Bente "The photoinjector option for CLIC: past experiments and future developments

The Compact Linear Collider (CLIC) drive beam re-quires a long bunch train (92s) consisting of 42880 bunches with a bunch charge of 17.5 nC in a bunch length of less than 20 ps. This train might be produced by an RF-photo-injector equipped with a Cs-Te cathode. After a short review of experience with such cathodes in the present CLIC Test Facility (CTF2), mainly focused on the produc-tion of short trains of high-charge bunches, we will present the scheme foreseen for CLIC and CTF3. The laser will be a diode-pumped MOPA (Master Oscillator Power Am-plifier), operating at a repetition rate of 469 MHz for CLIC and 1.5 GHz for CTF3. The specific requirements of an RF-gun for this high-current operation are discussed. New experimental results on the photocathode lifetime at hig