Modifications on RF Components in the LCLS Injector

Design of the first generation LCLS injector is nearing completion. Fabrication has begun and component installation is planned for 2006. We discuss the last modifications made on both the 1.6 cell S-Band RF gun and the SLAC S-Band accelerating structures to minimize irreversible emittance growth. The mode separation between the 0 and π modes was increased from 3.4 MHz to 15 MHz. Dual feed and racetrack shapes have been incorporated in the full cell of the new gun. The linac sections were also modified to accommodate dual feeds and racetrack shapes in their input cells. PARMELA simulations indicating the need for these modifications are presented.