Soft X-ray backlighter source driven by a short-pulse laser for pump-probe characterization of warm dense matter.

Here we propose a pump-probe X-ray absorption spectroscopy temperature measurement technique appropriate for matter having temperature in the range of 10 to a few 100 eV and density up to solid density. Atomic modeling simulations indicate that for various low- to mid-Z materials in this range the energy and optical depth of bound-bound and bound-free absorption features are sensitive to temperature. We discuss sample thickness and tamp layer considerations. A series of experimental investigations was carried out using a range of laser parameters with pulse duration ≤5 ps and various pure and alloyed materials to identify backlighter sources suitable for the technique.