中子半影成像的散射中子对点扩展函数的影响

基于ICF中子半影成像分辨力的要求，利用蒙特卡罗方法，模拟了4种系统模型的点扩展函数，分析半影孔装置、靶室和中子束流通道的钢管、高密度内爆靶丸的散射中子对点扩展函数的影响；模拟了平面中子源在4种模型中的半影成像,并用维纳滤波方法重建，分析了散射中子对中子半影成像诊断的影响。模拟结果表明:半影孔装置、靶室等的散射中子不会造成点扩展函数的变形，仅仅增加本底，对诊断的影响可以忽略；高密度内爆靶丸的散射中子会造成点扩展函数的平滑，但对诊断的影响有限。

Effect of scattered neutrons on point spread function in neutron penumbral imaging

The point spread function (PSF) has been calculated by Monte Carlo method for neutron penumbral imaging in inertial confinement fusion experiments, and the impact of scattered neutrons in the aperture, the chamber and the pipe, and the high density target was analyzed. The neutron penumbral imaging for a planar neutron source was simulated and the image was reconstructed by Wiener method. According to the results, the scattered neutrons in the penumbral-aperture, the chamber and the pipe will only raise the background but not distort the PSF, thus their influence on diagnosis can be ignored. The scattered neutrons in the high density target can smooth the PSF, however, the effect on diagnosis is quite limited.