γ射线对含氢正比计数管中子能谱测量的影响  

Influence of gamma rays on measurement of neutrons spectra with spherical proportional counter of recoil protons

作　　者：赖财锋[1] 王新华[1] 刘荣[1] 杨小飞[1] 

机构地区：[1]中国工程物理研究院核物理与化学研究所,四川绵阳621900

出　　处：《强激光与粒子束》2014年第9期250-254,共5页High Power Laser and Particle Beams

摘　　要：通过蒙特卡罗模拟和实验测量相结合的方法,获得从50keV^10MeV区间γ射线在直径为30mm内充1.013 25MPa氢气的球形含氢正比计数管上的能量响应,结果显示,γ射线在该计数管中的能量沉积主要集中在100keV附近及以下。Am-Be中子源和137 Cs源的实验测量结果显示,强137 Cs源的γ射线会严重影响含氢正比计数管对Am-Be中子源100keV以下能谱的测量,这表明,裂变材料介质内的强γ射线同样会影响到介质内100keV以下中子能谱的测量。根据计数管对反冲质子和电子电离信号的收集特性,采用上升时间法甄别掉本底γ射线是可行的。The energy responses of gamma rays from 50 keV to 10 MeV of a spherical counter filled with 1MPa hydrogen and with a 30 mm diameter have been obtained by experimental measurement and Monte Carlo simulation.It shows that the energy deposited in the counter is focused near 100 keV and below.An experiment with Am-Be source and 137 Cs source indicates that intense gamma rays of the 137 Cs source have made great influence on the measurement of the neutrons spectra below 100 keV from Am-Be source.It can be concluded that the measurement of neutron spectra below 100 keV from fissionable materials would be affected by the intense gamma rays.According to the collective features of recoil protons and electrons ionization in the counter,it is feasible to discriminate the gamma rays from the neutrons by rise-time method.

关 键 词：含氢正比计数管 中子能谱 裂变材料 Γ射线 能量响应 (n γ)甄别 

分 类 号：O571.5[理学—粒子物理与原子核物理]