Predictive capability for Z-Petawatt-driven high-energy K$\alpha$ x-ray yields used to image HEDP experiments on the Z Machine

The Z-Petawatt laser (ZPW) will provide a high-energy, ultra-short- duration K$_{\alpha}$ x-ray source for imaging HEDP experiments on the Z Machine. Crucial to the best imaging performance is the attainment of the highest possible conversion efficiency ${\epsilon}$ of laser energy into K$_{\alpha}$ x-rays. We test novel target and imaging concepts aimed at dramatically increasing ${\epsilon}$, which, if realized, would be an outstanding benefit to the quality of our experiments on Z. The measured ${\epsilon}$ in recent ZPW experiments was correctly predicted within the experimental uncertainty, and so provides confidence for our established capability to predict high-energy x-ray yield in other, novel target arrangements for increasing ${\epsilon}$. Quality and contrast improvements in high- energy x-ray imaging, whether from traditional or novel sources, are directly beneficial to HEDP experimental platforms such as Z and NIF. \\[4pt] Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. Support provided by the Laboratory Directed Research and Development Program at Sandia.