Increasing Electron Source Brightness to Extend the Spectral Range of X-Ray Free-Electron Lasers
The colloquium will present a general overview of X-ray free-electron lasers such as the LCLS-I and LCLS-II and will briefly discuss the planned LCLS-II high energy upgrade. Electron source brightness will be defined and the connection between electron source brightness and the output of an X-ray free-electron laser will be made. Efforts at SLAC National Accelerator Laboratory to increase electron source brightness will then be presented. This includes electron gun development at SLAC, such as the recently re-commissioned superconducting RF photogun. Also included will be a discussion of desirable photocathode properties and a density functional theory-based method for predicting and optimizing photocathode performance.