At-wavelength characterization of X-ray wavefronts in Bragg diffraction from crystals.

Area of Science:

• Materials Science
• Optics
• Physics

Background:

• Next-generation synchrotron radiation sources and X-ray free-electron lasers (XFELs) demand high-quality Bragg-diffraction crystal optics.
• Preserving X-ray beam coherence and wavefront is critical for these advanced sources.
• Characterizing crystal optics for Bragg-plane height errors and wavefront distortions presents significant challenges.

Purpose of the Study:

• To propose and validate a quantitative methodology for characterizing crystal optics.
• To assess Bragg-plane height errors and wavefront phase distortions.
• To meet the stringent requirements of advanced X-ray applications.

Main Methods:

• Utilized a state-of-the-art at-wavelength wavefront sensing technique.
• Employed statistical analysis for quantitative characterization.
• Tested the method at the 1-BM-B optics testing beamline at the Advanced Photon Source.
• Performed measurements in self-referencing single-crystal and absolute double-crystal modes.

Main Results:

• Successfully characterized silicon and diamond crystals.
• Demonstrated phase error sensitivity at the λ/100 level.
• Validated the technique for demanding applications.

Conclusions:

• The proposed methodology effectively characterizes crystal optics for advanced X-ray applications.
• The technique's sensitivity meets the requirements for applications like cavity-based XFELs.
• This work provides a crucial tool for developing high-performance X-ray optics.