IPAC'24 - 15th International Particle Accelerator Conference

High-energy and narrow-bandwidth X-ray regenerative amplifier FEL design for LCLS-II-HE

MOPG54

20 May 2024, 16:00

2h

Bluegrass (MCC Exhibit Hall A)

Poster Presentation MC2.A06 Free Electron Lasers Monday Poster Session

Speaker

Madison Singleton (SLAC National Accelerator Laboratory)

Description

LCLS-II-HE is an energy upgrade of the LCLS-II linac from 4 GeV to 8 GeV. The X-ray FEL photon energy (Self-Amplified Spontaneous Emission mode) will extend towards 12 keV (from the present 5 keV) based on the current beam emittance. To reach higher photon energy range towards 20 keV, a new injector with a much brighter electron beam will be required. Here we study an X-ray regenerative amplifier FEL (XRAFEL) configuration that enables reaching 20 keV photon energy with the current LCLS-II injector parameters, by reamplifying the cavity-returned X-rays in the LCLS-II undulator over multiple passes. At 20 keV, the Bragg mirrors have very narrow angular and wavelength acceptances. In this paper, we discuss how to layout the cavity optics in combination with the electron-beam based Q-switching method to generate fully coherent bright high-energy X-rays with 20 meV spectral bandwidth.