Introduction. Electron diffraction is sometimes considered to be a “difficult subject”. It is certainly one that can not be covered in the space available here. Rather this tutorial will present a few specific aspects of the topic. The topics have been chosen in the hope that they will provide illumination that spreads more widely than just onto the material presented. Several books treat electron diffraction with more generality.

Kikuchi lines Kikuchi lines are of great use in orienting a sample. Unfortunately, in modern microscopes, Kikuchi lines are not seen in selected-area diffraction (SAD). This is because immersion lenses send parallel electrons, from different parts of the sample (like the Kikuchi lines from a flat specimen), to different places in the diffraction pattern. Thus Kikuchi lines are blurred and generally not useful whenever, as in SAD patterns, a large area of the sample contributes to the diffraction pattern.