多碱阴极光学反射率监控

介绍了在一代象增强器多碱阴极制备过程中，对光学反射率进行连续监控的装置，并对试验结果作了简单的分析。研究结果表明，Ｎａ２ＫＳｂ材料在制备过程中是逐层生长的，在锑、钾交替过程中，其化学置换反应仅发生在表面层一定的厚度内。多碱阴极的实测反射率曲线越接近理论曲线，其灵敏度也越高。多碱阴极膜层厚度的增加，可以导致其长波响应的增加。对一代象增强器而言，多碱阴极的最佳厚度约为１２０ｎｍ。

Reflectance Monitoring on Multialkali Photocathode Layer Growth

On line measurements on the reflectance of multialkali photocathode in the first generation image intensifier is presented,and experiment appratus and results are illustrated.It is shown that the ultimate Na 2KSb layer is the result of alternative growth between Sb and K layers.During co evaporation of Sb and K,its substitution happens within a certain thickness of Na 2KSb surface.The closer the measuring reflectance curve to the theoretical reflectance curve,the higher a photocathode sensitivity is.With increasing the thickness of a photocathode,longwave response increases.The optimium thickness of a photocathode is about 120nm for the first generation image intensifier.