北京同步辐射软X射线偏振测量装置及其应用

The soft X-ray polarimeter and applications at BSRF

在北京同步辐射装置(BSRF)设计建造了一套基于多层膜偏振元件的软X射线偏振测量分析装置,可工作在双反、双透、前反后透和前透后反四种工作模式,既可作为偏振测量装置,用于同步辐射光束线和多层膜偏振元件偏振特性测量,也可作为通用反射率计,用于多层膜和薄膜的反射或透射率测量,又可用于磁性材料的磁光效应研究等。利用自行研制的装置和光学元件对BSRF的3W1B光束线的偏振特性进行了系统的测量。测量结果指出,在206 eV时,输出光的线偏振度从起偏前的0.585上升到起偏后的0.995,同步光的线偏振度得到极大改善。利用非周期宽带Mo/Si多层膜开展了铁磁性材料的磁光法拉第效应测量,获得了Ni薄膜3p边附近(60–70 eV)的法拉第旋转角度,最大偏转角度在65.5 eV和68 eV分别为1.85±0.19°和–0.75±0.09?。

A soft X-ray polarimeter with multilayer was developed at the Beijing Synchrotron Radiation Facility （BSRF）. The polarimeter was designed to utilize reflection and transmission geometry, and it has four operational modes. Some experiments have been performed by using this polarimeter with various modes. Polarization properties of Mo/Si and Cr/C multilayer were measured, and polarizing characteristics of the Beamline 3W1B were measured systemically at BSRF. The degree of linear polarization is up to 0.995 from 0.585 at 206 eV when the beam is polarized by multilayer optical elements. We also measured magneto-optical Faraday rotation around the M2.3 edges （60-70 eV） of Ni film. The results demonstrate that the Faraday rotation angles are obviously large around Ni M2.3 edges, the rotation angles are 1.85±0.19° and -0.75±0.09°at the energy 65.5 eV and 68 eV, respectively.