Extended x-ray absorption fine-structure experiments with a laser-imploded target as a radiation source

Abstract

The feasibility of using extended x-ray absorption fine structure (EXAFS) for characterizing metals shocked to megabar (1 bar = 0.1 MPa) pressures by a laser has been studied. High-contrast K-edge modulations for an unshocked Ti-foil absorber were obtained with a laser-imploded spherical target as a source. The high intensity and relative smoothness of the source spectrum enable us to work with thick Ti foils, which increases the relative modulation in the measured signal. Using a semiempirical model to describe the shock-compressed foil, we show that, because of the rise in Debye temperature with density, the compression extends the temperature range at which EXAFS modulations can be observed.