Techniques for soft x-ray absorption in laser-produced plasmas

Interest in x-ray absorption derives from soft x-ray transport studies to characterize laser-solid-interaction effects. The object of this work was to determine whether x-ray absorption features were measurable in laser-produced plasmas from solid targets. X-ray emission was made using high-atomic-number microsphere targets irradiated with a focused beam of the Pharos laser while the laser-solid-interaction plasmas were generated by a second beam in Al foil targets. High-resolution, spatially resolved x-ray spectra were collected with instrumentation and geometry similar to previous tracer-dot spectroscopy measurements of plasma profile parameters. Soft x-ray absorption lines, observed at different distances from the aluminum target surface, may be related to density gradients in the laser-generated plasmas.