本文提出了一种基于电荷电容分割位置分辨原理的光子位置读出阳极, 能够大幅提高该类探测器的空间分辨率和光子计数率。首先, 介绍了影响现有光子计数成像探测器成像性能的关键因素, 分析了采用电容分割位置分辨方法的优势; 其次, 对电荷电容分割原理展开了理论推导, 分析了光子位置与阳极读出信号变化的空间位置的相关性; 再次, 在理论推导的基础上, 分析了电容分割读出阳极相关物理参数对其空间位置分辨能力的影响; 然后, 提出了电容分割位置分辨阳极的优化设计原则, 并设计了一种新型的基于电容分割的二维光子位置读出阳极。最后, 利用有限元仿真工具COMSOL建立了该电容阳极的模型, 进行了位置分辨原理仿真, 并评估了空间分辨的准确性。仿真结果表明: 阳极的位置分辨误差小于50 μm, 中心区域的位置分辨误差小于5 μm, 阳极的位置分辨性能优良。

This paper proposes a new position-resolving readout anode based on charge capacitance-division, which can improve the spatial resolution and photon counting rate of its detector. Firstly, the key factors affecting the imaging performance of existing photon-counting imaging detectors are introduced and the advantages of using capacitance-division readout anodes are analyzed. Secondly, the principle of charge capacitance-division is theoretically deduced and the relation between photon position and detector signal output is analyzed. Then, based on the theoretical deduction, the impact of a capacitance-division anode′s physical parameters on the detector′s performance is analyzed. After that, the optimized design principle for a capacitance-division position-resolved anode is proposed. A novel readout anode based on charge capacitance-division for a photon counting detector is designed. Finally, by using the finite element simulation tool COMSOL, a model for that readout anode is established, which is used to simulate the process of position-sensitivity and its accuracy. The simulation results show that the position-resolution performance of the new readout anode with the optimized design is better than 50 μm in most areas.