Analysis of the 425-MHz Klystrode

The results of analyses performed on a 500-kW peak power, 425-MHz Klystrode are presented. The Klystrode is an RF amplifier with three basic components; a gated-emission gun, a resonator (output cavity), and a spent-beam collector. The principal goal of the analysis is to understand the factors that limit the efficiency of the Klystrode and to suggest approaches to achieving improved efficiency. Numerical simulations were performed with the fully electromagnetic, two-and-one-half-dimensional, self-consistent particle-in-cell code, MAGIC. A resonator saturation theory was developed to predict Klystrode performance from startup to saturation. Based on this theory, a one-dimensional optimizing code KLYDE, was developed to address the design tradeoffs. These tools have been employed to investigate the Klystrode performance over a wide range of parameters with good agreement between MAGIC, KLYDE, theory and experiment. The analyses suggest that shortening the bunch length is the most effective way to achieve higher efficiencies