ENTRY 32709 20130605 31603270900000001 SUBENT 32709001 20130605 31603270900100001 BIB 16 96 3270900100002 TITLE Determination of cross sections for the 238U(n,3n)236U 3270900100003 reaction induced by 14-MeV neutrons with accelerator 3270900100004 mass spectrometry 3270900100005 AUTHOR (Xianggao Wang,Shan Jiang,Ming He,Kejun Dong, 3270900100006 Caijing Xiao,Yueming Hu,Qubo You,Hongtao Chen, 3270900100007 Long Hou,Weixiang Yu,Xichao Ruan) 3270900100008 INSTITUTE (3CPRCPR) Guangxi University, Nanning, China 3270900100009 (3CPRAEP) 3270900100010 REFERENCE (J,PR/C,87,014612,2013) 3270900100011 #doi:10.1103/PhysRevC.87.014612 3270900100012 FACILITY 1(CCW,3CPRAEP) 600 kV Cockcroft-Walton accelerator for 3270900100013 sample irradiation 3270900100014 2(VDGT,3CPRAEP) HI-13 tandem accelerator for accelerator3270900100015 mass spectrometry. 3270900100016 SAMPLE The sample was made of 99.99% purity U3O8 powder with 3270900100017 a diameter of 5 mm, and sandwiched between two disks 3270900100018 made of thin Co foils. The high-purity (99.999%) Co 3270900100019 monitors had diameters of 5 mm and thicknesses of 0.2 3270900100020 mm. 3270900100021 DETECTOR 1(HPGE) A HPGe gamma-ray spectrometer consisting of an 3270900100022 ORTEC GEM35-PLU HPGe detector (sensitive volume 110 3270900100023 cm3), an ORTEC DESPEC-PLUS analyzer, and a PC 3270900100024 computer. The emission rates of 810.7953-keV gamma 3270900100025 rays from 59Co(n,2n)58Co reaction were measured with 3270900100026 this system. The system has an energy resolution of 3270900100027 1.83 keV and a relative efficiency of 47% (both are 3270900100028 for 1.33 MeV gamma ray). 3270900100029 (SIBAR) An Au-Si surface barrier detector was 3270900100030 installed at 155 degree with respect to the D beam 3270900100031 and a distance of 195 cm from the 3H-Ti target for 3270900100032 the detection of accompanying alpha particles. 3270900100033 2(SIBAR) An Au-Si surface barrier detector was used as 3270900100034 the energy detector for mass/charge discrimination. 3270900100035 (MCPLT) The secondary electrons induced by the 3270900100036 incoming ions at a 7 ug/cm2 carbon foil (with a 3270900100037 diameter of 30 mm) were reflected by an electrostatic 3270900100038 mirror, collected and multiplied by the MCPLT. 3270900100039 METHOD 1(ACTIV) Irradiation of the samples was carried out 3270900100040 and lasted 198 h with a neutron yield around 3E10 to 3270900100041 5E10 n/(4pi*s). 3270900100042 2(TOF) The TOF system consisted of a microchannel 3270900100043 plate (start detector) and a gold-silicon surface 3270900100044 barrier detector (stop detector). The two detectors 3270900100045 were separated by a flight path of 1.8 m. 3270900100046 (AMS) This facility is based on an HI-13 accelerator 3270900100047 equipped with a cesium sputter ion source. The 3270900100048 dedicated injector is composed of a 90 degree 3270900100049 spherical electrostatic analyzer (SESA), a 112 degree 3270900100050 double focusing analyzing magnet (DFMA) and some ion- 3270900100051 optical elements. The SESA has a curvature radius of 3270900100052 750 mm and maximum electric field strength of 4 kV/cm. 3270900100053 The DFMA has a bending radius of 800 mm and a maximum 3270900100054 magnetic field of 1.3 T. 3270900100055 