Single-shot spectrometer using diamond microcrystals for X-ray free-electron laser pulses

Area of Science:

• Physics
• Materials Science
• Optics

Background:

• X-ray free-electron lasers (XFELs) produce high-intensity, tunable X-ray pulses crucial for various scientific experiments.
• Characterizing the spectral properties of these pulses in a single shot is essential for optimizing experimental conditions and understanding laser dynamics.
• Existing methods for spectral analysis may lack the resolution or speed required for single-shot XFEL diagnostics.

Purpose of the Study:

• To develop and demonstrate a simple, high-resolution spectrometer for single-shot spectral diagnosis of XFEL pulses.
• To leverage the unique properties of diamond microcrystals for XFEL spectral analysis.
• To provide a practical tool for routine machine tuning and characterization at XFEL facilities.

Main Methods:

• A spectrometer was designed utilizing diffraction from diamond microcrystals.
• The spectrometer analyzes the powder diffraction profile of XFEL pulses.
• The peak shape of the diffraction pattern is used to determine the spectral characteristics.

Main Results:

• The developed spectrometer achieved a spectral resolution of a few eV.
• The use of large-grain, uniformly latticed diamond microcrystals enabled high-resolution measurements.
• The spectrometer successfully diagnosed single-shot spectra of XFEL pulses.

Conclusions:

• A simple and effective single-shot spectrometer for XFEL pulse diagnosis has been successfully developed.
• Diamond microcrystals are suitable for high-resolution spectral characterization of XFELs.
• The spectrometer is operational and utilized for daily machine tuning at the SACLA beamline 3, demonstrating its practical utility.