Efficient high order suppression system for a metrology beamline

High quality metrology with synchrotron radiation requires in particular a very high spectral purity of the incident beam. This is usually achieved by a set of transmission filters with suitable absorption edges to suppress high order radiation of the monochromator. The at wavelength metrology station at a BESSY II bending magnet collimated plane grating monochromator c PGM beamline has recently commissioned a high order suppression system HiOS based on four reflections from mirrors which can be inserted into the beam path. Two pairs of mirrors are aligned parallel so as not to disturb the original beam path and are rotated clockwise and counter clockwise. Three sets of coatings are available for the different energy ranges and the incidence angle is freely tunable to find the optimum figure of merit for maximum suppression at maximum transmission for each photon energy required. Measured perfor mance results of the HiOS for the EUV and XUV range are compared with simulations, and applications are discusse