Department of Physics, Yale University, New Haven, CT 06511, USA.
J Synchrotron Radiat. 2011 Nov;18(Pt 6):823-34. doi: 10.1107/S0909049511037149. Epub 2011 Oct 5.
The newly introduced coherence-based technique of X-ray near-field speckle (XNFS) has been implemented at 8-ID-I at the Advanced Photon Source. In the near-field regime of high-brilliance synchrotron X-rays scattered from a sample of interest, it turns out that, when the scattered radiation and the main beam both impinge upon an X-ray area detector, the measured intensity shows low-contrast speckles, resulting from interference between the incident and scattered beams. A micrometer-resolution XNFS detector with a high numerical aperture microscope objective has been built and its capability for studying static structures and dynamics at longer length scales than traditional far-field X-ray scattering techniques is demonstrated. Specifically, the dynamics of dilute silica and polystyrene colloidal samples are characterized. This study reveals certain limitations of the XNFS technique, especially in the characterization of static structures, which is discussed.
新引入的基于相干性的 X 射线近场散斑（XNFS）技术已在高级光源的 8-ID-I 上实现。在高亮度同步加速器 X 射线从感兴趣的样品散射的近场区域中，当散射辐射和主光束都照射到 X 射线面探测器上时，测量的强度显示出低对比度的散斑，这是由于入射光束和散射光束之间的干涉。已经构建了具有高数值孔径显微镜物镜的微米分辨率 XNFS 探测器，并证明了其在比传统远场 X 射线散射技术更长的长度尺度上研究静态结构和动力学的能力。具体而言，稀二氧化硅和聚苯乙烯胶体样品的动力学特征得到了表征。这项研究揭示了 XNFS 技术的某些局限性，特别是在静态结构的表征方面，对此进行了讨论。
