ACOM-TEM (Automated Crystal Orientation Mapping) is a TEM technique that automatically determines the crystal orientation at each point by matching experimental diffraction patterns to simulated templates — producing orientation maps with nanometer spatial resolution.

How Does ACOM Work?

• Scan: Raster a nanoprobe across the sample, recording a diffraction pattern at each point.
• Templates: Pre-compute simulated diffraction patterns for all possible orientations of the expected phases.
• Match: Cross-correlate each experimental pattern with all templates to find the best match.
• Map: Plot the orientation (as inverse pole figure colors) at each point.

Why It Matters

• TEM Resolution: Orientation mapping with ~2-5 nm spatial resolution (vs. ~50 nm for EBSD).
• Thin Films: Works on TEM foils — critical for studying nanocrystalline and thin-film materials.
• Phase + Orientation: Simultaneously identifies both the crystal phase and its orientation.

ACOM-TEM is EBSD for the TEM — automated crystal orientation mapping at nanometer resolution using template matching of diffraction patterns.