高分辨率CCD辐射探测器串扰校正

近年来出现的新型闪烁体与科学级CCD图像传感器耦合的高分辨辐射探测器，对提高Micro-CT等高分辨成像系统的空间分辨率、信噪比、图像质量等有重要意义，具有广泛的应用前景。但新型闪烁体如Gd₃Al₂Ga₃O₁₂等发光传输的各向同性特性，给μm尺寸的CCD像元带来了严重的串扰噪声，导致辐射探测器系统空间分辨率的实际值与理论值相差甚远。本文理论分析了高分辨率CCD辐射探测器串扰产生的物理机理，提出了利用蒙特卡罗EGSnrc仿真和Zemax光学仿真工具理论计算探测器系统像元间的串扰率函数（CTF），再以CTF为卷积核，通过Lucy-Richardson反卷积运算对实际投影数据进行串扰校正，用双丝型像质计进行验证实验。实验结果表明，本方法可有效校正探测器串扰噪声，对改善探测器系统的调制传递函数和提高空间分辨率等有明显的效果。

Crosstalk Correction for High-resolution CCD Radiation Detector

In recent years, high-resolution radiation detectors with direct coupling between new scintillators and CCD image sensors play an important role in improving the spatial resolution, detection efficiency, image quality and other performance indexes of Micro-CT and other high-resolution imaging systems. However, due to the micron pixel size of CCD and the isotropic luminescence and other characteristics of new scintillators such as Gd₃Al₂Ga₃O₁₂, it also brings serious crosstalk noise between the detector pixels, resulting in the difference between the actual and theoretical values of the spatial resolution of the radiation detector system. Firstly, the physical mechanism of crosstalk of high-resolution CCD radiation detector was systematically analyzed theoretically in this paper. Secondly, utilizing the tools such as Monte Carlo EGSnrc, Zemax and so on, the crosstalk rate function (CTF) was calculated theoretically. Then CTF was used for crosstalk correction of projected data. Finally, the image experiment of the dual-filament was implemented. It is illustrated that this method can effectively correct the crosstalk noise and improve the spatial resolution and modulation transfer function evidently for the high-resolution CCD radiation detector.