Kikuchi pattern simulations of backscattered and transmitted electrons.

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD) are crucial for materials characterization.
• Accurate simulation of Kikuchi diffraction patterns is essential for quantitative analysis.
• Existing models may not fully capture complex diffraction phenomena like excess-deficiency features.

Purpose of the Study:

• To introduce a refined simulation approach for Kikuchi diffraction patterns in EBSD and TKD.
• To investigate the impact of excess-deficiency features on pattern analysis.
• To develop a model for improving the accuracy of pattern matching applications.

Main Methods:

• Developed a simulation model combining dynamical diffraction from point sources and incoherent diffuse intensity.
• Incorporated a phenomenological model for excess-deficiency features based on the two-beam approximation.
• Applied the model to analyze the effect of incident beam geometry and crystal defects.

Main Results:

• The refined model successfully reproduces thickness- and energy-dependent features in experimental Kikuchi patterns.
• Excess-deficiency features are accurately modeled by considering gradients in incoherent background intensity.
• Neglecting excess-deficiency effects can lead to significant biases in fitted projection center coordinates and strain determination in EBSD/TKD.

Conclusions:

• The refined simulation approach provides a more accurate representation of Kikuchi diffraction patterns.
• Accounting for excess-deficiency features is critical for reliable quantitative analysis in EBSD and TKD.
• The developed model enhances the accuracy of pattern matching and simulation-based measurements.