Development of a high-brightness photoinjector for Compton scattering x-ray sources*

Compton scattering of intense laser pulses with ultra-relativistic electron beams has proven to be an attractive source of high-brightness x-rays with keV to MeV energies. This type of x-ray source requires the electron beam brightness to be comparable with that used in x-ray free-electron lasers and laser and plasma based advanced accelerators. We describe the development of a 1.6 cell RF photoinjector for use in Compton scattering experiments at LLNL. RF cavity design, beam dynamics simulations, emittance diagnostic development, and results of sputtered magnesium photo-cathode experiments are discussed. The photo-cathode drive laser is described and injector performance goals are presented.