Analysis of the circular polarization rate delivered by an asymmetric wiggler and a two beryl crystal monochromator—Calculation and experiment

Synchrotrons are powerful sources of an x-ray beam whose polarization state is well defined. The recent apparition of insertion devices able to produce high flux of circularly polarized light has impulsed new fields of solid-state physics in spectroscopy or diffraction techniques. In this paper, the calculation of circular polarization rates taking into account the characteristics of the synchrotron source and the depolarization effect introduced by the beam monochromatization on crystals is presented here. From measurements of the circular polarization rates by x-ray magnetic circular dichroism at nickel L2,3 edges, the experimental results are in excellent agreement with the calculations.