The Use of Microwave Superradiance Pulses for High-Gradient Acceleration of Electrons in a Cylindrical Waveguide with a Dielectric Insert

This letter presents a theoretical study of the acceleration of an electron by a 38-GHz subnanosecond superradiance pulse with a 3-GW peak power in a cylindrical waveguide with a tubular dielectric insert. It is shown that the energy gain and the accelerating gradient depend on the permittivity of the insert. In this case, the energy gain decreases and the gradient increases with increasing permittivity. For an electron with an initial energy of 300 keV, the maximum accelerating gradient reaches 120 MV/m with an energy gain of 7.2 MeV in a waveguide with a polystyrene insert ( ε = 2.53) and 220 MV/m with an energy gain of 4.5 MeV in a waveguide with a quartz insert ( ε = 3.81).