Advanced photoinjector laser and microwave technologies. Final report

An overview of the design parameters of the compact, high gradient, high luminosity X-band (8.568 GHz) photoinjector facility currently being developed as a collaborative effort between LLNL and UC Davis, is followed by a more detailed description of each of its major subsystems : X-band rf gun, GHz repetition rate synchronously modelocked AlGaAs quantum well laser oscillator, and 8-pass Ti: Al{sub 2}O{sub 3} chirped pulse laser amplifier. The photoinjector uses a high quantum efficiency ({approx}5%) Cs{sub 2}Te photocathode, and will be capable of producing high charge (> 1 nC), relativistic (5 MeV), ultrashort (< 1 ps) electron bunches at 2.142 GHz repetition rate in burst mode (100 photoelectron bunches). Design studies indicate that a normalized rms transverse emittance {epsilon}{sub n} = 0.75 {pi} mm-mrad is possible at 0.1 nC charge, while 2.5 {pi} mm-mrad can be obtained at 1 nC. A complete status report of our progress in the development and implementation of the design discussed herein is then given, together with initial experimental data concerning the performance of the 15 MW SLAC X-band klystron amplifier. Finally, the phase noise and jitter characteristics of the laser and rf systems of the high gradient X-band photoinjector have been measured experimentally. In this case, the laser oscillator is a self-modelocked Titanium:Sapphire system operating at the 108th subharmonic of the rf gun. The X-band signal is produced from the laser by a phase-locked dielectric resonance oscillator, and amplified by a pulsed TWT. A comparison between the TWT phase noise and the fields excited in the rf gun demonstrates the filtering effect of the high Q cavity resonant structure, thus indicating that the rf gun can be used as a master oscillator, and could be energized by either a magnetron or a cross-field amplifier