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J.E. Bailey (Sandia National Laboratories), D. Cohen (Swarthmore College), G.A. Chandler, M.E. Cuneo, T.J. Nash, W.A. Stygar (Sandia National Laboratories), J.J. MacFarlane (Prism Computational Science), D. Jobe, P. Lake, D. Nielson, R. Smelser (K-Tech Corporation), M.E. Foord, R.F. Heeter, D.A. Liedahl (Lawrence Livermore National Laboratories)
Present-day Z-pinch experiments generate 2 x 1021 erg/s, 5 nsec duration x-ray bursts that provide new possibilities to study radiation-heated matter. We are using this source to investigate plasmas in which photoionization dominates collisional ionization. Spectroscopic measurements of such plasmas can serve to benchmark photoionized-plasma atomic physics models that will be used to interpret data from the new generation of x-ray satellite spectrographs. This should be useful for understanding accretion-powered objects such as X-ray binaries and active galactic nuclei. These objects are frequently observed, but the interpretation of their spectra is difficult: state-of-the-art models for photoionized plasmas do not always agree on the expected ionization distribution. Our experiments use a 1-cm-scale gas cell to expose various gases to an x-ray flux of approximately 3 x 1019 erg/s/cm2. Thin mylar (1.5 micron) windows allow the radiation to flow into the cell. The ionization is monitored using emission and absorption spectroscopy. In initial experiments we acquired an absorption spectrum from Li- and He-like Ne. Analysis of the measurements and comparison with computer simulations are in progress.
Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy under contract DE-AC04-94AL85000