Diagnostic developments

The ERC Planet Dive project is focused on using X-ray techniques such as X-ray absorption spectroscopy (XANES and EXAFS) and X- ray Diffraction (XRD) on DAC and laser compression experiments. As of today, X-ray structural measurements on matter of geophysical interest have been mostly performed at synchrotron facilities in combination with static compression techniques. XANES has been recently used on laser facility but access to high-energy edge are limited (Benuzzi-Mounaix 2011, Denoued 2014). X-ray absorption spectroscopy and X-ray diffraction are complementary tools to access both the local and long-range atomic order as well as on the electronic structure. Usually performed as stand-alone techniques at synchrotron facilities, simultaneous XRD and XANES measurements call for different experimental setups and impose different constraints on sample dimension and geometry. Addition of XRD is challenging, as the XANES technique imposes relatively small samples thicknesses (few μm), thus reducing the scattering volume. The simultaneous acquisition of both XANES and XRD measurements, only achievable thanks to the unique peak brightness of the FEL beam, would thus be a chief step ahead in the accurate measurements of materials under extreme conditions. Considering the major scientific progress achieved the last decade by the DAC community when accessing X-ray sources such as synchrotrons, investing laser compression on FEL facilities is of a critical and timely importance and will undoubtedly bring similar breakthroughs.

© P. Vacar, LULI

Design of an experimental set-up for ANR IRONFEL