Ballistic Bunching of Photo-Injected Electron Bunches with Dielectric-Lined Waveguide

TL;DR

This paper presents a passive technique using dielectric-lined waveguides to bunch non-ultrarelativistic electron beams, enabling sub-picosecond bunch trains with high peak currents for advanced accelerator applications.

Contribution

It introduces a simple, passive method to generate ultra-short electron bunches from conventional photoinjectors using dielectric-lined waveguides for energy-to-density modulation conversion.

Findings

Supports generation of sub-picosecond bunch trains

Achieves multi-kA peak currents in electron bunches

Demonstrates a simple technique suitable for compact accelerators

Abstract

We describe a simple technique to passively bunch non-ultrarelativistics ($\lesssim 10$~MeV) 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 sub-picosecond bunch train 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.