Design Study of Cusptron Amplifier for Accelerators

Research and development of an RF source for next generation electron-positron colliders is proposed based on the newly developed cusptron microwave tubes. The cusptron generates high harmonics of the electron cyclotron frequency by resonant interaction of an axis-encircling electron beam and the modes in a multi-vane conducting wall structure. The strong coupling through the negative mass instability, the relatively low magnetic field requirement, the high current capability, and multi-feed possibility are some of the features of the cusptron that are especially suited for the accelerator applications. The intended parameters for prototype cusptron are P = 100 MW peak power at f = 8.5 GHz using P = 240 MW beam. In order to reach this ultimate goal, first the scaling law of the beam and field parameters for the cusptron is examined, and the RF circuit design in conjunction with these beam parameters are presented. The design parameters for the scaled down experiments, intended as intermediate steps and tests for the scaling laws, are also given.