中子诱发TNT中轻核素反应的混合γ能谱模拟

Simulations to neutron-induced gamma ray spectra of light nuclides in TNT

用MCNP模拟了Am-Be中子源诱发土壤环境中爆炸物各组成核素形成的瞬发γ射线在NaI(Tl)和BGO探测器中的能谱,得到H、C、N、O核素特征峰计数随爆炸物质量的变化关系,研究了土壤湿度对γ能谱的影响。通过对中子诱发爆炸物的瞬发γ能谱分析,发现N、C核素特征γ射线全能峰计数之比能较好识别含水环境下的爆炸物。

There are several factors affecting the detection of explosive or landmine using neutron-induced reactions,such as the neutron source,detector,object and surroundings.In this paper,using a system of NaI（Tl） or BGO detectors and an Am-Be neutron source,prompt gamma ray spectra from nuclides in TNT of landmine in soil are simulated by MCNP.The counts of full energy characteristic peaks of gamma rays from hydrogen,carbon,nitrogen and oxygen in TNT are related to the explosive mass.Effects of the soil moisture on the gamma-ray spectrum are studied.The ratio of full energy peak counts from nitrogen to full energy peak counts from carbon is defined.A method to use the ratio to identify explosives under water environment is proposed.