Full polarization measurement of SR emitted from twin helical undulators with use of Sc/Cr multilayers at near 400 eV

Abstract

We carried out the full polarization measurements on highly circularly polarized light in soft X-ray region. The measurements were performed on synchrotron radiation of near 400 eV emitted from twin helical undulators at BL25SU in the SPring-8. All parameters of polarization state of the light were determined with a phase shifting transmission multilayer and a polarizing reflection multilayer. The phase shifter was a newly developed Sc/Cr multilayer and was evaluated as a quarter-wave plate. The results of full polarization measurement indicated that the twin undulators produced symmetrically circularly polarized light.