An x-ray backlit Talbot-Lau deflectometer for high-energy-density electron density diagnostics

Area of Science:

• Plasma physics
• X-ray optics
• High-energy-density science

Background:

• X-ray phase-contrast imaging offers enhanced sensitivity to electron density gradients compared to conventional radiography.
• High-energy X-rays are crucial for probing dense plasmas generated by intense laser systems.

Purpose of the Study:

• To demonstrate the capability of X-ray phase-contrast imaging using a Talbot-Lau interferometer for diagnosing high-energy-density plasmas.
• To measure electron density gradients and profiles in laser-produced plasmas.

Main Methods:

• Utilized an 8 keV Talbot-Lau interferometer with free-standing ultrathin gratings.
• Employed K-shell emission from copper foil targets irradiated by 1-30 J, 8 ps laser pulses.
• Performed X-ray deflectometry with laser backlighting.

Main Results:

• Achieved grating survival under high-intensity 30 J, 8 ps laser pulses.
• Obtained X-ray deflectometry images with up to 25% contrast.
• Detected electron areal density gradients up to 8.1 ± 0.5 × 10^23 cm^-3 in a low-Z sample.
• Reconstructed electron density profiles with <8% error.
• Achieved 50 ± 15 μm spatial resolution.

Conclusions:

• X-ray phase-contrast imaging is a viable diagnostic for high-energy-density plasmas.
• The Talbot-Lau interferometer demonstrated robustness and effectiveness in this challenging environment.
• The technique provides quantitative measurements of plasma density gradients and profiles.