of these irradiated 3280600100046 samples were detected with a low-background coaxial 3280600100047 high-purity germanium detector (GEM30P4-76, ORTEC). 3280600100048 The detector has a relative efficiency of 30% and an 3280600100049 energy resolution of 850 eV FWHM at 122 KeV and 1.85 3280600100050 KeV FWHM at 1.33 MeV. 3280600100051 (BF3) The neutron flux fluctuation was monitored with 3280600100052 a BF3 long counter that was placed at an another 45 3280600100053 deg angle and 481 cm from the target. 3280600100054 MONITOR (79-AU-197(N,G)79-AU-198,,SIG) 3280600100055 DECAY-MON (79-AU-198-G,2.693D,DG,411.8,0.9562) 3280600100056 MONIT-REF (,,3,ENDF/B-VIII.0,7925,2018) 3280600100057 CORRECTION The total correction factors of this neutron 3280600100058 irradiation experiment mainly involved four parts: 3280600100059 the multiple scattering neutron factor(Fs), the flux 3280600100060 attenuation factor(Fa), the gamma-ray self-absorption 3280600100061 factor(Fg) and the neutron flux fluctuation 3280600100062 factor(Ff). 3280600100063 F=(Fs*Fa*Fg*Ff)Th/(Fs*Fa*Fg*Ff)Au 3280600100064 En FsTh/FsAu FaTh/FaAu FgTh/FgAu FfTh/FfAu F 3280600100065 4.36+-0.06 1.138 1.0152 1.102 1.001 1.2733280600100066 3.52+-0.41 1.098 1.0433 1.151 1.001 1.3193280600100067 2.06+-0.34 1.053 1.0478 1.147 1.001 1.2663280600100068 ERR-ANALYS (ERR-T) Total uncertainty 3.2%-4.6% 3280600100069 (ERR-S,1.0,2.0) Counting statistics 1.0%-2.0% 3280600100070 (ERR-1) Detection efficiency 1.5% 3280600100071 (ERR-2) Decay scheme 1.5% 3280600100072 (ERR-3,,1.0) The samples weighing less than 1.0% 3280600100073 (MONIT-ERR,1.7,4.0) Reactions cross-section of Au 3280600100074 1.7%-4.0% 3280600100075 STATUS (TABLE) TABLE 4 of Nucl.Instr.Meth.B 476,59,2020. 3280600100076 HISTORY (20210103C) Compiled by Xi Tao (CNDC) 3280600100077 ENDBIB 75 0 3280600100078 COMMON 2 3 3280600100079 ERR-1 ERR-2 3280600100080 PER-CENT PER-CENT 3280600100081 1.5 1.5 3280600100082 ENDCOMMON 3 0 3280600100083 ENDSUBENT 82 0 3280600199999 SUBENT 32806002 20210103 32003280600200001 BIB 3 3 3280600200002 REACTION (90-TH-232(N,G)90-TH-233,,SIG) 3280600200003 DECAY-DATA (91-PA-233,26.975D,DG,311.9,0.384) 3280600200004 RAD-DET (91-PA-233,DG) 3280600200005 ENDBIB 3 0 3280600200006 NOCOMMON 0 0 3280600200007 DATA 4 3 3280600200008 EN EN-ERR DATA ERR-T 3280600200009 MEV MEV MB MB 3280600200010 2.06 0.34 52.76 1.69 3280600200011 3.52 0.41 8.03 0.28 3280600200012 4.36 0.06 2.19 0.11 3280600200013 ENDDATA 5 0 3280600200014 ENDSUBENT 13 0 3280600299999 ENDENTRY 2 0 3280699999999