Optimized x-ray sources for x-ray diffraction measurements at the Omega Laser Facility

Area of Science:

• Plasma physics
• Materials science under extreme conditions
• High-energy-density physics

Background:

• X-ray diffraction (XRD) is vital for studying materials under extreme conditions.
• Laser-driven dynamic compression experiments utilize XRD for in situ analysis.
• X-ray sources for these experiments are generated by irradiating solid foils, often producing quasimonochromatic He-α radiation.

Purpose of the Study:

• To investigate the dependence of X-ray source spectra on laser drive conditions.
• To analyze the monochromaticity of He-α radiation from laser-irradiated copper, germanium, and iron foils.
• To discuss the implications of these findings for X-ray diffraction experiments.

Main Methods:

• Laser irradiation of copper, germanium, and iron foils at the Omega Laser facility.
• Analysis of emitted X-ray source plasma spectra.
• Varying laser drive conditions to observe spectral changes.

Main Results:

• The quasimonochromatic He-α radiation is not a single line emission.
• The monochromaticity of the X-ray source is highly dependent on laser irradiance.
• Spectral variations were observed for different materials (Cu, Ge, Fe) and laser drive conditions.

Conclusions:

• Understanding the X-ray source spectral characteristics is critical for accurate XRD measurements.
• Laser drive conditions must be carefully controlled to optimize X-ray source monochromaticity for XRD.
• This research provides insights into optimizing X-ray sources for dynamic compression experiments.