锑钾铯光阴极制备系统

A preparation system for potassium cesium antimonide photocathode

双碱金属锑化物光阴极在可见光下有高量子效率(QE)、低发射度和强射(RF)频电场,实用真空下寿命较长,产生的高亮度电子束团满足能量回收型直线加速器要求。此类光阴极都含有元素Cs,需在超高真空(UHV)下制备、转移及工作。本文简述了SINAP的双碱金属锑化物光阴极制备装置及各种仪器功能,提出了UHV获得、光阴极基底清洗和K-Cs-Sb光阴极制备过程的方案。通过实验测量了K-Cs-Sb光阴极QE与激光入射功率密度和波长的关系,并构想了基于此制备装置的K-Cs-Sb光阴极的其它性能测试实验。

A bialkali antimonide photocathode is of high quantum efficiency （QE） for visible lights, low emittance, and relatively long life time in the strong RF field and practical vacuum. It produces high-brightness electron beams to meet the energy recovery need of a linac. This kind of photocathode contains cesium, hence the need of preparing, transferring and operating it in ultra high vacuum （UHV）. In this paper, we report the design of a bialkali antimonide photocathode preparation apparatus developed at SINAP. Functions of the equipment are described. The UHV pumping, the photocathode substrate cleaning and preparation the K-Cs-Sb photocathode are presented in detail. The QE is measured under different laser power densities and wavelengths. Other testing experiments for performance of the K-Cs-Sb photocathode prepared with this apparatus are conceived.