中子活化法测定~(232)Th裂变产物产额

采用中子活化法测量了~(232)Th的裂变产物及其累积产额。利用加速器T(d,n)~4He反应产生的14.9 MeV高注量中子长时间照射ThO_2样品,用高纯锗γ谱仪测量其特征γ谱,求得较长半衰期核素~(99)Mo、~(141)Ce、~(143)Ce、~(131)I、~(140)Ba等的裂变产额,实验结果的典型误差为4%。其中,利用MCNP程序对中子的多次散射效应和自屏蔽效应进行修正,同时考虑了中子注量波动及γ射线在样品中的自吸收影响。

Fission Product Yields Measurement of 232Th by Activation Technique

The cumulative yields of fission products of 232 Th were determined using activation technique.The ex-periment was performed using a multiple accelerator.The ThO2samples were irradiated for a long time by the neutrons that were produced via T(d,n)4He reaction.The characteristic γrays were detected by a HPGe de-tector and the yields of longer half -time fission products(99 Mo、141Ce、143Ce、131I、140Ba)were evaluated.The typical uncertainty of experimental results is 4%.The deflections which were caused by multiple scattering and self-shielding of the target and sample in the experiment were corrected with MCNP 5(Monte Carlo).Neutron-flux instability and sample self -absorption were also considered.