An apparatus for the characterization of warm, dense deuterium with inelastic x-ray scattering

We present an instrument platform for studying shock-compressed deuterium on moderately sized laser facilities. The target is designed for cryogenic liquid deuterium to be compressed with a sub-kJ laser pulse. The x-ray probe is the narrow band 2005 eV Si Ly-α resonance produced by a 200 J laser incident on a Si3N4 foil. Scattered x-ray collection occurs in the backward and forward directions; spectral dispersion with Bragg crystals yields the plasma conditions of density and temperature. Additionally, the shock is probed with velocity interferometry. Combined with the electron density measurements from forward scattering, this allows average ionization state to be inferred. Proof of principle experiments demonstrate the viability of this technique for studies of the ionization of deuterium along the Hugoniot.