Ballistic bunching of photoinjected electron bunches with dielectric-lined waveguides

Abstract

We describe a simple technique to passively bunch non-ultra-relativistic (≲10MeV) electron bunches produced in conventional photoinjectors. The scheme employs a dielectric-lined waveguide located downstream of the electron source to impress an energy modulation on a picosecond bunch. The energy modulation is then converted into a density modulation via ballistic bunching. The method is shown to support the generation of subpicosecond bunch trains with multi-kA peak currents. The relatively simple technique is expected to find applications in compact, accelerator-based, light sources and advanced beam-driven accelerator methods.