WG1005
CLASSE, Ithaca, New York, USA
One of the key requirements for an Energy Recovery Linac (ERL) is to have a 1.3 GHz, high-power laser source that is used to drive the ERL photocathode gun. Here we present a fiber master oscillator power amplifier (MOPA) system that could potentially meet this important need. We start with 1.3GHz oscillator emitting a chirped 8 ps pulse train. Through two preamp stages and one main amplifier, an average IR power of 135 Watts was obtained. After de-chirping the optical pulses, frequency doubling yields more than 50 Watts green light at 520 nm. It is anticipated that such a laser source could be employed to generate up to 100 mA average current electron source in the ERL at Cornell University.
WG1019
Cornell University, Ithaca, New York, USA
CLASSE, Ithaca, New York, USA
The electron beam brightness in a Linac is limited by the beam brightness at the photocathode. Various photocathode materials are being investigated at Cornell University to optimize the Quantum Efficiency (QE), emittance, response time and lifetime. The photocathode growth procedures and diagnostic techniques being developed at Cornell University are presented. GaAs(Cs,F) and alkali-antimonide are the two kinds of high Quantum Efficiency (QE) photocathodes which are being investigated for use in the Cornell High Energy ERL. GaAs(Cs,F) has the potential to produce sub-thermal emittance electron beams whereas K2CsSb has demonstrated the ability to deliver 20mA of beam current for 8 hours without significant QE decay.