微通道板(Microchannel-plate, MCP)防离子反馈膜是负电子亲和势光电阴极微光像增强器的特有标志, 其主要作用是有效阻止反馈正离子轰击阴极以提高器件工作寿命。微通道板防离子反馈膜的厚度决定了其对电子透过、离子阻挡能力的大小, 电子透过能力直接影响图像的对比度和信噪比。根据微通道板防离子反馈膜阈值电压定义和测试原理, 对微通道板不同厚度防离子反馈膜、不同工作电压条件下的阈值电压特性进行了测试研究。结果表明: 防离子反馈膜的阈值电压随着膜层厚度的增加而增加, 两者之间遵循正比的线性关系: Y=398X+50; 在微通道板线性工作电压范围内, 防离子反馈膜的阈值电压随微通道板工作电压的增加而降低, 两者之间遵循反比关系。该研究对提高微通道板在负电子亲和势光电阴极微光像增强器中的使用性能具有重要意义。

Ion barrier film of Micro-channel Plate(MCP) is one of unique features of low-light-level(LLL)image intensifier with negative electron affinity. Its main function is to effectively prevent positive ions from bombarding cathode to improve working life of the device. Thickness of ionizing membrane of MCP determines size of electron permeation and ion blocking ability, and electron permeability directly affects contrast and signal to noise ratio(SNR) of the image. According to threshold voltage definition and test principle of ion barrier film of MCP, optimal thickness of ion barrier film is determined through lots of experiments. Results show that threshold voltage of ion barrier film increased linearly with increase of film thickness, linear relationship Y=398X+50 is proportional between two sides. Threshold voltage of ion barrier film decreased linearly with the increase of MCP operating voltage, showing an inverse proportion. This study is of great significance to improve performance of MCP in LLL image intensifier with negative electron affinity photonic cathode photoluminescence enhancers.