The L-band klystron-modulator RF power system for CLIC

The long-pulse, high-power klystron-modulators are an important part of the CLIC drive-beam scheme and a number of design variations are being studied in order to improve their overall power efficiency, reliability and cost effectiveness. Because of the number needed (364 at 50 MW for the 3 TeV scheme) and their size, they will have a large impact on the capital cost of the pulsed RF power to be delivered to the beam and to the resistive losses in the drive-beam accelerating structures. Overall RF system efficiency is an important parameter for long linear colliders, and to a large extent, will be determined by the performance and efficiency of the klystron-modulators. The input AC power to output RF power efficiency of one CLIC klystron- modulator, including the klystron, power conversion, pulse transformer, auxiliary power and switching losses at 100 Hz and 100 mu s pulse width, is estimated as 52The RF to beam efficiency is estimated at 24, and after taking into account other RF power transmission losses within the systems the overall AC to beam efficiency will be about 10(3 refs).