RAPID: an ImageJ macro for indexing electron diffraction zone axis spot patterns of cubic materials

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Accurate crystallographic analysis is crucial for materials characterization.
• Indexing electron diffraction patterns is a fundamental technique in transmission electron microscopy (TEM).
• Previous methods for indexing diffraction patterns can be time-consuming and require specific calibration.

Purpose of the Study:

• To introduce RAPID (ratio-method pattern indexing), an ImageJ macro script for automated electron diffraction pattern indexing.
• To provide a tool for rapid assessment of cubic crystal systems and Bravais lattices.
• To enable determination of lattice parameters and verification of camera constants.

Main Methods:

• Development of an ImageJ macro script named RAPID.
• Utilizes the R ratio principle for indexing calibrated and uncalibrated zone axis aligned electron diffraction patterns.
• Applies to selected-area electron diffraction patterns, nanobeam electron diffraction patterns, TEM Kikuchi patterns, and FFTs of HR(S)TEM images.

Main Results:

• RAPID allows instant indexing of electron diffraction patterns from cubic lattices.
• The software can distinguish between P, I, and F Bravais lattices for specific zone axis orientations.
• Accurate lattice parameters can be obtained from calibrated patterns, facilitating material verification and phase identification.
• Camera constant determination and verification are also supported.

Conclusions:

• RAPID is a convenient and efficient tool for on-site crystallographic analysis in TEM laboratories.
• The software aids in quickly determining if a material belongs to the cubic crystal system.
• RAPID enhances the capabilities for materials identification and structural analysis using electron diffraction data.