NEH 2.1 RIXS‎ > ‎


  • Spectral Range:  The goal is to provide operation in the range 0.25 – 1.6 keV. This is dictated by the need to cover:
    • the L2,3 edges of the 3d transition metals, where resonant enhancements are particularly strong
    • M2,3 edges of the 4d transition metals
    • K edges of C, N, and O, necessary for studying biological systems
    • the M4,5 edges of the lanthanides
  • Scattering Angle: 
    • In order to maximize the flexibility of experimental scattering geometry, the instrument is designed to cover both backscattering for conventional and time-resolved RIXS experiments, and forward scattering geometries, for stimulated RIXS experiments.  The range of scattering angle is thus specified to be 2θ = (0 - 160) degrees.
  • Spectrometer Resolution: The spectrometer will house two blazed spherical varied-line spacing gratings ruled at different groove density:
    • Very high resolution grating: Target resolving power is 50,000 at 1 keV, matching the resolving power of the beamline monochromator.  This will be achieved using the high diffraction efficiency in 3rd order..
    • Medium resolution grating: Target resolving power ~10,000 at 1 keV, optimized for higher throughput when studying out-of-equilibrium systems.
  • Polarization Analysis: Full polarization analysis of RIXS adds extremely valuable information about the nature of the probed excitations, especially in magnetic systems.  We plan to use multilayer mirrors for the analysis of the scattered x-rays, while control over the polarization state of the incident beam will be provided by the DELTA undulator.
  • X-ray Focusing Capabilities: The beamline re-focusing Kirkpatrick-Baez optics are designed to provide a 1.5 × 20 µm (vertical × horizontal) focus and the position of the focal spot can be changed independently in the horizontal and vertical directions, effectively changing the spot size on the sample mounted at the nominal focusing position.  The focusing conditions are dictated by the requirements to:
    • Place the nominal vertical focus at the center of the RIXS spectrometer
    • Achieve the target overall RP of the spectrometer
    • Maintain the slit-less operation of the spectrometer
    • Maximize flux when studying solid samples