Bnl photo-injector performance optimization

Extensive simulation studies of the BNL 1.6 cell photoinjector were carried out at the Accelerator Test Facility (ATF) using computer program PARMELA. The transverse emittance of photo-injector was optimized at much lower RF gun phase than earlier studies, which agrees with the longitudinal emittance compensation predictions. The Schottky effect on the emittance and pulse length of photoelectron beam was investigated. Instead of flat longitudinal distribution, simple laser and electron beam longitudinal profile control techniques, such a laser pulse truncation by saturable absorber, or electron beam longitudinal beam profile truncation using energy slit, were used to achieve transverse emittance 1 mm-mrad for a charge of 1 nC.