利用铝屏和氧化铟锡(ITO)屏两种结构的微通道板(MCP)成像器进行了放电实验, 通过直流首击穿后器件的绝缘强度和电极熔蚀形貌变化, 分析了屏电极结构对放电的影响。实验表明, 铝屏MCP成像器首击穿后, 铝膜电极出现如火山口状的熔蚀形貌, 在10 μs脉冲屏压下绝缘强度降低到3 kV/mm以下, 绝缘强度与MCP无关。而ITO屏MCP成像器首击穿后, 荧光质向MCP的质量迁移具有抑制阴极发射的作用, 所以放电具有稳定的场发射特性, 在10 μs脉冲屏压下绝缘强度可达到9 kV/mm。分析表明, MCP成像器间隙放电的发展主要依赖于屏电极结构, ITO屏的电极结构有利于MCP成像器绝缘性能的提高。

The vacuum-gap discharge damage of micro-channel plate(MCP) imagers based on two screen-electrode structures, with Al-screen and indium-tin-oxide(ITO) screen respectively, is investigated after first arcing. The results show that the erosion pattern of Al-screen MCP imager appears as crater, and the electric insulating strength is less than 3 kV/mm under 10 μs-wide screen voltage, independent of MCP. The erosion of ITO-screen mostly appears as phosphor transporting to MCP, which drives field emission to steady state, and the electric insulating strength can reach 9 kV/mm at 10 μs-wide voltage. Thus, the discharge of MCP imagers depends mostly on screen-electrode structure, and ITO-screen MCP imagers can obtain higher electric insulating strength.