Single-shot Dispersive X-ray Absorption Fine Structure Spectroscopy Using an X-pinch X-ray Source

The energy-dispersive x-ray absorption fine structure spectroscopy (EDXAFS) allows simultaneous measurement of density, ion temperature, and geometric structure of dense samples. Simultanously, the slope of an absorption edge allows the measurement of electronic temperature. These measurements are especially applicable to strongly coupled and optically opaque states of matter produced in laser-driven dynamic compression and x-ray radiatively driven experiments which are inaccessible to optical methods such as Thompson scattering. Dry Pinch I, a portable X-pinch developed at Imperial College, can produce on-sample photon flux of >10000 photons / eV around the Aluminium K edge within a single ~1 ns long x-ray burst. The X-pinch has a smooth and continuous spectrum enabling EDXAFS measurements. Using a spherical crystal, we measure a spectral bandwidth of 100 eV around the Aluminium K edge at 1559 eV (sufficient for near-edge structure measurements). As a proof-of-concept, we used the X-pinch to successfully measure the near-edge spectrum of a 2 micrometer thick aluminium foil in a single-shot mode. An experiment on the XP facility at Cornell will extend this measurement technique to higher energies, improve the integrated signal, and enable experiments with current heated samples.