Beam dynamics studies in the CLIC Injector LINAC

The CLIC Injector Linac has to accelerate both electron and positron main beams from 200 MeV up to 2.42 GeV prior to their injection into the pre-damping rings. Its 26 accelerating structures operate at 1.5 GHz, with a loaded gradient of 17 MV/m. A FODO lattice that wraps the accelerating structures at the beginning of the linac, followed by a succession of triplet lattices between the accelerating structures, is proposed. The large normalized transverse emittance (9200 mm.mrad rms), bunch length (5 mm rms) and energy spread (7 MeV rms) of the e⁺ beam set constraints on the linac, in order to reach acceptable characteristics at 2.42 GeV for the injection into the pre- damping ring. The use of a bunch compressor at the linac entrance is an option in order to achieve good performance in both the longitudinal and transverse phase spaces. Tracking studies of both electron and positron beams in the linac have been performed and are presented.