Exploratory study of X-band Klystron designs for maximum efficiency

Results are reported from an exploratory study of high efficiency X-band klystron designs. A variety of simulation tools are used to determine the peak achievable efficiency as a function of beam and circuit parameters. The core oscillation method is used for the bunching circuit, which is optimized independently of the multiple- gap output circuit. Substantial improvements in efficiency are predicted relative to the existing SLAC XL5 klystron.