X-ray absorption spectroscopy of laser-produced plasmas: A study of the experiment and data analysis

The novel technique of point-projection backlighting is used to probe alaser-produced plasma. A spatially restricted source of x rays is created byirradiating a fiber which is used to backlight a plasma. Temporal resolution ofthe absorption spectrum is obtained by creating the backlight with a pulse thatis delayed in time from the main, plasma-producing, laser. The backlight canalso be of shorter duration than the main laser pulse providing for enhancedtime resolution and therefore less temporal averaging. The results forlow-/ital Z/ aluminum and silicon targets are presented. The low-/ital Z/absorption spectra using both low-/ital Z/ (e.g., aluminum) and high-/ital Z/(e.g., molybdenum) elements for backlighting are studied. A description of thistechnique and the analysis of the data obtained is presented.