Cyclotron autoresonance maser (CARM) amplifiers for RF accelerator drivers

Cyclotron autoresonance maser (CARM) amplifiers are under investigation as a possible source of high-power (>100 MW), high-frequency (>10 GHz) microwaves for powering the next generation of linear colliders. The authors have completed the design study for a high-power, short pulse, 17.136 GHz CARM amplifier, utilizing a 500 kV linear induction accelerator. A three period bifilar helical wiggler with a wiggle wavelength of 9.21 cm and a field of up to 50 G will be used to spin-up the electron beam. For CARM designs based on induction accelerators, the peak beam powers and beam pulse durations result in the generation of RF pulses which are already well suited to the requirements of future colliders. In addition, a unique feature of CARM amplifiers that use a bifilar helical wiggler to spin-up the electron beam is that the wiggler can be designed so that the phase stability of the CARM is substantially enhanced. Results of the design study, as well as final design parameters, are presented.<>