V型级联微通道板纳秒响应近贴聚焦像增强器研究

Novel Type of Proximity Focus Image Intensifier with Nano-Second Response in V-Shaped Double Micro-Channel-Plate Asembly

为解决单片微通道板(MCP)近贴聚焦像增强器在强脉冲光照射下输出图像失真、脉冲响应时间慢的问题,对光电阴极面电子发射过渡过程进行理论分析,得出半导体阴极发射层电阻大、光电阴极和荧光屏与MCP间的距离大、器件增益低是造成器件响应时间慢的主要根源。因此采用在阴极发射层底面真空蒸镀100 nm厚半透明金属导电膜、阴极与MCP输入面间距从0.4减小到0.15 mm、荧光屏与MCP间距从0.8减小到0.5 mm和双MCP级联等措施,制成了脉冲时间小于2 ns,增益达到106的纳秒响应像增强器,满足了核技术研究需求。文章中给出了像增强器的结构、技术指标及器件改进前后的时间响应曲线,并指出了器件的应用前景。

Here,we addressed the problems of image distortion and slow pulse response-time of the proximity focus image intensifier with single micro-channel-plate（ MCP）. The negative impact of the emission conditions,including the large sheet-resistance of the semiconductor emission layer,big distances between photoemission surface and MCP front-side and between MCP back-side and screen,and low MCP gain,on image distortion and slow response-time was theoretically investigated. The effective solutions included a 10 nm semi-transparent metal layer deposited on the bottom of photo-emission layer to reduce sheet resistance; a decrease of photocathode / MCP distance from 0. 4 to 0. 15 mm,a reduction of screen / MCP separation from 0. 8 to 0. 5 mm,and a V-shaped arrangement of double-MCP assembly to shorten the pulse response-time to below 2 ns and increase MCP gain up to 106. The test results show that the newly-developed proximity focus image intensifier meets the stringent requirements in RD of nuclear technology.