Acceleration of Electrons by Subnanosecond Superradiant Pulses: Modeling and Experiments

On the basis of numerical simulations, we develop an experimental scheme for high-gradient acceleration of electrons by Ka-band GW-level sub-nanosecond pulses of microwave superradiance (SR). The scheme represents a “generator-accelerator” unit, combined in one vacuum volume and powered by two coaxial electron beams. The SR pulse, generated by the external beam, pumps the “pill-box” resonator where the internal test beam is accelerated. The electron energy was determined based on measurements of the internal beam current after it passed through aluminum filters (foils) of various thicknesses. We have been experimentally demonstrated the increase in electron energy above 1 MeV at an acceleration gradient of 250 MV/m. The obtained gradient value significantly exceeds the record parameters achieved on the basis of long-wavelength klystrons.