Wire, Hybrid, and Laser-Cut X-Pinch Emission Studies for Talbot-Lau X-Ray Deflectometry

Abstract

Talbot-Lau X-ray Deflectometry (TXD) is a refraction-based imaging diagnostic that enables plasma electron density mapping through Moire imaging. TXD has been studied and developed with the goal of diagnosing high energy density plasmas and the adaptation of pulsed-power systems is presented. X-pinches are well-known for generating fast (~1 ns), small (~1 µm) X-ray sources. Three distinct copper x- pinch configurations were driven on the compact Linear Transformer Driver GenASIS (~200 kA, 150 ns). Wire, hybrid, and laser-cut x-pinches were studied as potential backlighter sources for TXD. X-ray emission from each configuration was analyzed in context of x-ray backlighter requirements for the TXD systems implemented. Spatial and temporal resolution, number of sources, time of emission, spectrum, and reproducibility were characterized through a suit of diagnostics. Results and analysis of x-ray emission from wire, hybrid, and laser-cut x-pinch configurations are presented along with recommendations for future experimental improvements and applications. Electron density of static objects was retrieved from Moire images. Mass density was retrieved with 11% error for hybrid x- pinches and 4% for laser-cut x-pinches. Laser-cut x-pinches were found to be the optimal x-pinch configuration for TXD due to their high reproducibility, small source size (≤ 5 µm), short duration (~1 ns FWHM), and up to 10 6 W peak power at ~8 keV, matching the Talbot-Lau interferometer design energy. Plasma loads were imaged through TXD for the first- time using laser-cut x-pinch backlighting. Experimental images agreed well with X-ray Wave-Front Propagation simulations, demonstrating that TXD can be a powerful x-ray refraction-based diagnostic for dense Z-pinch loads.