中子检测爆炸物的MCNP模拟

MCNP simulation of neutron detecting explosive

利用中子发生器作为中子源进行了爆炸物检测方法的研究.物理模型采用点中子源,用三硝基甲苯(TNT)做模拟物,探测器为阵列式.用蒙特-卡罗方法模拟被中子辐照后N,C和O 3种元素,采用透射法和反射法进行了检测.根据改变N,C和O元素产生的特征γ射线计数,确定出最佳检测方法.结果表明:在爆炸物检测中,反射法得到的γ射线计数多,反射法优于透射法;用反射法检测爆炸物时,探测器距离中子源为15 cm时,探测效果最佳.

Study of detecting method of explosive materials has been done by using neutron generator as neutron source. A point neutron source was employed in the physical model. Trinitrotoluene （TNT） was employed as simulacrum. Detectors were arrayed in sequence. After N,C, O being irradiated, detecting results of reflection method and transmission method were simulated by Monte-Cardo method.According to the numbers of γ rays generated by N, C, 0 irradiated by neutrons, it＇s sure that the number of γ rays detected by reflection method was larger than that by transmission method. Thus,the reflection method is better than the transmission method in the detecting of explosive materials. Meanwhile, the efficiency of detection using reflection method was the best when the distance between source and detectors was 15 cm.