Single-Shot Multi-keV X-Ray Absorption Spectroscopy Using an Ultrashort Laser-Wakefield Accelerator Source

Area of Science:

• Physics
• Materials Science
• Plasma Physics

Background:

• Laser-wakefield accelerators (LWFA) generate high-energy electron beams.
• Betatron radiation from LWFA can produce X-rays for diagnostics.
• Ultrafast processes in matter require high-resolution, time-resolved measurements.

Purpose of the Study:

• To perform single-shot X-ray absorption near-edge structure (XANES) measurements.
• To characterize X-ray sources generated by LWFA for absorption spectroscopy.
• To demonstrate simultaneous electron and ion distribution measurements in laser-heated matter.

Main Methods:

• Utilizing a 200 TW laser to drive an LWFA, producing broadband electron beams (>1 GeV).
• Generating multi-keV X-rays via betatron oscillations with high photon flux (1.2e6 photons/eV) and signal-to-noise ratio (~300:1).
• Conducting single-shot XANES measurements on a titanium K edge and comparing with density functional theory (DFT) simulations.

Main Results:

• Achieved high-resolution, single-shot XANES measurements at the titanium K edge.
• Demonstrated the capability for simultaneous measurement of electron and ion distributions in eV-temperature matter.
• Validated the LWFA-generated X-ray source for ultrafast material analysis.

Conclusions:

• LWFA-generated X-rays are suitable for single-shot XANES spectroscopy.
• The synchronized X-ray source enables advanced studies of ultrafast energetic processes.
• This technology facilitates breakthroughs in understanding electron-ion equilibration in materials.