Current advances on Talbot–Lau x-ray imaging diagnostics for high energy density experiments (invited)

作者：M. P. Valdivia, G. Pérez-Callejo, V. Bouffetier, Gilbert Collins, C. Stöeckl, T. Filkins, C. Mileham, M. H. Romanofsky, I. A. Begishev, W. Theobald, Sallee Klein, Manuel K. Schneider, F. N. Beg, A. Casner, D. Stutman · 发表于：Review of Scientific Instruments · 年份：2022 · DOI：10.1063/5.0101865 · 被引用次数：11 · 研究领域：Advanced X-ray Imaging Techniques、Laser-Plasma Interactions and Diagnostics、X-ray Spectroscopy and Fluorescence Analysis

Talbot–Lau x-ray interferometry is a refraction-based diagnostic that can map electron density gradients through phase-contrast methods. The Talbot–Lau x-ray deflectometry (TXD) diagnostics have been deployed in several high energy density experiments. To improve diagnostic performance, a monochromatic TXD was implemented on the Multi-Tera Watt (MTW) laser using 8 keV multilayer mirrors (Δθ/θ = 4.5%-5.6%). Copper foil and wire targets were irradiated at 1014–1015 W/cm2. Laser pulse length (∼10 to 80 ps) and backlighter target configurations were explored in the context of Moiré fringe contrast and spatial resolution. Foil and wire targets delivered increased contrast <30%. The best spatial resolution (<6 μm) was measured for foils irradiated 80° from the surface. Further TXD diagnostic capability enhancement was achieved through the development of advanced data postprocessing tools. The Talbot Interferometry Analysis (TIA) code enabled x-ray refraction measurements from the MTW monochromatic TXD. Additionally, phase, attenuation, and dark-field maps of an ablating x-pinch load were retrieved through TXD. The images show a dense wire core of ∼60 μm diameter surrounded by low-density material of ∼40 μm thickness with an outer diameter ratio of ∼2.3. Attenuation at 8 keV was measured at ∼20% for the dense core and ∼10% for the low-density material. Instrumental and experimental limitations for monochromatic TXD diagnostics are presented. Enhanced postprocessing cap...