14.8 MeV中子诱发^(238)U裂变产物产额测量  

Measurement of fission product yields on ^(238)U induced by 14.8-MeV neutrons

作　　者：孙琦[1] 罗小兵[1] 李宛琼 汪超[1] 李子越 

机构地区：[1]四川大学原子核科学技术研究所辐射物理及技术教育部重点实验室,成都610064

出　　处：《核技术》2017年第7期12-17,共6页Nuclear Techniques

基　　金：中国工程物理研究院中子物理学重点实验室项目(No.2014BA06)资助~~

摘　　要：裂变产物产额作为裂变过程的一个重要参数,其准确测量对有关裂变的很多方面都有重要意义。为了准确测量中子诱发^(238)U裂变产物产额,利用中国工程物理研究院PD-300加速器上的T(d,n)4He反应,产生14.8MeV的中子,诱发^(238)U裂变。辐照过程中,通过金硅面垒半导体探测器监测中子通量的变化。使用Al片作为监测片计算整个照射过程中样品的平均中子通量。辐照结束后,利用高纯锗(High-Purity Germanium,HPGe)探测器测得裂变产物特征γ射线计数,计算得到裂变产物的产额,使用MCNPX软件对中子的多次散射和自屏蔽效应进行修正,并通过计算得到样品和监测片的自吸收修正、中子通量波动因子。得到了95Zr、127Sb、140Ba、147Nd、131I、103Ru等长半衰期产物的累积产额值,并将结果与以前的文献值做了比对,研究结果有助于^(238)U裂变产物产额的分析和评价。Background： The precise measurement of fission product yields is significant to many aspects of fission, because it＇s an important parameter in fission procedure. Purpose： The aim is to measure fission product yields of 238U induced by neutrons accurately. Methods： The T（d, n）4He reaction on the PD-300 accelerator of China Academy of Engineering Physics was used to produce 14.8-MeV neutrons. The neutron flux was monitored by Au（Si） surface barrier semiconductor detector during the irradiation. The average neutron flux in the whole process of irradiation was calculated by Al. After the irradiation, the sample was placed in front of a high purity germanium detector to measure the characteristic gamma rays of the fission products. Then cumulative yields were calculated through the counts. The Monte Carlo program MCNPX was used to estimate the effects of multiple scattering and self-shielding of neutrons. The corrections of self-absorption and the neutron flux fluctuation were also calculated. Results： The fission product yields for some long half-life radionuclide, i.e., 95Zr, 127Sb, 140Ba, 147Nd, 131I, 103Ru were determined. Conclusion： The results were compared with previous literature values, and they are helpful to the analysis and evaluation of 238U yield.

关 键 词：238U 裂变产额 DT加速器中子源 活化法 蒙特卡罗 

分 类 号：TL99[核科学技术—核技术及应用]