Implications of gnomonic distortion on electron backscatter diffraction and transmission Kikuchi diffraction. (4th January 2022)

• Record Type: Journal Article
• Authors: Fancher, Chris M.; Burch, Matthew J.; Patala, Srikanth; Dickey, Elizabeth C.
• Is Part Of: Journal of microscopy. Volume 285:Part 2(2022)
• Page Start: 85
• Page End: 94
• Publication Date: 2022-01-04
• Subjects: EBSD -- gnomonic distortions -- TKD; Microscopy -- Periodicals; 502.82
• DOI: 10.1111/jmi.13077
• Languages: English
• ISSNs: 0022-2720

Abstract

Abstract: The effect of gnomonic distortion on orientation indexing of electron backscatter diffraction patterns is explored through simulation of electron diffraction patterns for sample‐to‐detector geometries associated with transmission Kikuchi diffraction (TKD) and electron backscatter diffraction (EBSD). Simulated data were analysed by computing a similarity index for both Hough transformed data and simulated patterns to determine the sensitivity of each method for detecting subtle differences in the effect of gnomonic distortions on electron diffraction patterns. These results indicate that the increased gnomonic distortions in electron diffraction patterns for a TKD geometry enhance the sensitivity for detecting subtle differences in interband angles. Additionally, the utilisation of a Hough transform‐based indexing approach further enhances the sensitivity. Non‐technical abstract: Electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD) have become vital tools for studying materials. These probes provide information about how locally arranged. EBSD and TKD utilise different experimental configurations that have impacts the measured data. The projection of the electron diffraction Ewald's sphere onto the face of the detectors results in Gnomonic distortions, and the selection of experimental configuration affects the magnitude of these distortions. In this work we used simulated dynamical electron diffraction patterns (EDPs) to understand the how differences in the EBSD and TKD experimental configurations impacts Gnomonic distortions and how these distortions effect the sensitivity of each method for detecting subtle differences in interband angles. These results indicate that the increased gnomonic distortions in electron diffraction patterns for a TKD geometry enhance the sensitivity for detecting subtle differences in interband angles. These results also suggest that a traditional Hough transform approach for indexing EDP data is less sensitive to detecting slight deviations than direct analysis of EDPs.