微通道板增益对光子计数探测器成像性能影响

摘要

微通道板作为二维位置灵敏阳极光子计数探测器中的电子倍增器件，其增益特性直接影响探测器的成像性能。搭建了系统测试平台，测量了微通道板的增益随电压变化曲线，并获得了3块微通道板叠加后的脉冲高度分布曲线。根据测试结果以及脉冲高度分布曲线的能量分辨率与探测器增益的均匀性之间的物理关系，选择合适电压值和增益对探测器的性能进行优化，探测器分辨率由3．56 lp/m m提高到4．49 lp/m m ，获得了清晰图像，为探测器的研制提供了技术支持。%Microchannel plate as an electron multiplier plays an important role in the two-dimen-sion position sensitive anode of the photon counting imaging detector .Its gain as one of the im-portant parameters has effect on imaging performance . Hence the microchannel plate's gain changing with volt was measured with a systematic testing platform ,and the pulse height dis-tribution of the photon counting detector was also obtained .According to the test results and the relationship between the pulse height distribution curve and energy resolution ,the appro-priate gain and volt were selected to optimize the performance of the detector .The resolution of detector increased from 3 .56 lp/mm to 4 .49 lp/mm and a clear image was got ,providing technical support for the development of the detector .