Compression of sub-relativistic space-charge-dominated electron bunches for single-shot femtosecond electron diffraction

TL;DR

This paper demonstrates the compression of sub-relativistic, space-charge-dominated electron bunches to sub-100 femtoseconds using velocity bunching with a 3 GHz RF cavity, enabling single-shot femtosecond electron diffraction.

Contribution

It introduces a method to compress low-energy electron bunches to femtosecond durations suitable for single-shot diffraction experiments.

Findings

Achieved sub-100 fs electron bunch durations at 95 keV

Captured diffraction pattern with a single shot on gold foil

Measured arrival time jitter of 80 fs

Abstract

We demonstrate compression of 95 keV, space-charge-dominated electron bunches to sub-100 fs durations. These bunches have sufficient charge (200 fC) and are of sufficient quality to capture a diffraction pattern with a single shot, which we demonstrate by a diffraction experiment on a polycrystalline gold foil. Compression is realized by means of velocity bunching as a result of a velocity chirp, induced by the oscillatory longitudinal electric field of a 3 GHz radio-frequency cavity. The arrival time jitter is measured to be 80 fs.