GaAs-玻璃粘接透射式阴极光电发射在线稳定性研究

Photoemission Stability of Glass Cemented GaAs Transmission Cathode

为了寻找三代像增强器管内阴极灵敏度下降产生的原因,用质谱计作为质量监测手段,通过对阴极原子级洁净表面获得、阴极激活铯、氧提纯工艺参数优化研究,所制备的透射式GaAs阴极光电发射稳定性进行在线考核试验,结果表明,优化工艺激活的光电阴极在真空度10-9Pa,主要残气为H2、N2、Ar的超高真空度中存放500 h,灵敏度稳定。铟封到管内阴极灵敏度下降与真空度降低和有害气体污染有关,不是阴极自身的问题,重点应开展制管工艺质量对灵敏度影响分析研究。

Here, we addressed the on-line stabihty of the glass-cemented, GaAs transmission cathode photoemission to find possible solutions for the sensitivity degradation of the 3rd generation, low-light-level （LLL） image intensifiers. The impacts of the fabrication processes, including the surface cleaning and degassing, Cs activation, and purity of oxygen, on stability of the photoemission were evaluated with mass-spectroscopy as the major probe. The results show that the pressure build-up and contamination of harmful residual gases in the indium-sealed tube strongly degrade the photoemission sensi- tivity. Under optimized fabrication and activation conditions, the photoemission sensitivity remained stable for at least 500 h at a pressure of 10-9 Pa,mainly consisting of H2,N2 and Ar.