基于Si-PM阵列的辐射作用位置定位方法研究

Research on location method of radiation action based on Si-PM array

在辐射成像中准确估计射线与探测器相互作用的空间位置是保障成像质量的关键步骤。为进一步提升辐射作用事件的定位效果,有效抑制重心法在辐射事件作用位置靠近探测器边缘时造成的定位偏移,针对Si-PM阵列构成的位置灵敏探测系统建立了基于响应函数的定位算法。搭建了基于CsI阵列与Si-PM阵列构成的位置灵敏探测器和基于ASIC的电子学读出系统,使用等效电阻网络简化了Si-PM阵列的输出信号数量,通过实验获得了辐射事件在Si-PM阵列上的响应函数。实验结果表明,在同一条件下使用响应函数法在最边缘像素散点的FWHM仅为使用重心法获得FWHM的46.2%,与中央像素散点的FWHM相当,基于响应函数的辐射事件方法定位效果明显优于传统重心法的定位效果,可有效克服重心法的边缘效应。

Accurately estimating the spatial position of the interaction between the ray and the detector in radiation imaging is a key step to ensure the imaging quality.To further improve the position effect of radiation events and effectively suppress the position shift caused by the center of gravity method when radiation events are close to the edge of the detector,a response function-based position algorithm is established for the position-sensitive detection system composed of Si-PM arrays.A position-sensitive detector based on CsI array and Si-PM array and an ASIC-based electronic readout system were built,and the equivalent resistance network was used to simplify the number of output signals of Si-PM array,then the response functions of radiation events on Si-PM arrays were obtained experimentally.The experimental results show that under the same conditions,the FWHM of the scatter points of the most edge pixels using the response function method is only 46.2%of the FWHM obtained by using the center of gravity method,which is comparable to the FWHM of the scatter points of the central pixels,the localization effect of the radiation event method based on the response function is obviously better than that of the traditional center of gravity method,which can effectively overcome the edge effect of the center of gravity method.