Review of klystron modulator technology for particle accelerators

Modern, continuously operating particle accelerators require large power, highly stable, radio frequency power generators to provide the sinusoidal electric field for acceleration. The most common and efficient method of generating RF power is the klystron, which is further powered by a microsecond scale, high voltage, moderate current pulse power source at moderate pulse rates. The most commonly used klystron modulator consists of a thyratron switched pulse forming line and a voltage step up transformer, which is termed a "line modulator". This paper describes the common line type modulator, the individual components, the specifications, and the cost breakdown for a typical system. The objective of this paper is to investigate the methods of designing modulators for the next generation of particle accelerators, and to evaluate circuit and component options for improving the performance to cost ratio. A large number of klystrons and thus klystron modulators will be required for any next generation particle physics accelerator and thus, the reliability and the cost of the individual components are critical parameters that will determine the feasibility of building any pulse power klystron modulator system. This paper also discusses reliability and cost issues associated with klystron modulator system and component design and implementation.