Nolze Gert, Tokarski Tomasz, Rychłowski Łukasz
Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin, Germany.
Institut für Mineralogie, TU Bergakademie Freiberg, Brennhausgasse 14, 09596 Freiberg, Germany.
J Appl Crystallogr. 2023 Feb 24;56(Pt 2):349-360. doi: 10.1107/S1600576723000134. eCollection 2023 Apr 1.
The derivation of a crystal structure and its phase-specific parameters from a single wide-angle backscattered Kikuchi diffraction pattern requires reliable extraction of the Bragg angles. By means of the first derivative of the lattice profile, an attempt is made to determine fully automatically and reproducibly the band widths in simulated Kikuchi patterns. Even under such ideal conditions (projection centre, wavelength and lattice plane traces are perfectly known), this leads to a lattice parameter distribution whose mean shows a linear offset that correlates with the mean atomic number of the pattern-forming phase. The consideration of as many Kikuchi bands as possible reduces the errors that typically occur if only a single band is analysed. On the other hand, the width of the resulting distribution is such that higher image resolution of diffraction patterns, employing longer wavelengths to produce wider bands or the use of higher interference orders is less advantageous than commonly assumed.
从单个广角背散射菊池衍射图案推导晶体结构及其特定相参数需要可靠地提取布拉格角。借助晶格轮廓的一阶导数，尝试在模拟菊池图案中完全自动且可重复地确定带宽。即使在这样的理想条件下（投影中心、波长和晶格平面迹线完全已知），这也会导致晶格参数分布，其平均值显示出与形成图案相的平均原子序数相关的线性偏移。考虑尽可能多的菊池带可减少仅分析单个带时通常出现的误差。另一方面，所得分布的宽度使得采用更长波长以产生更宽带或使用更高干涉级别的更高衍射图案图像分辨率并不像通常认为的那样有利。
