Generation and applications of ultrashort electron beams in energy-recovery linacs

Hajima, Ryoichi; Nakamura, Norio*; Shimada, Miho*

Energy-recovery linac (ERL) is a novel type of accelerator to generate an electron beam of high quality and high average current. In an ERL, an electron beam from an injector is accelerated by time-varying RF field stored in a superconducting linac and the beam is transported to a recirculation loop. After the recirculation loop, the beam is decelerated by the same superconducting linac for the energy recovery. In this talk, challenges for the generation of ultrashort electron bunches in ERLs are discussed, and applications of ultrashort electron bunches from ERLs are presented.