MONITOR (27-CO-59(N,2N)27-CO-58,,SIG) 3270900100056 DECAY-MON (27-CO-58-G,70.82D,DG,810.7953,0.99450) 3270900100057 MONIT-REF (,A.Smith+,3,ENDF/B-VII.0,2725,2006) 3270900100058 INC-SOURCE (D-T) The thickness of the solid tritium-titanium 3270900100059 target used in the generator was 1.0 mg/cm2 and the 3270900100060 energy of incident D beam was 300 keV. 3270900100061 ERR-ANALYS (ERR-T) Total uncertainty is the combination of the 3270900100062 uncertainties in integral neutron flux, determined by 3270900100063 gamma-ray spectrometric measurement of the activated 3270900100064 monitor and the 236U/238U, determined by AMS. 3270900100065 (ERR-1,,0.1) The uncertainties of the accompanying 3270900100066 alpha particle counting statistics is less than 0.1%. 3270900100067 (ERR-2,,0.1) Uncertainty of weight Co sample. 3270900100068 (ERR-3,,0.1) Uncertainty of the composite correction 3270900100069 factor F of the activity. 3270900100070 (ERR-4,,0.1) Uncertainty of gamma ray branching ratio 3270900100071 of 58Co (810.7953 keV). 3270900100072 (ERR-5) The uncertainties of the HPGe efficiency 3270900100073 calibration is 1.2%. 3270900100074 (ERR-S) The uncertainty of gamma-ray peak counting 3270900100075 statistics is 0.3%. 3270900100076 (ERR-6) The uncertainty is come from the U236/U238 3270900100077 ratio measurement by AMS method. 3270900100078 (MONIT-ERR) The uncertainty in the cross-section of 3270900100079 59Co(n, 2n) is 1.0%. 3270900100080 (EN-ERR) Uncertainty of incident neutron energies is 3270900100081 the quadratic summation of the uncertainties caused 3270900100082 by the energy straggling of incident D in target and 3270900100083 the angle divergence from target to samples. 3270900100084 STATUS (TABLE) All measured reactions data and monitor 3270900100085 reaction data are taken from J,PR/C,87,014612,2013. 3270900100086 COMMENT The uncertainties in incident neutron energies are 3270900100087 included in neither the uncertainty of the neutron 3270900100088 flux nor the cross-section values in the experiment. 3270900100089 Since neither neutron source nor sample is a 3270900100090 geometrical "point", neutron energy dispersion is 3270900100091 inevitable in any experiment. Users of cross-section 3270900100092 values may therefore be aware of the uncertainty in 3270900100093 incident neutron energy. (Commented by author) 3270900100094 Xianggao Wang (2013-06-06): Uncertainties given in 3270900100095 TABLE V must be swapped. The total uncertainties are 3270900100096 correctly given in TABLE VI. 3270900100097 HISTORY (20130605C)Compiled by CHEN Guochang (CNDC) 3270900100098 ENDBIB 96 0 3270900100099 COMMON 3 3 3270900100100 ERR-5 ERR-S MONIT-ERR 3270900100101 PER-CENT PER-CENT PER-CENT 3270900100102 1.2 0.3 1.0 3270900100103 ENDCOMMON 3 0 3270900100104 ENDSUBENT 103 0 3270900199999 SUBENT 32709002 20130605 31603270900200001 BIB 1 1 3270900200002 REACTION (92-U-238(N,3N)92-U-236,,SIG) 3270900200003 ENDBIB 1 0 3270900200004 NOCOMMON 0 0 3270900200005 DATA 6 2 3270900200006 EN EN-ERR DATA ERR-T ERR-6 MONIT 3270900200007 MEV MEV MB MB PER-CENT MB 3270900200008 14.18 0.30 489.3 48.0 4.7 709.5 3270900200009 14.65 0.40 556.7 27.8 9.7 753.5 3270900200010 ENDDATA 4 0 3270900200011 ENDSUBENT 10 0 3270900299999 ENDENTRY 2 0 3270999999999