Design for A 1.3 MW, 13 MeV Beam Dump for an Energy Recovery Linac

The electron beam exiting an Energy Recovery Linac (ERL) is dumped at an energy close to the injection energy. This energy is chosen to be as low as possible consistent with meeting the beam quality specifications. ERLs operate with high average beam current, requiring the dump 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 to be large enough to give acceptable energy deposition and heat flux in the dump. 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 the abrupt thermal cycles associated with beam trips is a potential failure mechanism. We expect to test a 500 kW, 5-15 MeV dump of this design within about 2 years.