The Moving Beam Diffraction Geometry: the DIAD Application of a Diffraction Scanning-Probe
Diamond Light Source（钻石光源）；The University of Manchester（曼彻斯特大学）；National Synchrotron Light Source II, Brookhaven National Laboratory（美国国家同步辐射光源二号，布鲁海文国家实验室）；University of Basel（巴塞尔大学）
Alberto Leonardi, Andrew James, Christina Reinhard, Michael Drakopoulos, Ben Williams, Hans Dehyle, Jacob Filik, Liam Perera, Sharif Ahmed
备注：
Accepted for publication in Journal of Applied Crystallography
理解微观结构、应变、相态与材料行为之间的相互作用在许多科学领域中至关重要。然而，量化这些相关性具有挑战性，因为这需要使用多种仪器和技术，而这些仪器和技术往往在空间和时间上相互分离。Diamond 光源的双成像与衍射（DIAD）光束线正是为应对这一挑战而设计的。DIAD 使用户能够可视化内部结构、识别成分/相变并测量应变。DIAD 提供两束独立光束并在同一样品位置汇合，从而能够准同时进行 X 射线计算机断层扫描和 X 射线粉末衍射。DIAD 配置的一项独特功能是能够执行图像引导衍射，即在不移动样品的情况下，让微米级衍射光束扫描成像视场的整个区域。这种移动光束衍射几何结构使得研究快速演化和易受运动影响的过程与样品成为可能。本文讨论了新颖的移动光束衍射几何结构，并介绍了关于所用几何校准与数据还原流程可靠性的最新发现。我们的测量证实，对于位于入射光束下游法线方向的探测器位置，衍射对移动几何结构最为敏感。观测数据证实，KB 镜与固定孔径狭缝耦合运动会导致光束探针发生刚性平移，而不会改变入射光束路径到达样品的角度。我们的测量表明，当校准样品区域与被探测样品区域之间的距离小于或等于光束光斑尺寸时，最近邻校准可以达到与自校准几何结构相同的精度。我们证明移动光束衍射几何结构的绝对误差保持在 0.0001 以下，这与我们在光束线稳定运行时所观测到的精度一致。
英文摘要：
Understanding the interactions between microstructure, strain, phase, and material behavior is crucial in many scientific fields. However, quantifying these correlations is challenging, as it requires the use of multiple instruments and techniques, often separated by space and time. The Dual Imaging And Diffraction (DIAD) beamline at Diamond is designed to address this challenge. DIAD allows its users to visualize internal structures, identify compositional/phase changes, and measure strain. DIAD provides two independent beams combined at one sample position, allowing quasi-simultaneous X-ray Computed Tomography and X-ray Powder Diffraction. A unique functionality of the DIAD configuration is the ability to perform image-guided diffraction, where the micron-sized diffraction beam is scanned over the complete area of the imaging field of view without moving the specimen. This moving beam diffraction geometry enables the study of fast-evolving and motion-susceptible processes and samples. Here, we discuss the novel moving beam diffraction geometry presenting the latest findings on the reliability of both geometry calibration and data reduction routines used. Our measures confirm diffraction is most sensitive to the moving geometry for the detector position downstream normal to the incident beam. The observed data confirm that the motion of the KB mirror coupled with a fixed aperture slit results in a rigid translation of the beam probe, without affecting the angle of the incident beam path to the sample. Our measures demonstrate a nearest-neighbour calibration can achieve the same accuracy as a self-calibrated geometry when the distance between calibrated and probed sample region is smaller or equal to the beam spot size. We show the absolute error of the moving beam diffraction geometry remains below 0.0001, which is the accuracy we observe for the beamline with stable beam operation.
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Investigation of the orientation relationship between nano-sized G-phase precipitates and austenite with scanning nano-beam electron diffraction using a pixelated detector
采用扫描纳米束电子衍射技术研究了奥氏体基体中纳米尺寸的辐照诱导G相（M $_6$ Ni $_{16}$ Si $_{7}$）析出物的取向关系。利用该探测器，可以同时分辨出由小G相颗粒产生的微弱衍射斑点和强烈的基体反射。使用两阶段模板匹配方案分析衍射图案，其中在减去对衍射图案的基质贡献之后，首先对基质进行索引，其次对沉淀物进行索引。结果表明，G相相对于奥氏体具有面心立方（FCC）向体心立方（BCC）转变的取向关系。这项工作表明，纳米束电子衍射与像素化检测器是一种很有前途的技术，以调查在其他材料系统中的纳米尺寸的沉淀物与复杂的晶体结构的取向关系相对容易。
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State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Future Material Innovation Center, Zhangjiang Institute for Advanced Study, Shanghai Jiao Tong University（上海交通大学）；School of Physics and Electronics, Hunan Key Laboratory of Super Microstructure and Ultrafast Process, State Key Laboratory of Powder Metallurgy, Central South University（中南大学）；Research Center for Scientific Data Hub, Zhejiang Lab（浙江实验室）；School of Physics and Astronomy, Shanghai Jiao Tong University, Key Laboratory for Particle Astrophysics and Cosmology (MOE), SKLPPC（上海交通大学）；School of Mechanical Engineering, Shanghai Jiao Tong University（上海交通大学）
The Exit-Wave Power-Cepstrum Transform for Scanning Nanobeam Electron Diffraction: Robust Strain Mapping at Subnanometer Resolution and Subpicometer Precision
Emerging hierarchical dislocation structures: Insights from scanning electron microscopy-electron backscatter diffraction in situ tensile testing and multifractal analysis
Characterization of WSe$_2$ films using reflection Kikuchi diffraction in the scanning electron microscope and multivariate statistical analyses
University of British Columbia（不列颠哥伦比亚大学）；Thermo Fisher Scientific（赛默飞世尔科技）；Central European Institute of Technology, Brno University of Technology（布鲁诺理工大学中欧研究所）；Institute of Physical Engineering, Brno University of Technology（布鲁诺理工大学物理工程学院）；Thermo Fisher Scientific, Materials Science（赛默飞世尔科技材料科学部）
A method for crystallographic mapping of an alpha-beta titanium alloy with nanometre resolution using scanning precession electron diffraction and open-source software libraries
Mapping Order in Semicrystalline Polymers using Machine Learning of Nanobeam Electron Diffraction
Department of Materials Science and Engineering, Stanford University（材料科学与工程系，斯坦福大学）；SLAC National Accelerator Laboratory（SLAC国家加速器实验室）；National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory（电子显微镜国家中心、分子发现所、伯克利国家实验室）
Fast Grain Mapping with Sub-Nanometer Resolution Using 4D-STEM with Grain Classification by Principal Component Analysis and Non-Negative Matrix Factorization
