非理想背光照相对靶壳阿贝尔密度反演的影响

摘要

建立了背光照相的模拟手段,研究了记录屏像素尺寸、背光强度分布、背光光谱非单色、针孔弥散及针孔形状对惯性约束聚变中常用塑料球壳的阿贝尔密度反演的影响.结果表明:较大的记录屏像素尺寸会掩盖密度分布的细节；高斯型的背光空间分布会使密度分布低于真实值,可能导致非物理的负密度分布；采用Mo的L带谱线作为背光源也会导致反演密度偏离真实值；当壳层厚度小于针孔尺寸时,针孔弥散效应会显著降低峰值密度,利用维纳滤波法处理背光图像后密度反演的结果得到明显改善；相同针孔面积条件下,椭圆形针孔给出的峰值密度要低于圆形针孔的结果.%With a simulation method for backlighter radiography established in the paper, we study the effect of many non-ideal factors on the Abel density inversion of plastic target shell frequently used in inertial confinement fusion. These non-ideal factors include the pixel size of the recording screen, the spatial distribution of backlit intensity, the non-monochromatic spectra of backlighter source, the diffusion of pinholes and the shape of pinholes. The details of the density profile can be covered up by large size of pixel; the Gaussian backlighter intensity can result in lower density relative to real density profile and unphysical negative density; the density shows a certain deviation from real profile if the L-band of Mo is used as the backlighter source; the peak density can be decreased significantly by the diffusion effect if the thickness of the shell is smaller than the size of the pin-hole, and the results can be improved if the Wiener filter is used to process the radiography. With the same area of pinholes, the peak density for the elliptical pinhole is smaller than that for the circular pinhole.