A tunable plasma-based energy dechirper

TL;DR

This paper demonstrates a plasma-based dechirper that effectively reduces energy spread in high-energy electron beams, outperforming existing methods and promising for future accelerator applications.

Contribution

It introduces a tunable plasma-based dechirper that significantly exceeds current state-of-the-art techniques in dechirping strength.

Findings

Reduced energy spread from 1.31% to 0.33%

Good agreement with analytic and simulation predictions

Dechirping strength of 1.8 GeV/mm/m

Abstract

A tunable plasma-based energy dechirper has been developed at FLASHForward to remove the correlated energy spread of a 681~MeV electron bunch. Through the interaction of the bunch with wakefields excited in plasma the projected energy spread was reduced from a FWHM of 1.31$\%$ to 0.33$\%$ without reducing the stability of the incoming beam. The experimental results for variable plasma density are in good agreement with analytic predictions and three-dimensional simulations. The proof-of-principle dechirping strength of $1.8$~GeV/mm/m significantly exceeds those demonstrated for competing state-of-the-art techniques and may be key to future plasma wakefield-based free-electron lasers and high energy physics facilities, where large intrinsic chirps need to be removed.