Resolution- versus sensitivity-effective diameter in pinhole collimation: experimental verification.
Resolution- versus sensitivity-effective diameter in pinhole collimation: experimental verification.
复制标题
针孔准直中的分辨率与灵敏度有效直径：实验验证。
DOI：
10.1088/0031-9155/50/21/004
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Accorsi,R
中科院分区：
文献类型：
--
作者：
Metzler,SD;Accorsi,R
为了考虑光子穿透，用于计算针孔准直器的几何分辨率的公式使用有效直径d e而不是孔径的物理直径。然而，通常用于d e的表达式最初是为了在灵敏度计算中包括穿透而推导出来的。为了预测刀口针孔准直器的点扩散函数（PSF）的半高全宽（FWHM）分辨率，我们先前已经提出了分辨率有效直径dre的简单表达式。与d e的表达式不同，d re的表达式预测了对源极角（θ）的依赖性和非各向同性PSF。本文通过测量点扩散函数的半高宽，对新理论进行了验证。结果证实了理论预测：（a）d re提供了实验半高宽的最佳估计，它是θ和针孔平面方向的函数;（B）Paix的d e表达式倾向于高估半高宽;（c）Anger的表达式是一个更好的近似，但仍然不能预测对θ的依赖性;（d）半高宽随θ的减小而减小。即对于视场边缘处的源的分辨率提高。
To account for photon penetration, the formulae used to calculate the geometric resolution of a pinhole collimator use an effective diameter d e rather than the physical diameter of the aperture. The expressions commonly used for d e, however, were originally derived to include penetration in sensitivity calculations. To predict the full width at half maximum (FWHM) resolution of the point-spread function (PSF) of a knife-edge pinhole collimator, we have previously proposed simple expressions for a resolution-effective diameter d re. Unlike those for d e, expressions for d re predict both a dependence on the polar angle of the source (θ) and a non-isotropic PSF. In this paper, the new theory was tested by measuring experimentally the FWHM of the PSF. Results confirm the theoretical predictions that (a) d re provides the best estimates of the experimental FWHM as a function of θ and of the direction in the plane of the pinhole,(b) Paix's expression for d e tends to overestimate the FWHM,(c) Anger's is a better approximation, but still cannot predict the dependence on θ, and (d) the FWHM decreases with decreasing θ, ie resolution improves for sources at the edge of the field-of-view.