Some aspects of superconducting accelerator design

The performance of an accelerator can be characterized by the efficiency with which electrical energy, ac and rf, is converted into accelerating energy, the minimum energy needed to generate a given beam voltage. The current accelerator improvement program at SLAC aims at raising the beam voltage to 50GV which will use 240 klystrons each capable of producing a pulse 5μs in length at a peak power of 36MW. The Linear Collider requires 50MW klystrons to achieve 60GV which will raise the concomittant power consumption to 32.3MW. We show that with superconducting elements we can increase the rf and ac conversion efficiencies and achieve the necessary 60GV using only 1/3 of the present power requirements, provided that we exclude CW operation. We will further demonstrate that this increase in efficiency is crucial and highly significant in the design of a proposed 1000GV linear accelerator.