0.5 mm金刚石X射线相位延迟板及偏振度的标定

在利用步辐射光源的偏振特性进行自旋相关X射线散射及吸收谱实验来研究材料的磁学性质时，需要应用圆偏振光，这就提出了对具有高通量、高偏振度' 长连续可调的圆偏振X射线的需求；另一方面标定实验所用X射线的圆偏振度也成为这一研究领域的关键技术。由于X射线多光束衍射强度与σ场和π场的光程差δ相关，通过测量圆偏振分析晶体的多光束衍射的强度分布，可以获得入射X射线的圆偏振度。实验在美国国家同步辐射光源实验室X25光束线实验站进行，光子能量为7．1keV的圆偏振X射线由线偏振X射线经过一厚度为0．5mm、晶面为111]的金刚石晶体产生。通过测量多光束衍射强度，确定了斯托克斯参量。实验值与X射线动力学理论计算结果能较好地吻合。

0.5 mm Diamond Crystal for X-Ray Phase Retarder and Determination Its Polarimetry

When using the synchrotron radiation to do spin dependent scattering and absorption experiments, it gives rise to the demands for a high flux, tunable wavelength, and high degree circular polarized X ray source. Thus the technical methods to determine the polarimetry for circular polarized X ray are highly demanded. The 7.1 keV circular polarized X ray was produced from X25 beamline of NSLS, by passing a 0.5 mm thickness diamond crystal with the crystal surface along direction for diffraction serving as X ray phase retarder. The Stokes parameters were determined by measuring the multiple beam diffraction intensity. A comparison between the measured results and the X ray dynamical theory is given, which shows perfect agreement between them