HE-SGM

HE-SGM for NEXAFS/XPS spectroscopy

The HE-SGM beamline is a dipole beamline optimized for NEXAFS spectroscopy in the VUV range. It is designed to cover the light element (C, N, O and F) K-edges which contain important spectroscopic information about soft matter samples, carbon (nano) materials and molecules adsorbed on catalytically relevant surfaces. Oxygen plasma treatment of optical elements in the beamline removed carbon contamination from their surfaces resulting in crucial decrease of parasitic contributions to the experimental data. The beamline monochromator allows for fast scanning over the energy range (155 - 750 eV).

Optical layout of the HE-SGM beamline

Fig.1 HE-SGM Beamline

Fig.2 Optical lay-out and measured performance data

Fig.3 Dependence of the direct beam intensity on the photon energy (transmission function) around C K-edge.

The HE-SGM beamline is a dipole beamline optimized for NEXAFS spectroscopy in the VUV range. It is designed to cover the light element (C, N, O and F) K-edges which contain important spectroscopic information about soft matter samples, carbon (nano) materials and molecules adsorbed on catalytically relevant surfaces. The beamline monochromator allows for fast scanning over the energy ranges of interest (155 eV - 750 eV). There are a number of similar beamlines at other synchrotron facilities worldwide. With regard to the spectroscopic parameters, the HE-SGM beamline is considered to be in the top three of comparable dipole beamlines. The optical elements of the beamline (mirror, monochromator) were additionally cleaned with oxygen plasma to remove carbon contamination from their surfaces resulting in crucial decrease of parasitic contributions to the experimental data (Fig. 3). Such uniqueness allows to acquire proper experimental data for organic molecular thin films with a thickness down to 0.1 monolayer. During reinstallation of the beamline, the adjustment of the entrance slit was improved resulting in a better polarization factor - which increased to 91%.