Electron Pulse Compression With a Practical Reflectron Design for Ultrafast Electron Diffraction

Ultrafast electron diffraction (UED) is a powerful method for studying time-resolved structural changes. Currently, space-charge-induced temporal broadening prevents obtaining high-brightness electron pulses with sub-100 fs durations limiting the range of phenomena that can be studied with this technique. We review the state of the art of UED in this respect and propose a practical design for reflectron-based pulse compression that utilizes only electrostatic optics and has a tunable temporal focal point. Our simulation shows that this scheme is capable of compressing an electron pulse containing 100 000 electrons with 60:1 temporal compression ratio.