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~(175)Lu(n,2n)~(174m,g)Lu(n,2n)~(173)Lu反应在高能中子通量监测中具有重要作用,其产物的放射性活度通常用HPGe探测器测量,这就需要~(174m,g)Lu和173Lu的半衰期和γ射线发射率等衰变数据必须准确无误。在主要的评价核数据库中,只有ENDF/B 7.1和JEFF 3.1.1数据库给出了~(173)Lu和~(174)Lu的半衰期和γ射线的发射几率等衰变数据,其中~(173)Lu的γ射线发射几率ENDF/B 7.1库比JEFF 3.1.1库总体偏高,其他评价数据两个数据库非常一致。在中国原子能研究院的串列加速器上用20 Me V质子辐照金属Yb靶生产了含有~(173)Lu,~(174m,g)Lu的放射性溶液,用激光共振电离质谱(LRIMS)和热表面电离质谱(TIMS)两种同位素稀释法测定了该溶液中173Lu和174m,gLu核素浓度,然后制备测量源在HPGe探测器上进行了近7年的跟踪测量,发现~(173)Lu的半衰期为1.45 a,比目前评价的数据1.37 a高6.1%,636.1 ke Vγ射线发射几率的偏差最大,比ENDF/B 7.1的评价数据偏高7%。~(174g)Lu半衰期的测量结果 3.37 a,比评价数据3.31 a高约1.8%,174gLu 76.5 keV和1 241.8 ke Vγ射线的发射几率比ENDF/B 7.1的评价数据分别低1.87%和12.8%。
The reaction of Lu (n, 2n) ~ (173) with Lu (n, 2n) ~ (174m, g) plays an important role in the monitoring of high energy neutron flux. The radioactivity of its products is usually detected by HPGe This requires decay data of ~ (174m, g) Lu and 173Lu half-lives and gamma-ray emissivity to be accurate. Only the ENDF / B 7.1 and JEFF 3.1.1 databases give decay data for the half-lives of ~ (173) Lu and ~ (174) Lu and the γ-ray emission probabilities in the main evaluation nuclear database, where ~ (173) Lu γ-ray emission probabilityENDF / B 7.1 library JEFF 3.1.1 library overall high, the other evaluation data of the two databases are very consistent. A radioactive solution containing ~ (173) Lu, ~ (174m, g) Lu was produced by irradiating a metal Yb target with 20 MeV proton at a tandem accelerator at China Atomic Energy Research Institute. Laser induced ionization mass spectrometry (LRIMS) and thermal Surface isotope mass spectrometry (TIMS) two kinds of isotope dilution method was measured in the solution of 173Lu and 174m, gLu nuclide concentration, and then measuring the source of the HPGe detector for nearly 7 years of follow-up measurements found ~ (173) Lu The half-life is 1.45 a, which is 6.1% higher than the current estimate of 1.37 a. The maximum deviation from the 636.1 ke V γ-ray emission is 7% higher than the data from the ENDF / B 7.1 evaluation. The measured half-life of ~ (174g) Lu was 3.37 a, which was about 1.8% higher than the estimated data of 3.31 a. The emission probabilities of 174gLu 76.5 keV and 1 241.8 ke Vγ rays were 1.87% and 12.8% lower than those of ENDF / B 7.1, respectively.