RF power source for the compact linear collider test facility (CTF3)

The CERN CTF3 facility will test and demonstrate many vital components of CLIC (Compact Linear Collider). This paper describes the pulsed RF power source at 2998.55 MHz for the drive-beam accelerator (DBA), which produces a beam with an energy of 150 MeV and a current of 3.5 Amps. Where possible, existing equipment from the LEP preinjector, especially the modulators and klystrons, is being used and upgraded to achieve this goal. A high power RF pulse compression system is used at the output of each klystron, which requires sophisticated RF phase programming on the low level side to achieve the required RF pulse. In addition to the 3 GHz system two pulsed RF sources operating at 1.5 GHz are being built. The first is a wide-band, low power, travelling wave tube (TWT) for the subharmonic buncher (SHB) system that produces a train of "phase coded" subpulses as part of the injector scheme. The second is a high power narrow band system to produce 20 MW RF power to the 1.5 GHz RF deflectors in the delay loop situated immediately after the DBA.