X-ray crystal spectrometer for opacity measurements in the 8-18 Å spectral range at the LULI laser facility

An x-ray crystal spectrometer was built in order to measure opacities in the 8-18 angstrom spectral range with an average spectral resolution of <lambda/delta lambda >similar to 400. It has been successfully used at the LULI-2000 laser facility (See C. Sauteret, rapport LULI 2001, 88 (2002) at Ecole Polytechnique (France) to measure in the same experimental conditions the 2p-3d transitions of several elements with the neighboring atomic number Z: Fe, Ni, Cu, and Ge [G. Loisel et al., High Energy Density Phys. 5, 173 (2009)]. Hence, a spectrometer with a wide spectral range is needed. This spectrometer features two lines of sight. In this example, one line of sight looks through the sample and the other one is looking directly at the backlighter emission. Both are outfitted with a spherical condensing mirror. A TlAP crystal is used for spectral dispersion. Detection is made with an image plate Fuji BAS TR2025, which is sensitive to x rays. We present some experimental results showing the performances of this spectrometer. (C) 2010 American Institute of Physics. [doi:10.1063/1.3491285]