Measurement of the polarization for soft x-ray magnetic circular dichroism at the BSRF beamline 4B7B

TL;DR

This paper reports the measurement of polarization states of soft x-ray light at BSRF using multilayer mirrors and ellipsometry, enabling the first soft x-ray magnetic circular dichroism measurements at this facility.

Contribution

Introduction of multilayer-based polarization measurement and first soft x-ray magnetic circular dichroism experiments at BSRF.

Findings

Measured linear polarization degree of light at 700-860 eV.

Evaluated circular polarization for the same energy range.

Performed first soft x-ray magnetic circular dichroism measurements at BSRF.

Abstract

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.