Polarization measurements in the VUV region of synchrotron radiation

The polarization characteristics of the VUV light emerging from the 5 m normal incidence monochromator at the Daresbury Synchrotron Radiation Source, UK, have been investigated. The results show that the linear polarization changes with photon energy, that the major polarization axis is inclined with respect to the horizontal direction and that the degree of inclination also changes with photon energy. Using Stokes' parameters and Mueller matrices, these results are explained by the influence of the beamline optics on the radiation. The results should be relevant to VUV beamlines at other synchrotron radiation sources. The design and construction of the polarizer used are described.