包装物对爆炸物中子检测的影响

文章概述了目前主要的爆炸物中子检测方法,介绍了用热中子俘获γ射线法（TNA法）检测爆炸物的原理,用模拟实验装置对模拟爆炸物进行了检测,得到了被测物的俘获γ射线能谱。实验装置采用d-D中子管产生2.5MeV的快中子,再经慢化之后得到热中子,并采用多个NaI探测器提高检测效率。着重对TNA法中不同外包装物材料以及多层复合外包装物材料对探测结果的影响进行了探索研究和结果分析,发现铜外壳对γ射线的屏蔽较大程度地降低了检出率,而例如聚四氟乙烯等塑料外壳也可能造成类似的影响。

Study on the Influence of Different Containers in Explosive Detection

This article summarized the current major neutron based explosive detective methods,introduced the principle of the thermal neutron capture γ-ray method（TNA）.The capture γ-ray spectrum of measured objects was obtained using an experimental device to detect simulated explosives.The experimental device used thermal neutron produced by moderation of 2.5MeV fast neutron yielded by d-D neutron tube,and a number of NaI detectors were used to improve detection efficiency.This article focused on the impact of different overpack materials and multi-layer composite overpack on detection results of TNA method.It is shown that copper shell will lower the detection rates by shielding a great degree of the γ-ray,and plastic shells such as polytetrafluoroethylene（PETF） may also cause the similar effect.