美国国家点火装置中低温定位器产生的背景中子通量密度的计算

Calculation of Background Neutrons Flux Caused by Cryogenic Target Positioner in National Ignition Facility

W.C.Mead等人[1]对美国国家点火装置(NIF)内的氘氚燃料反应产生的信号中子与低温定位器(CTP)、靶室壁反应产生的背景中子和背景光子的通量密度进行了计算。论文对同一系统进行再次研究,得到与W.C.Mead不同的结论。论文对W.C.Mead等人的研究进行勘误和拓展,使用MCNP对NIF中CTP和靶室壁对背景中子和背景光子的产生情况进行了计算和分析。通过计算在靶室内不同半径不同角度上的背景中子通量密度,确定了在靶室内最佳信噪比的角度,同时对探测器布置在靶室内的位置提出了建议。并且在W.C.Mead等人的研究基础上,改变CTP在靶室中的位置,计算并对比了CTP在靶室内不同位置上,所产生的背景中子和背景光子通量密度。

W. C. Mead et al. have calculated the background neutrons and gamma Time - of- Flight（TOF） spectra which are caused by Cryogenic Target Positioner （CTP） and chamber in National Ignition Facility （NIF）. The same system is studied again and different conclusion is reached in this paper. Hence, we correct and improve their study. The MCNP Monte Carlo code is used to calculate the neutron TOF spectra in NIF. Background neutron and gamma TOF spectra at different radius and different degree in chamber are calculated and compared to locate the angle of highest ratio of signal to background. To make the further improvement, the position of CTP has been altered to see its influence to the background neutron and gamma TOF spectra.