ID20 is dedicated to inelastic hard X-ray scattering (IXS) experiments utilizing hard X-rays. It is optimized for the study of electronic structure of materials. At ID20, we can offer a variety of IXS techniques all of which can be classified into two categories: resonant and non-resonant IXS.

At “resonance”, the incident photon energy is tuned to or scanned across an absorption edge of the material under study: resonant inelastic X-ray scattering (RIXS) and resonant X-ray emission spectroscopy (RXES), including partial fluorescence yield (PFY) X-ray absorption spectroscopy (XAS), fall in this category. Among non-resonant inelastic X-ray scattering (NIXS) techniques, it is worth mentioning X-ray Raman spectroscopy (XRS). All these spectroscopic tools can be used in a large variety of materials ranging from strongly correlated electron systems to liquids and benefit from the specific advantages of a hard X-ray probe, in particular bulk sensitivity and compatibility with complex sample environments.

Scientific Applications

Resonant inelastic X-ray scattering, as all resonant techniques, provide chemical- and site-selective information. RIXS, in particular, allows one to characterize the charge, spin, and orbital degrees of freedom of electrons in the system and, to some extent, also their coupling to the lattice. For example, RIXS was recently employed to probe magnetic, spin-orbit, crystal field and charge-transfer excitations in iridium oxides. Unlike soft RIXS, the use of hard X-rays ensures bulk sensitivity. Moreover, the large momentum transfer available allows studying the dispersion of excitations over a large fraction of the reciprocal space. Concerning the available X-ray absorption edges relevant to resonant spectroscopies, the beamline covers the 4-20 keV energy window which includes, among others, the K edges of 3d transition metals and the L edges of 5d transition metals.

Elementary excitations of the ground state, such as crystal-field transitions or plasmons, can in principle be probed in the non-resonant regime as well, though with different selections rules and cross-sections. However, one of the most appealing application of NIXS is the study of soft X-ray absorption edges in which case the technique is often referred to as X-ray Raman spectroscopy (XRS). Unlike conventional soft XAS, XRS is bulk sensitive and unaffected by self-absorption. Furthermore XRS is not limited to the dipole approximation, and the weight of non-dipolar scattering channels can be tuned by varying the magnitude of the momentum transfer.

Finally, the hard X-rays of ID20 enable us to perform experiments at extreme conditions, i.e. the use of diamond anvil cells for high pressure experiments, or other complex sample environments, e.g. for in-situ and operando studies of batteries, fuel cells, chemical reactors, etc.

For a more detailed introduction to resonant and non-resonant inelastic X-ray scattering techniques, the reader is referred to W. Schülke. Electron dynamics studied by inelastic x-ray scattering - Oxford University Press (2007). More specifically, one can see L. Ament et al., Rev. Mod. Phys. 83, 705, (2011) for RIXS, and  J.-P. Rueff and A. Shukla, Rev. Mod. Phys. 82, 847 (2010) for RXES under high pressure. A comprehensive theoretical introduction to NIXS is instead given in M. W. Haverkort et al., Phys. Rev. Lett. 99, 257401 (2007).

Complementary Information

Tips for Users

You find the deadlines for proposal submission with all necessary information here.

Please do not hesitate to contact us before the submission deadline in case you have questions. In case your proposal is accepted you will receive notice from the user office and shortly after the scheduled dates from the beamline responsible. A beam line staff member will be assigned to you as your local contact for the experiment. It is the responsibility of the users to plan their experiments early in advance and to contact the local contact to discuss the experimental setup.  The local contact has the right expertise to give useful advices and optimize the beamline for your experiment.

Please view the general ESRF guidelines for users: