MEDSI2025 - 13th International Conference on Mechanical Engineering Design of Synchrotron Radiation Equipment and Instrumentation

Ultra-high-resolution monochromators for XFEL applications at LCLS-II-HE: a 4f Optical approach with channel-cut crystals

TUP61

16 Sept 2025, 17:00

1h 15m

Poster Session Room (The Loop)

Poster Presentation Beamlines and Instruments Poster Session 1

Speaker

Hengzi Wang (SLAC National Accelerator Laboratory)

Description

Traditional synchrotron monochromators cannot handle the extreme thermal loads and stability demands of XFELs, especially for seeded X-rays. To overcome this, LCLS-II-HE has developed a multi-stage monochromator system integrating two double channel-cut (DCCMs) and two consecutive channel-cut monochromators (CCMs) in a 4f optical configuration. This ensures precise beam collimation, spectral filtering, and wavefront preservation while achieving ultra-high energy resolution. Asymmetrically cut silicon crystals distribute thermal loads over a larger beam footprint, reducing distortions and enhancing stability—critical for RIXS experiments probing low-energy excitations in quantum materials. The 4f alignment minimizes spectral drift and enhances reproducibility, ensuring the sensitivity needed for resolving subtle electronic and phononic interactions. This presentation details the design, implementation, and impact of this system, providing a scalable solution for next-generation RIXS studies at LCLS.

Funding Agency

Funding for this research is provided by: the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Contract No. DE-AC02-76SF00515