Active Q-switched X-Ray Regenerative Amplifier Free-Electron Laser

TL;DR

This paper proposes an active Q-switched x-ray regenerative amplifier FEL scheme that can produce fully coherent, high-brightness hard x-rays at high repetition rates, with controllable cavity quality and demonstrated through theoretical and numerical analysis.

Contribution

It introduces a novel active Q-switched FEL scheme with simple electron-beam phase space manipulation for improved control and coherence of x-ray output.

Findings

The scheme can produce fully coherent, high-brightness x-rays.

The cavity quality factor Q can be actively controlled.

Theoretical and numerical studies validate the scheme's feasibility.

Abstract

Despite tremendous progress in x-ray free-electron laser (FEL) science over the last decade, future applications still demand fully coherent, stable x-rays that have not been demonstrated in existing X-ray FEL facilities. In this Letter, we describe an active Q-switched x-ray regenerative amplifier FEL scheme to produce fully coherent, high-brightness, hard x rays at a high-repetition rate. By using simple electron-beam phase space manipulation, we show this scheme is flexible in controlling the x-ray cavity quality factor Q and hence the output radiation. We report both theoretical and numerical studies on this scheme with a wide range of accelerator, x-ray cavity, and undulator parameters.