Small-angle X-ray scattering (SAXS) is a technique for obtaining low-resolution structural information about biological macromolecules, by exposing a dilute solution to a high-intensity X-ray beam and capturing the resulting scattering pattern on a two-dimensional detector. The two-dimensional pattern is reduced to a one-dimensional curve through radial averaging; that is, by averaging across annuli on the detector plane. Subsequent analysis of structure relies on these one-dimensional data. This paper reviews the technique of SAXS and investigates autocorrelation structure in the detector plane and in the radial averages. Across a range of experimental conditions and molecular types, spatial autocorrelation in the detector plane is present and is well-described by a stationary kernel convolution model. The corresponding autocorrelation structure for the radial averages is non-stationary. Implications of the autocorrelation structure for inference about macromolecular structure are discussed.

中文翻译：

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小角 X 射线散射实验中径向平均值的自协方差结构


小角 X 射线散射 (SAXS) 是一种通过将稀溶液暴露于高强度 X 射线束并在二维探测器上捕获所得散射图案来获取有关生物大分子的低分辨率结构信息的技术。通过径向平均将二维图案简化为一维曲线；也就是说，通过对检测器平面上的环进行平均。后续的结构分析依赖于这些一维数据。本文回顾了 SAXS 技术并研究了探测器平面和径向平均值中的自相关结构。在一系列实验条件和分子类型中，检测器平面中存在空间自相关性，并且可以通过固定核卷积模型很好地描述。径向平均值的相应自相关结构是非平稳的。讨论了自相关结构对于大分子结构推断的影响。