ENTRY 31617 20080720 31293161700000001 SUBENT 31617001 20080720 31293161700100001 BIB 12 50 3161700100002 TITLE Cross-section measurement for the 10B(n,alpha)7Li 3161700100003 reaction at 4.0 and 5.0MeV 3161700100004 AUTHOR (Guohui Zhang,Li'an Guo,Rongtai Cao,Jiaguo Zhang, 3161700100005 Jinxiang Chen) 3161700100006 INSTITUTE (3CPRBJG) 3161700100007 REFERENCE (J,ARI,66,1427,2008) 3161700100008 FACILITY (VDG,3CPRBJG)Experiments were performed at the 4.5MV 3161700100009 Van de Graaff accelerator of Peking University 3161700100010 DETECTOR (IOCH)A gridded ionization chamber (GIC) was used as 3161700100011 the charged particle detector. It has the advantages 3161700100012 of high detection efficiency (close to 100%), large 3161700100013 detection solid angle (almost 2Pi), the ability of 3161700100014 particle energy and direction determination and the 3161700100015 potential of discrimination of different particles. 3161700100016 (BF3)A BF3 long counter was used as a neutron flux 3161700100017 monitor. 3161700100018 SAMPLE A 10B sample and a 238U foil were set back-to-back 3161700100019 at the common cathode. The 10B sample was evaporated 3161700100020 on a tantalum backing 4.8 cm in diameter and 50 mm 3161700100021 in thickness. The abundance of the 10B isotope was 3161700100022 94.0%. The mass of the 10B sample was 514 mu-g, and 3161700100023 the thickness was 34.7 mu-g/cm2. The mass and the 3161700100024 diameter of the 238U sample were 7.85+-0.10 mg and 3161700100025 4.50 cm, and the abundance of the 238U isotope was 3161700100026 99.999%. 3161700100027 INC-SOURCE (D-D)Neutrons were produced through the D(d,n)3He 3161700100028 reaction with a deuterium gas target. The length of 3161700100029 the gas cell was 2.0 cm and the pressure of the 3161700100030 deuterium gas was 3.0-2.87 atm with a molybdenum 3161700100031 foil window 5 mm in thickness separated from the 3161700100032 vacuum tube. The energies of the deuteron beam 3161700100033 before enter the foil were 1.77 and 2.44 MeV, and 3161700100034 the neutron energies were 4.0 and 5.0 MeV, with 3161700100035 energy spreads 0.22 and 0.16 MeV, respectively. The 3161700100036 estimated neutron fluxes on the sample were 2.1x10**5 3161700100037 and 2.5x10**5 n/s/cm2 for the above-mentioned two 3161700100038 neutron energy measurements. 3161700100039 ERR-ANALYS (ERR-T) The main sources of error of the cross-section 3161700100040 value are: 3161700100041 (ERR-1) uncertainty in background subtraction 3161700100042 (ERR-2) uncertainty in the 238U fission cross-section 3161700100043 (ERR-3) uncertainty in the 238U fission count 3161700100044 (ERR-4)uncertainty in the atom number of the 10B sample3161700100045 (ERR-5) uncertainty in the atom number of the 3161700100046 238U sample 3161700100047 Total error is about 8%. 3161700100048 MONITOR (92-U-238(N,F),,SIG) data were taken from ENDF/B-VI.8 3161700100049 STATUS (TABLE) from the abstract of ref. 3161700100050 (APRVD) Entry approved by Dr. Guohui Zhang 3161700100051 HISTORY (20080720C) SD, LV. 3161700100052 ENDBIB 50 0 3161700100053 COMMON 5 3 3161700100054 ERR-1 ERR-2 ERR-3 ERR-4 ERR-5 3161700100055 PER-CENT PER-CENT PER-CENT PER-CENT PER-CENT 3161700100056 6.5 2.5 2.5 2.0 1.3 3161700100057 ENDCOMMON 3 0 3161700100058 ENDSUBENT 57 0 3161700199999 SUBENT 31617002 20080720 31293161700200001 BIB 1 1 3161700200002 REACTION (5-B-10(N,A)3-LI-7,,SIG) 3161700200003 ENDBIB 1 0 3161700200004 NOCOMMON 0 0 3161700200005 DATA 4 2 3161700200006 EN DATA ERR-T MONIT 3161700200007 MEV MB MB MB 3161700200008 4.0 211. 17. 548.1 3161700200009 5.0 169. 14. 540.5 3161700200010 ENDDATA 4 0 3161700200011 ENDSUBENT 10 0 3161700299999 ENDENTRY 2 0 3161799999999