Numerical investigation of a THz-driven dielectric accelerator with a Bragg-reflector for accelerating sub-relativistic electron beams

Structure-based novel accelerators exhibit significant potential for substantial reduction in size and associated costs of future accelerators. Utilizing high-power THz sources in dielectric accelerator structures presents a favorable compromise for achieving elevated gradients and alleviating beam injection requirements. We conducted numerical investigations on an energy-efficient dielectric single grating structure accompanied by a Bragg-reflector, employing THz pulses to generate a phase-modified field for accelerating sub-relativistic electron beams. The structural parameters were optimized to enhance the strength of the acceleration field. The simulation results demonstrate that the side-coupling single grating structure, accompanied by a Bragg-reflector, designed for sub-relativistic electron beam acceleration, can increase the relative structural energy efficiency by more than 50% compared to a dual-grating accelerator structure. Moreover, it offers an available maximum acceleration gradient of up to 400 MeV m −1 .