Pump-probe reciprocal-space mapping using energy-resolved XFEL pink beam pulses.

Area of Science:

• Materials Science
• X-ray Physics
• Solid State Physics

Background:

• Reciprocal-space mapping (RSM) is crucial for characterizing crystalline materials.
• Traditional RSM methods often face limitations in energy resolution and data acquisition speed.
• X-ray free-electron lasers (XFELs) offer high peak brilliance but their inherent energy bandwidth (pink beam) poses challenges for precise measurements.

Purpose of the Study:

• To develop a novel 3D RSM method capable of utilizing the broad energy bandwidth of pink XFEL beams.
• To enable high-resolution 3D reciprocal space characterization of materials, including dynamic processes.
• To overcome the limitations of conventional RSM techniques in capturing complex scattering phenomena.

Main Methods:

• Utilizing a pink self-amplified spontaneous emission (SASE) X-ray free-electron laser beam.
• Employing a pump-probe X-ray diffraction setup.
• Reconstructing a thin slab of RSM corresponding to the pink beam's energy bandwidth.
• Rocking the sample in discrete steps to cover the desired reciprocal space volume.

Main Results:

• Successfully reconstructed a 3D RSM using a pink SASE XFEL beam.
• Demonstrated the ability to determine the energy of individual pulses within the SASE beam using the sample's diffraction pattern as a reference.
• Obtained comprehensive 3D RSM data, including diffuse scattering and Bragg rods, from NiO thin films.

Conclusions:

• The proposed 3D RSM method effectively leverages pink XFEL beams for advanced materials characterization.
• This technique allows for detailed analysis of both static and dynamic scattering features in crystalline thin films.
• The method opens new avenues for studying complex material structures and phase transitions with high resolution.