Externally powered dielectric loaded waveguides as accelerating structures

There have been numerous studies examining the use of dielectric materials in accelerating structures in the past. Such studies and related experiments generally concluded that dielectric losses, with the resulting high power requirements, and field breakdown problems made such devices not very attractive. However, development of high dielectric constant, low loss materials plus new demands for emittance preserving acceleration warrant a new look at the idea. In this paper, we discuss reference parameter designs for S-band and X-band structures and show that dielectric loaded guide may now be practical and have certain advantages over conventional iris loaded structures. Preliminary experimental test results of X-band dielectric devices are reported.