Small-angle X-ray scattering using coherent undulator radiation at the ESRF.
Small-angle X-ray scattering using coherent undulator radiation at the ESRF.
复制标题
使用 ESRF 处的相干波荡器辐射进行小角度 X 射线散射。
DOI：
10.1107/s0909049597015835
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发表时间：
1998
影响因子：
2.5
通讯作者：
M. Sutton
中科院分区：
文献类型：
--
作者：
D. Abernathy;G. Grübel;S. Brauer;I. Mcnulty;G. Stephenson;S. Mochrie;A. Sandy;Norbert Mulders;M. Sutton
本文报道了一种用于欧洲同步辐射装置三驾马车光束线小角散射研究的高相干流X射线束的简单产生方法。对于这种小角度的研究，可以减小光束的纵向相干长度，从而增加光束的能带通和强度，因为只有很小的光程长度差。通过使用反射镜和滤光片从波荡器谐波结构中去除多余的能量，可以产生高通量的>；10(9)光子S(-1)通过8.2keV的5微米直径的针孔，带通为1.3%。通过分析气凝胶样品的静态散斑图样，测量了这种光束的相干特性。基于对使用部分相干条件获得的散斑图案的强度分布的统计分析，将散斑大小和对比度与期望值进行比较。发现了空间自相关的预期宽度，但光束存在明显的非相干部分，这降低了测量的对比度。该方法可作为优化相干X射线衍射实验条件的一种工具。
A simple approach for producing a high-coherent-flux X-ray beam for small-angle-scattering studies used at the Troika beamline of the European Synchrotron Radiation Facility is reported. For such small-angle studies it is permissible to reduce the longitudinal coherence .length of the beam, thus increasing the energy bandpass and intensity of the beam, because there is only a small optical path-length difference. By using mirrors and filters to cut unwanted energies from the undulator harmonic structure, a high-flux beam of >10(9) photons s(-1) through a 5 micron-diameter pinhole at 8.2 keV with a bandpass of 1.3% can be produced. The coherent properties of this beam have been measured by analyzing a static speckle pattern from an aerogel sample imaged by a directly illuminated CCD camera. The speckle size and contrast are compared with the expected values based on a statistical analysis of the intensity distribution of speckle patterns obtained using partially coherent conditions. The expected widths of the spatial autocorrelation are found, but there is an apparent incoherent fraction of the beam which reduces the measured contrast. The method presented is to be used as a tool to optimize conditions for diffraction experiments using coherent X-rays.