基于14 MeVμs脉冲中子发生器与NaI(Tl)和BGO闪烁探测器的爆炸物检测系统的研制

Study on the System of 14 MeV Neutron Generator-based Explosives Detection Using NaI(Tl) and BGO Detectors

介绍了利用14MeVμs脉冲中子发生器、NaI(Tl)和BGO闪烁探测器建立的爆炸物检测实验系统。研究了中子感生瞬发γ能谱的时间特性,分别测量了快中子的非弹性散射γ能谱和热中子辐射俘获γ能谱。使用了NaI(Tl)和BGO两种探测器测量γ能谱;NaI(Tl)探测器在测量14N的热中子辐射俘获γ10.835MeV时表现出了很好的性能,而BGO探测器则在测量12C和16O的快中子非弹性散射γ时得到了较好的结果。利用这两种探测器测量了22种样品,其中包括RDX、TNT、NQ3种炸药。根据NaI(Tl)和BGO测量到的中子感生瞬发γ能谱,在分析了1H、12C、14N、16O的元素含量之后,有效地实现了对炸药与普通物品的分辨。

a 14 μs MeV neutron pulse generator-based explosives detection system is introduced, which uses 100 mm×100 mm NaI(Tl) and 50 mm×50 mm BGO as γ detectors. 5 μs-width 14 MeV neutron pulses are produced by the neutron generator with the repetition frequency of 1, 5, 10 or 20 kHz, respectively. A 4 inch NaI(Tl) detector is used to detect the radiative capture γ , and a 2 inch BGO detector is used to detect the inelastic γ from inspected materials. 22 kinds of materials, including 3 kinds of explosives RDX, TNT and NQ are measured. The experimental results show that explosives can be discriminated from common materials correctly with the information of 14N, 1H and 16O concentrations, which are extracted based on the measured γ spectrum.