Advanced X-ray absorption spectroscopy under high pressures at the ESRF beamline ID12

This paper reports on advanced instrumentation for high pressure research developed for the ESRF beamline ID12 which is dedicated to polarization-dependent X-ray absorption spectroscopy at photon energies from 2 to 15 keV. Emphasis is laid on X-ray optics, the design of diamond anvil cell adapted for tender X-ray range and compatible with low temperatures and with high magnetic field as well as a highly efficient X-ray fluorescence detection system. Several examples have been selected to illustrate the performance of the beamline and show what type of advanced spectroscopic techniques can be used to study the local electronic and magnetic properties of materials under pressure.