The Talbot-Lau x-ray deflectometer: a refraction-based electron density diagnostic for High Energy Density experiments

Talbot-Lau X-ray Deflectometry (TXD) has been developed as an electron density diagnostic for High Energy Density (HED) plasmas. The diagnostic delivers refraction, attenuation, elemental composition, and scatter information from a single-shot Moiré image. A Talbot-Lau interferometer has been benchmarked using laser-target and X-pinch x-ray backlighters. Grating survival and electron density mapping were demonstrated for: a) 25–29 J, 8–30 ps laser pulses using Cu targets and b) a 4 x 25 µm copper X-pinch driven by a ~350kA/350ns generator. X-ray backlighter quality was assessed in order to optimize areal electron density gradient retrieval and electron density mapping. TXD enabled accurate areal electron density detection with high contrast (>25%) and spatial resolution of ~50 µm in the high-power laser experiments, while lower contrast (<15%) and a higher spatial resolution of <27 µm were found in pulsed power experiments, demonstrating the potential of TXD as an electron density diagnostic for HED plasmas.