用金活化法测定加速器中子源中子注量及MCNP4C修正

在四川大学720所2.5MeV静电质子加速器上,由核反应7Li(p,n)7Be,T(p,n)3He产生中子,对中国工程物理研究院研制的新型中子探测器进行效率刻度实验中,需要知道探测器位置处的中子绝对注量,为此我们测量了0.165、0.352、0.576、1.400MeV四个能点的中子注量。测量方法采用的是金活化法,在实验测量中,由靶头材料、冷却水层和样品的包层材料等引起的多次散射效应及中子在样品中的自屏蔽效应等均对实验结果产生影响。这些因素在实验中不可避免,也难以通过实验方法扣除,因此用Monte Carlo程序MCNP4C对上述效应进行了修正计算。

The Measurement of Neutron Flux Using 197Au Neutron Activation from Static Accelerator

We have measured neutron flux at four energy point such as 0.165,0.352,0.576.1.400MeV usung the ~(197) Au activation technique from a 2.5 MeV electrostatic accelerator of Sichuan University,reaction of ~7 Li(p,n) ~7 Be and T(p,n) ~3 He was used for neutron sources.While they calibrated the efficiency of new detector for engineering and physics academe in China.The measurement have used ~(197)Au activation technique because the purity of ~(197) Au is higher and its cross section is standard and γ emitted from 198Au can be measured accurately.The experimental data were also corrected for multiple scattering and self-shielding effects with MCNP4C code.