Higher Order Suppressor (HOS) for the PolLux Microspectroscope Beamline at the Swiss Light Source SLS

The mechanical design and performance of a device to suppress higher orders of a spherical grating monochromator at a constant deviation angle is described. The higher order suppressor (HOS) is used for a scanning transmission x-ray microspectroscope beamline (PolLux) at a bending magnet of the Swiss Light Source (SLS). The instruments allow microspectroscopy in polymer science, of biological samples in the water window as well as the study of magnetic materials with circular or linear polarized light in a photon energy range of 200 eV to 1400 eV. The HOS uses three mirrors acting as a low pass filter for soft x-rays to improve the absorption spectroscopy of carbon, oxygen and nitrogen 1s core levels. The successful installation and operation of the HOS located after the monochromator is reported. First results obtained using samples from materials research and environmental sciences exemplify the improved spectroscopy capabilities of the instrument.