Laser system for the TTF photoinjector at Fermilab

A.R. Fry, M.J. Fitch, A.C. Melissinos, N.P. Bigelow, B.D. Taylor, F.A. Nezrick
Proceedings of the 1997 Particle Accelerator Conference (Cat. No.97CH36167)  
We have developed a solid-state laser system to meet the requirements of the TESLA Test Facility (TTF) photoinjector, currently under development at Fermilab. The laser produces a 1 MHz train of up to 800 equal-amplitude pulses with up to 1 mJ per pulse (0.8 J per macropulse) at λ = 1054 nm. The laser pulse train is produced by a phase-stabilized, mode-locked, Nd:YLF oscillator and a fast selection Pockels cell. The pulses are amplified in an Nd:glass amplifier chain consisting of a multipass
more » ... ng of a multipass rod amplifier and a 5-pass zig-zag slab amplifier. The laser system employs chirped pulse amplification (CPA) to produce 10 ps pulses. After fourth harmonic generation of the laser to λ = 263 nm, 10 nC electron bunches can be extracted from a Cs 2 Te photocathode in the RF gun. TTF PHOTONINJECTOR DEVELOPMENT A collaboration has been formed between FNAL, DESY, UCLA, INFN Milano, and the University of Rochester to develop a state-of-the-art photoinjector with a novel bunch structure for the Tesla Test Facility (TTF). The injector will consist of an RF gun[1] (UCLA, FNAL) with a highquantum efficiency photocathode[2] (INFN Milano) driven by an advanced laser system[3] (Rochester), and a superconducting linear accelerator cavity (DESY). The FNAL/TTF RF photoinjector is designed to match the requirements of the TTF accelerator[4], namely high bunch charge (8 nC), low emittance (< 20 mm-mr) and high duty cycle (1%). The TTF pulse train consists of 800 bunches of 8 nC, spaced 1 µs apart, with a 10 Hz rep rate. The beam optics are optimized for an overall injector consisting of the electron gun followed by one linac capture section and a dipole chicane for magnetic bunch compression [1] .
doi:10.1109/pac.1997.752845 fatcat:hymr3kyvxrd6lljnria2hi4ujm