降低微通道板输入面电极反射率的技术途径

Technical solution on reducing reflectance of MCP inputsurface electrode

  • 摘要: 为了降低透明或半透明光电阴极的光子在微通道板输入面上引起的散射噪声,通过对微通道板输入面蒸镀Ni-Cr电极后对反射率影响的定性分析以及镀膜方式、镀层厚度、电极深入通道内的深度和微通道板的开口面积比等测试分析,在兼顾微通道板对输入电极其他要求的前提下,获得了降低反射率的有效技术途径,即:采用电子束加热的蒸镀方式,用表面电阻大小来间接表征膜层厚度,使其控制在100 左右;电极深入通道内的深度为通道直径的35%;微通道板的开口面积比尽可能大些,可把反射率降低到4%以下,以此降低微光像增强器的光子散射噪声。

     

    Abstract: To reduce scattered noise which results from photons reflected by transparent or semitransparent photocathode at input surface of microchannel plate (MCP), the qualitative analysis of its influence on reflectance of the MCP input surface electrode and the test investigation of electrode film coating, film thickness, electrode depth, and open area ratio of MCP were given. Based on the influence of MCP input electrode on other MCP parameters, a technical solution was obtained which adopted electron gun to heat Ni-Cr alloy for electrode film coating and implemented the control of film thickness by keeping a constant resistance of 100, the electrode depth in channel accounted for 35% of channel diameter and the open area ratio of MCP was as larger as possible. Finally, the reflectivity of MCP input surface electrode is reduced to less than 4% and the photon scattered noise of image intensifier is decreased.

     

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