MAGNETIC LOSSES AND INSTABILITIES IN FERRITE-GARNET TUNED RF CAVITIES FOR SYNCHROTRONS

The aim of this paper is to introduce basic concepts and elucidate the main features of magnetic losses and nonlinear effects in high-power rf cavities in which perpendicularly biased ferrite garnet is used for varying the frequency in rapid cycling synchrotrons. A method of analysis is developed using a minimum of specific details. Simple formulae and estimates of the trend of magnetic loss, nonlinear frequency shift, and possible instabilities in the cavities as a function of rf power level and ferrite garnet parameters are presented. Numerical examples correspond to the TRIUMF KAON Booster synchrotron.