Development of Talbot-Lau phase-contrast method for high energy density plasma diagnostics

Phase-contrast x-ray imaging techniques can detect density gradients in low-Z matter with the sensitivity and spatial resolution necessary to characterize High Energy Density Laboratory Plasma (HEDLP) experiments. The Talbot-Lau interferometer measures x-ray beam angular deviations due to refraction index gradients along its path, thus making it an attractive plasma diagnostic. The Talbot-Lau interferometer can simultaneously provide x-ray attenuation, refraction, and scatter images which may offer a simple diagnostic for micro instabilities. We extend the Talbot-Lau method used for medical applications to lower x-ray energies, high magnification and high spatial resolution HEDLP experiments require. We study and develop single image based phase-retrieval techniques. The experimental and simulated results obtained show a clear advantage of the Talbot-Lau Moiré technique over the attenuation and propagation methods. The Moiré technique can detect both sharp and smooth density gradients, using extended, polychromatic, incoherent, line and continuum x-ray sources, thus allowing for less demanding backlighters than those typically used in HEDLP radiography.