辐射成像系统中图像转换屏与物镜耦合的分析  

Analysis on coupling between scintillator and lens in radiographic imaging system

作　　者：宋顾周[1] 王奎禄[1] 马继明[1] 周鸣[1] 

机构地区：[1]西北核技术研究所,西安710024

出　　处：《强激光与粒子束》2012年第2期471-475,共5页High Power Laser and Particle Beams

基　　金：国家自然科学基金项目(10775112;61171013)

摘　　要：辐射成像系统中,射线沿闪烁体厚度方向产生的光经过镜头形成一个弥散的像。这通常是此类系统空间分辨的主要限制因素。建立了几何光学成像模型,描述了近心光路中此图像的空变特性。用点扩散函数均方根半径表征系统空间分辨性能,给出了图像点扩散函数均方根半径的表达式,其与闪烁体厚度、折射率、镜头相对孔径、成像倍率、射线入射点相对位置直接相关。将硅酸镥晶体3维发光强度分布与镜头进行耦合,分析了闪烁体发光强度分布对耦合的影响。采用点扩散函数均方根半径为最小的原则,建立了一个推导闪烁体相对于物镜放置在最佳位置的方法。In a radiographic imaging system, the created light along the thickness direction of the scintillator is focused by a lens to form a blurred image, which is a limiting factor for the spatial resolution of the imaging system. Geometric optics models have been developed to describe the imaging process. To parameterize the slSatial resolution, the standard deviation of the blurred image has been expressed by the parameters of the imaging system. A method is found to optimize the position of a thick scintilla- tor with respect to the object focal plane of the lens, in which the deviation of the blurred image will be minimized.

关 键 词：辐射成像 空间分辨 几何光学 图像转换屏 物镜 标准偏差 

分 类 号：TL503[核科学技术—核技术及应用] TN249[电子电信—物理电子学]