Porträt Dr. habil. Scheinost, Andreas; FWOS

Dr. habil. Andreas Scheinost

Molecular Structures

Phone: +33 476 88 2462
+33 6 340 358 18

Jana Gorzitze

Institute of Resource Ecology
Phone: +49 351 260 3233

Restart News
October 18, 2019
Upgrade proceeds as planned, restart expected in September 2020!


Beamline Optics

  • The X-ray optics provide both a high flux at high angular resolution for diffraction and a high flux over a wide energy range with high energy resolution for EXAFS spectroscopy.
  • A complete update of the optics have been performed in 2011-2012 with a major investment of 2 Mio EUR.
  • The key points of this upgrade are:
    • Higher flux by horizontal focusing: Double toroid focusing mirror
    • Higher flux by wider energy bandgap: double multilayer monochromator
    • Improved energy resolution and glitch management: Si(111)/Si(111)90/Si(311)
    • Faster spectroscopy:  Quick-XAS-suited monochromator
    • Wider energy coverage: mirrors with Si, Rh and Pt surfaces
    • Faster beamline adjustment: beam diagnostics after each optical element
    • More stable beam: active beam position control
    • LN2 cooling
ROBL optics scheme with raytracing ©Copyright: Dr. habil. Scheinost, Andreas
Schematic view of the beamline optics, showing the bending magnetic at the right, the first white-beam mirror, the DCM, and the second monochromatic-beam mirror. Shown are also typical beam profiles and photon fluxes for the unfocussed beam at the XAFS station, and for the focussed beam at teh XRD-1 station.
Schema DCM/DMM

A unique monochromator, which combines both a double crystal pair (in fact three pairs: Si(111), Si(111)30º, Si(311)) for high energy resolution, and a double multilayer monochromator for high flux with medium energy resolution (∼100 eV).

Mirror reflectivity

The Optics contain two long mirrors; the first, with Rh, Si and Pt surfaces, is water-cooled and collimates the beam into the monochromator to improve the energy resolution;  the second after the monochromator has two torroidal-shaped sections coated with Rh and Pt to focus the monochromatic beam vertically and horizontally, in addition to a flat Si section. Both mirrors serve also for the rejection of higher harmonics. The figure above shows the reflectivity of the different mirror surfaces at a grazing angle of 2.5 mrad.