A Proposal for a High Current, High Duty Factor Electron Accelerator

A linac-Pulse-Stretcher-Ring has been proposed for the generation of high duty factor, high current electron beams in a nominal energy range of 0.5 to 2.0 GeV. A low duty factor linac beam is injected into a storage ring from which it is slowly extracted to yield a high duty factor. The linac beam is composed of 1.2 ¿s current pulses containing 240 nC/pulse with a repetition rate of 1 kHz. Each pulse is injected vertically during a single turn into the pulse stretcher ring, a 377.89 m oval with a magnetic radius of 29 m. Excitation of an n/3 betatron resonance in the horizontal plane is used in conjunction with electric and magnetic septa for extraction. Typical extracted beam parameters are: horizontal emittance ¿0.37¿ mm-mrad, vertical emittance ¿0.l¿ mm-mrad, and an energy spread ¿0.1%. The extracted beam has a maximum average current of 240 ¿A, a duty factor >90%, and may be polarized. Beam characteristics, design parameters, and facility layout are discussed.