Author: Maldonado, J.R.
Paper Title Page
TUPPD076 Photocathode Studies for the SPEAR3 Injector RF Gun 1575
  • S. Park, W.J. Corbett, S.M. Gierman, J.R. Maldonado
    SLAC, Menlo Park, California, USA
  Funding: Work supported by U.S. Department of Energy Contract DE-AC03- 76SF00515 and Office of Basic Energy Sciences, Division of Chemical Sciences.
The electron gun for the SPEAR3 injector operates with a warm thermionic dispenser cathode immersed in a 1.5-cell RF structure. At each injection cycle the gun accelerates several thousand electron bunches up to ~3 MeV during a 2.5us rf pulse. The individual bunches are then compressed by an alpha magnet and a traveling-wave chopper selects 3-5 bunches so they don’t cause beam loading to the linac, where the accelerated bunches reach 120 MeV for subsequent capture in a single booster synchrotron bucket. Tests are underway to operate the dispenser cathode as a cold electron photo-emitter driven by an external laser system. Eventually, without the copper, this will enable multi-bunch injections to the Booster and SPEAR3. In parallel, tests are underway to evaluate quantum efficiency and beam emittance for a beam emitted from a CsBr photocathode with ns- and ps-pulses of UV laser light. In this paper we report on both the cold cathode electron gun operation studies for SPEAR3 and the CsBr research aimed at developing advanced cathode materials for future applications.