增强光中子成像空间分辨率的方法研究

The Method Research of Enhancing the Spatial Resolution of Photoneutron Imaging

X射线和中子联合成像能够极大的提升针对不同种类违禁材料的鉴别能力。光中子源具有中子产额高,系统稳定性好,既是X射线源又是中子源的优点,其不足之处在于中子探测会受到X射线脉冲的干扰,而为了避免这种干扰采用慢化中子延时错开X射线脉冲的解决办法又将带来新的问题,即中子探测空间分辨率的恶化。本文提出了一种新颖的探测慢化后光中子的方法,能够极大地提升光中子探测的空间分辨率,并设计了一套光中子成像原型系统,通过模拟手段评估了系统的各项参数性能,获得了理想的模拟成像结果,验证了方法的可行性。

Combining both X- ray imaging and neutron imaging can significantly enhance the identification ability of Security- Check against contraband. Photoneutron source is an ideal choice for X- ray/neutron combined imaging because of its high neutron yield,good system stability and simplicity. Its shortcoming lies on the interference of X- ray pulse with neutron detection. To eliminate such kind of interference we have to moderate photoneutron to delay the neutron detecting time,which would cause another problem of spatial resolution deterioration. This article proposes a method of detecting moderated neutron without significant spatial resolution lose,meanwhile a system prototype has been designed for simulation work. MCNP is used to evaluate the performance of the system,and imaging- simulation results indicate the feasibility of the proposed method.