A DigitalMicrograph® script RAPID-DM (RAtio method Pattern InDexing) has been developed, which allows instant on-site indexing of zone axis electron diffraction patterns of cubic lattices using the Rn ratio principle. In addition to indexing spot electron diffraction patterns, the program is also capable of indexing Kikuchi patterns taken from or near a zone axis. Both cases are demonstrated by examples for silicon. The program has a guided workflow and requires only three user-defined lines or Kikuchi bands for indexing. RAPID-DM has been extensively tested and verified to work reliably with both calibrated and noncalibrated zone axis patterns and allows the user to easily evaluate whether the material under examination is cubic, pseudo-cubic, or neither. For calibrated patterns, the program provides an average value of the cubic lattice parameter, which can serve for phase identification in connection with a structural database or it can simply be used to verify the material under investigation. In its current state, the developed script has proved to be a valuable add-on to the DigitalMicrograph® platform in the authors' service laboratory, as it greatly simplifies on-site crystallographic analysis of electron diffraction patterns of steels, alloys, and ceramics, which frequently form cubic or pseudo-cubic structures.
Maroufidis et al. (2025) studied this question.