Computer determination of HOM damping for a prototype JLC accelerator cavity and a prototype B factory cavity

The authors describe the determination of the properties of accelerator cavities with particular emphasis on the damping of the higher order modes (HOMs). Because mode frequency spectra were determined for a large number of shorted waveguide lengths, a complete overall analysis of the mode spectrum was possible. Phase frequency plots have proved to be an invaluable aid in sorting out overlapping resonances and separating cavity resonances from waveguide resonances. Algorithms for the determination of the parameters of several resonances simultaneously have been developed. Determinations of Q from multiresonance analyses are compared to those from single resonance analyses, and the changes are typically found to be small.<>