Practical accuracy of grain misorientation measurements by Kikuchi line technique

A practical procedure for crystal orientation determination from electron diffraction patterns using the computerized method of Heilmann et al. is described which is believed to give the most accurate results. It is shown that more than three reflections are generally needed. The accuracy of the orientation measurement may be increased if in addition to the direction of the Kikuchi lines the directions of the lines connecting the diffraction spots with the pattern centre are measured as well. It is expected that the grain misorientations can be established to accuracy of +/- 0.1 degrees in magnitude of angle and +/- 0.2 degrees in the direction of the rotation axis.