Setup for Cooled GaAs Cathodes With Increased Charge Lifetime

GaAs photocathode lifetime is limited, and to ensure re- liable operation for high power-applications it is necessary to maximize its charge lifetime. By using a cryogenic sub- volume it is expected to improve the local vacuum condi- tions due to cryogenic adsorption of reactive residual gas molecules. Yielding an enhanced lifetime of the negative- electron-affinity surface of the cathode. Furthermore the cooling of the cathode itself ishould allow higher laser power deposition in the material. Introducing an electrostatic bend is expected to reduces the ion-backbombardment on the cath- ode surface. A dedicated set-up is being developed at the Photo-CATCH test facility in Darmstadt, Germany to measure the charac- teristics of such a cryogenic source. This contribution updates the report given at PSTP 2017.
Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada