Implications of gnomonic distortion on electron backscatter diffraction and transmission Kikuchi diffraction.

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD) are crucial for materials characterization.
• Gnomonic distortion in diffraction patterns can affect orientation indexing accuracy.
• Understanding these distortions is key to improving analytical precision.

Purpose of the Study:

• To investigate the impact of gnomonic distortion on orientation indexing in EBSD and TKD.
• To evaluate the sensitivity of different analysis methods to these distortions.
• To determine how TKD geometry and Hough transform indexing influence distortion effects.

Main Methods:

• Simulated electron diffraction patterns for EBSD and TKD geometries.
• Analysis using a similarity index comparing Hough transformed data and simulated patterns.
• Assessment of sensitivity to subtle differences caused by gnomonic distortions.

Main Results:

• Increased gnomonic distortions in TKD geometry enhance sensitivity to interband angle variations.
• Hough transform-based indexing significantly boosts the sensitivity of orientation indexing.
• The study quantifies the influence of geometry on distortion effects.

Conclusions:

• TKD geometry, with its inherent gnomonic distortions, offers improved detection of subtle crystallographic variations.
• Combining TKD with Hough transform indexing provides a highly sensitive method for analyzing electron diffraction patterns.
• This approach enhances the precision of crystallographic orientation analysis.