光子计数成像探测器作为探测微弱光的重要手段, 由微通道板, 解码阳极以及后续的读出电路组成, 其中解码阳极的性能直接影响着探测器的成像质量。 作为一种电荷分割型阳极, Vernier阳极利用周期性的正弦电极区域替代了楔条形阳极(WSA)的线性电极, 可获得高的成像分辨率和大的电极活动区域。 根据Vernier阳极的设计原理对Vernier阳极进行了仿真和设计, 首先, 介绍了矢量形式的阳极解码, 确定了阳极设计参量为阳极周期长度, 电极振幅及电极波长; 其次, 分析了各阳极设计参量对探测器成像的影响, 利用Labview软件分别模拟了电子云, Vernier阳极板以及其相互作用成像情况, 确定了Vernier阳极周期长度与粗调波长之间的关系以及设计参数一定时, 成像达到最佳的电子云大小, 依照模拟结果和实际的加工条件, 设计和制备了周期为891 μm, 绝缘沟道为25 μm, 振幅为50 μm, 粗调数为5的九路Vernier阳极。

Based-MCP position-sensitive anode photon-counting imaging detector is good at detecting extremely faint light, which includes micro-channel plate (MCP), position-sensitive anode and readout, and the performances of these detectors are mainly decided by the position-sensitive anode. As a charge division anode, Vernier anode using cyclically varying electrode areas which replaces the linearly varying electrodes of wedge-strip anode can get better resolution and greater electrode dynamic range. Simulation and design of the Vernier anode based on Vernier’s decode principle are given here. Firstly, we introduce the decode and design principle of Vernier anode with nine electrodes in vector way, and get the design parameters which are the pitch, amplitude and the coarse wavelength of electrode. Secondly, we analyze the effect of every design parameters to the imaging of the detector. We simulate the electron cloud, the Vernier anode and the detector imaging using Labview software and get the relationship between the pitch and the coarse wavelength of the anode. Simultaneously, we get the corresponding electron cloud for the designing parameters. Based on the result of the simulation and the practical machining demand, a nine electrodes Vernier anode was designed and fabricated which has a pitch of 891 μm, insulation width of 25 μm, amplitude of 50 μm, coarse pixel numbers of 5.