Spatially-Resolved Argon and Neon K-Shell X-Ray Spectra from Triple-Nozzle Gas-Puff Z-Pinches on Cobra*

We present the x-ray spectra obtained during Ar/Ne gas puff z-pinch experiments on the 1MA, 200ns COBRA pulsed power generator at Cornell University. A triple-nozzle gas-puff, which produces two annular (``outer'' and ``inner'') gas puffs and a high density center jet, is used to tailor the radial mass density distribution. Argon and/or neon plasmas are imploded. Filtered x-ray photo-conducting detectors are used for timing the neon and argon K-shell emission and a filtered x-ray pinhole camera images the K-shell x-ray source size. A spectrometer with three spherical mica crystals is used to capture the K-shell x-ray emission. Our objective is to diagnose the Ar and Ne pinch plasma densities (10$^{19}$-10$^{20}$ cm$^{-3}$) and temperatures (0.5 - 2 keV) with 0.1 mm axial and/or radial spatial resolution from the K-shell X-ray spectra. The He-like resonance to intercombination line ratio will be used to estimate the electron density and the He-like resonance to Li-like satellite line ratio will be used to estimate the electron temperature. We will also add Cl as a dopant in either the center Ar gas jet or inner annular puff for K-shell x-ray spectrum studies.