• C.K. Sinclair
  Cornell University, Department of Physics, Ithaca, New York
• Y. He, C.H. Smith
  Cornell University, Ithaca, New York

The electron beam exiting an Energy Recovery Linac (ERL) is dumped close to the injection energy. This energy is chosen as low as possible while allowing the beam quality specifications to be met. As ERLs are designed for high average beam current, beam dumps are required to handle high beam power at low energy. Low energy electrons have a short range in practical dump materials, requiring the beam size at the dump face be enlarged to give acceptable power densities and heat fluxes. Cornell University is developing a 100 mA average current ERL as a synchrotron radiation source. The 13 MeV optimum injection energy requires a 1.3 MW beam dump. We present a mature design for this dump, using an array of water-cooled extruded copper tubes. This array is mounted in the accelerator vacuum normal to the beam. Fatigue failure resulting from abrupt thermal cycles associated with beam trips is a potential failure mechanism. We report on designs for a 75 kW, 750 keV tube-cooled beryllium plate dump for electron gun testing, and a 500 kW, 5 to 15 MeV copper tube dump for use with the prototype injector under development. We expect to test the beryllium dump within a year, and the higher power copper dump within 2-1/2 years.