Indexing of planar defects from the relative change of the apparent width by computer

A method is discussed, which provides quick and unique indexing of a planar defect only from the relative change of its apparent width when the crystal is tilted in the goniometer stage of a transmission electron microscope. Two micrographs are necessary, showing different apparent widths of the defect and three diffraction patterns of arbitrary negative beam direction B, to index the foil normal and the goniometer axis II. Neither a calibration of the magnification nor the determination of the foil thickness is necessary, since the apparent widths may be supplied to the computer in arbitrary units. In addition to being of less experimental effort, this method also has accuracy that proves to be equal or better than that of other methods.