温差法降低碱金属对倒像管沾污的研究

Reduction of Alkali Vapor Contamination in Invert Image Intensifier Tube by Temperature Difference Technique

所谓温差法就是在制备 2 0 / 30倒像管多碱阴极过程中 ,将像管后半部分套一可控温小电炉 ,使荧光屏和微通道板(MCP)等部位的温度始终比阴极基底高 10 0℃左右 ;阴极制备结束后 ,取下管内的MCP进行XPS分析 ,同时还与用标准工艺制备阴极后取下的MCP进行对比分析。XPS谱图表明 ,前者检测到的Na为 3 0 7% ,K为 2 2 3% ,Cs为 0 0 0 % ;后者检测到的Na为 6 32 % ,K为 2 70 % ,Cs为 0 36 %。实验说明 ,在制备阴极过程中 ,阳极筒和荧光屏端温度高于阴极面激活温度 ,使得吸附在MCP电极表面以及阳极筒等高温部件的碱金属 ,尤其是Na的含量降低。从而说明温差法是降低碱金属蒸气对像管内其它部件的污染 ,改善背景噪声的有效方法之一。

A novel temperature difference technique,which considerably reduces alkali vapor contamination,has been successfully deve- loped in fabricating the multi alkali cathodes of the 20/30 invert image intensifier tube.In cathode fabrication,a temperature controllable oven is introduced to raise the temperature of the bottom part of the tube,which contains the screen and the microchannel plate (MCP),100 ℃ higher than the front part.The MCP sample was studied with X-ray photoelectron spectroscopy (XPS).XPS results show that the alkali vapor contamination has been significantly reduced,The concentrations of Na,K,and Cs are 3.07%,2.23% and 0.00%,respectively,whereas for the control sample,fabricated in conventional technique,the concentrations of Na,K,and Cs are 6.32%,2.70% and 0.36%,respectively.