The SPARC RF Synchronization System

The SPARC project [1] consists in a 150MeV Linac aimed at driving an ondulator for the production of 530nm SASE FEL radiation. A bunch transverse emittance as low as 1mm mrad and a bunch peak current of about 100A are required for this task. The RF voltages in the RF gun and in the 3 S-band accelerating sections have to be kept phase locked within 3ps to the arrival time of the laser pulse on the photocathode to guarantee the required performances. This specification will be reduced to 0.5ps in the phase II of the project when the rectilinear RF compression of the bunch will be tested. The general architecture of the SPARC RF control system together with some bench qualification measurements of the basic components is presented in this paper.