A low emittance and high efficiency visible light photocathode for high brightness accelerator-based X-ray light sources

Free-electron lasers and energy recovery linacs represent a new generation of ultra-high brightness electron accelerator based x-ray sources. Photocathodes are a critical performance-limiting component of these systems. Here, we describe the development of photocathodes based on potassium-cesium-antimonide that satisfy many of the key requirements of future light sources, such as robustness, high quantum efficiency when excited with visible light, and low transverse emittance. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3612916]