Neon photoionization experiments driven by Z-pinch radiation

Abstract

Present-day Z-pinch experiments generate ∼2 x 1021 erg/s peak power, ∼6 ns full-width at half-maximum X-ray bursts that provide new possibilities to study radiation-heated matter. This source is being used to investigate the production of plasmas in which photoionization dominates collisional ionization. Spectroscopic measurements of such plasmas can serve to benchmark atomic physics models of the photoionized plasmas. Beyond intrinsic interest in the atomic physics, these models will be applied to the interpretation of data from the new generation of satellite X-ray spectrographs that will promote the understanding of accretion-powered objects such as X-ray binaries and active galactic nuclei. Moreover, this information is needed for X-ray laser research. Our experiments use a 1-cm-scale neon gas cell to expose 1018 atoms/cm3 to an X-ray flux of ∼5 x 1018 erg/cm2/s. Thin mylar (1.5 μm) windows confine the gas and allow the radiation to flow into the cell. The ionization is monitored with absorption spectra recorded with crystal spectrometers, using the pinch as a backlight source. In initial experiments we acquired an absorption spectrum from Li- and He-like Ne, confirming the ability to produce a highly ionized neon plasma. © 2001 Elsevier Science Ltd. All rights reserved.