The angular precision of crystal orientation determination by cross-correlating dynamically simulated electron diffraction patterns with experimental patterns via spherical harmonic analysis is investigated. The best precision found in this study is 0.016°, which approaches the level reported in the literature for other high-precision electron backscatter diffraction implementations. At this angular precision, the noise floor for geometrically necessary dislocation density calculations is found to be approximately 5×1013 m-2 at a 200 nm step size. Conventional Hough-transform indexing of the same raw patterns gave an angular precision of 0.156° and a dislocation noise floor of 6×1014 m-2, an order of magnitude larger for both parameters, albeit better than is typical for Hough indexing due to the high-quality patterns used. Experimental trade-off curves of precision versus exposure time, pattern resolution (i.e. camera binning), and analysis bandwidth are also presented, allowing for optimization of data collection and analysis rates once the desired level of precision has been determined.

中文翻译：

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电子背散射衍射图的球谐变换索引的高精度方向映射

研究了通过球谐分析将动态模拟电子衍射图案与实验图案相互关联来确定晶体取向的角度精度。本研究中发现的最佳精度为 0.016°，接近文献中报告的其他高精度电子背散射衍射实现的水平。在此角度精度下，几何上必要的位错密度计算的本底噪声约为 5×1013 m-2，步长为 200 nm。相同原始模式的传统霍夫变换索引给出了 0.156° 的角度精度和 6×1014 m-2 的位错噪声本底，这两个参数都大一个数量级，尽管比霍夫索引的典型值要好，因为使用了高质量的图案。