AVS 66th International Symposium & Exhibition
    Vacuum Technology Division Monday Sessions
       Session VT-MoA

Paper VT-MoA5
Photocathode Growth and Diagnostic Systems for LCLS-II

Monday, October 21, 2019, 3:00 pm, Room A213

Session: Gas Dynamics, Surface Science for Accelerators, and Ultra-Clean Vacuum Systems
Presenter: Xianghong Liu, SLAC National Accelerator Laboratory
Authors: X. Liu, SLAC National Accelerator Laboratory
T. Vecchione, SLAC National Accelerator Laboratory
B. Dunham, SLAC National Accelerator Laboratory
Correspondent: Click to Email
We have designed and manufactured a multisource physical vapor deposition system for producing photocathodes to be used in the LCLS-II, a hard X-ray free electron laser accelerator facility at SLAC. The photocathodes currently produced are thin film Cs2Te, but the system has the capability to integrate up to four independent sources permitting the future growth of ternary and quaternary compounds. The deposition system has a load-lock which permits photocathodes to be transferred into and out of the system without breaking vacuum. The geometry of the photocathode substrate is adopted from INFN, so photocathodes can be exchanged between systems and institutions that share the same design using a vacuum suitcase. We have also designed a diagnostic system for characterizing photocathode performance and are in the process of manufacturing this system. The system is capable of measuring the quantum efficiency and transverse momentum distributions of photoemitted electrons. The wavelength dependence of these measurements can be recorded as a function of temperature down to below 10 K. We will present the designs of these systems and report on their operational status and early results.