Broadband-To-Monochromatic X-ray conversion of Zr K$_{\alpha,\beta}$ Lines and High-Energy-Density (HED) Plasma Diagnostics

Experimental and theoretical studies of the formation of K$_{\alpha}$, K$_{\beta}$ X-ray complexes from high-Z elements are of interest in diverse areas such as HED plasma sources and biomedical applications. Conversion of bremsstrahlung-to-monochromatic (B2M) X-ray K$_{\alpha}$, K$_{\beta}$ lines is studied using a broadband 150 KV X-ray generator and a solid Zirconium target. We carried out Breit-Pauli atomic structure calculations for all possible fine-structure components of transition arrays leading to the formation of K$_{\alpha}$ and K$_{\alpha}$ complexes in H- to F-like Zr (Z=40), and other high-Z elements up to platinum and gold (Z=78,79) [1,2]. Fine structure averaged energies and cross sections for K$_{\alpha}$ and K$_{\beta}$ resonances in each ionization state of Zr are presented. Such K$_{\alpha}$ resonances [1,2] have been observed in X-ray laser produced warm dense matter at the LCLS-XFEL at SLAC [3]. Numerical simulations using the code FLYCHK indicate temperature and density sensitivities in laser-irradiated plasmas.\\[4pt] [1] Pradhan et al, J. Phys. Chem. A \textbf{113}, 12356 (2009)\\[0pt] [2] Nahar et al, Can. J. Phys. 89, 483 (2011); Nahar \& Pradhan (2014)\\[0pt] [3] S. M. Vinko et al, Nature \textbf{482}, 59 (2012).