半导体光阴极是驱动未来高平均功率短波长自由电子激光的最关键电子源之一。阴极在高平均功率状态下的工作寿命是目前限制半导体光阴极用于高重复频率高亮度电子源的核心物理问题。本课题围绕中国工程物理研究院现有的负电子亲和势砷化镓光阴极注入器，拟针对下一代先进光源驱动电子源，对砷化镓光阴极工作寿命的影响机制进行探索性研究，主要研究内容包括：①综合真空度、温度和离子反轰三大影响因素，建立砷化镓光阴极工作寿命的定量物理模型；②通过蒙特卡洛模拟，探索离子反轰和杂散光对工作寿命的影响机制；③优化实现电子束高平均功率高亮度稳定输出。本课题的研究成果将为未来高平均功率高亮度光阴极注入器提供理论与实验支持。

Semiconductor photocathode electron source plays a significant role in the path to the realization of the future high average power short wavelength free electron lasers. At high average power operation status,one of the major physical problems is the operational lifetime of photocathode, which is also the main limitations of the photocathode technology development. In this project, the influence mechanisms of the operational lifetime will be explored based on the negative electron affinity (NEA) GaAs photocathode high-voltage DC electron injector which has been assembled in China Academy of Engineering Physics (CAEP). The research includes the following aspects: 1. The establishment of a quantitative physical model of operational which takes all the factors that affect the NEA GaAs operation life-time into account, i. e., vacuum, temperature and ion back-bombardment; 2. The exploration for lifetime influenced by ion back-bombardment and stray photons with Monte Carlo simulations; 3. Some experiments to realize long time high average current beam delivery of the DC injector. The methods and results of these studies can provide theoretical and experimental support for the future high average power high brightness photocathode-injectors.