Development and advances in conventional high power RF systems

The development of RF systems capable of producing high peak power (hundreds of megawatts) at relatively short pulse lengths (0.1-5 microseconds) is currently being driven mainly by the requirements of future high energy linear colliders, although there may be applications to industrial, medical and research linacs as well. The production of high peak power RF typically involves four basic elements: a power supply to convert AC from the "wall plug" to DC; a modulator, or some sort of switching element, to produce pulsed DC power; an RF source to convert the pulsed DC to pulsed RF power; and possibly an RF pulse compression system to further enhance the peak RF power. Each element in this RF chain from wall plug to accelerating structure must perform with high efficiency in a linear collider application, such that the overall system efficiency is 30% or more. Basic design concepts are discussed for klystrons, modulators and RF pulse compression systems, and their present design status is summarized for applications to proposed linear colliders.