An injector for the proposed Berkeley ultrafast X-ray light source

Berkeley Lab has proposed to build a recirculating linac based X-ray source for ultra-fast dynamic studies [J. Corlett, et. al., "A Recirculating Linac-Based Facility for Ultrafast X-ray Science", Proc. 2003 Part. Accel. Conf., Portland, 2003.]. This machine requires a flat electron beam with a small vertical emittance and large x/y emittance ratio to allow for compression of spontaneous undulator emission of soft and hard x-ray pulses, and a low-emittance, round electron beam for coherent emission of soft x-rays via the FEL process based on cascaded harmonic generation [W. Fawley, et. al., "Simulation Studies of an XUV/Soft X-Ray Harmonic-Cascade FEL for the Proposed LBNL Recirculating Linac;, Proc. 2003 Part. Accel. Conf., Portland, 2003.]. We propose an injector system consisting of two high gradient high repetition rate photocathode guns [J. Staples, et. al., "The LBNL Femtosource 10 kHz Photoinjector\´, Proc. 2003 Part. Accel. Conf., Portland, 2003.] (one for each application), a ∼120 MeV superconducting linear accelerator, a 3rd harmonic cavity for linearization of the longitudinal phase space, and a bunch compressor. We present details of the design and the results of particle tracking studies using several computer codes.