  Three ultra-short-period W/B4C multilayers (1.244nm, 1.235nm and 1.034nm)
have been fabricated and used for polarization measurement at the 4B7B Beamline
of Beijing Synchrotron Radiation Facility (BSRF). By rotating analyzer
ellipsometry method, the linear polarization degree of light emerging from this
beamline has been measured and the circular polarization evaluated for
700eV-860eV. The first soft x-ray magnetic circular dichroism measurements are
carried out at BSRF by positioning the beamline aperture out of the plane of
the electron storage ring.
