Development of compact source of multi-MeV electrons accelerated by W-band superradiant pulses

In this paper, we propose a concept for a compact high-gradient electron accelerator based on the use of 90 GHz, 800 ps microwave pulses generated by a relativistic super-radiant surface-wave oscillator. A 32-cell π-mode standing-wave accelerating structure is designed. This structure has a distributed power-feeding system, with input waveguides coupled to every second cell. A compact waveguide system is simulated that divides input power into 16 channels and ensures appropriate time delays at the cells' input couplers. At an input pulse power of 160 MW, the maximum electric field on the structure surface is 530 MV/m, which, according to previous Ka-band experiments, can be achieved without breakdown for subnanosecond field exposure. In simulations, electron energy increases from 3 to 12 MeV at a distance of 48 mm, corresponding to an acceleration gradient of about 370 MV/m and an averaged energy gain rate of 190 MeV/m. These values significantly exceed values achievable for conventional structures powered by long-pulse klystrons.