Fabrication and Measurement of Low Workfunction Cesiated Dispenser Photocathodes

A requirement for high power free electron lasers (FEL) is a high current, high quality electron beam. This is achieved using a laser-switched photocathode. Even state-of-the-art high, efficiency photocathodes suffer from short lifetime, because contamination and evaporation processes damage the surface monolayer of photosensitive material. This research seeks to improve both efficiency and lifetime through a novel dispenser cathode, where the photosensitive layer is regenerated in situ. During regeneration, photosensitive material from a sub-surface reservoir diffuses to the surface through microscopic pores to repair the damaged layer. The goal of this research is to design and prototype a robust, low-workfunction regenerable photocathode which exhibits long lifetime and high efficiency.