Lattice constant determination from Kossel patterns observed by CCD camera

The Kossel technique is known due to its precision for lattice constant det ermination in micro ranges by use of X-ray films. Recently we observed the Kossel interferences also by a CCD camera in a good quality. Thus, the diff raction interferences could be immediately processed and evaluated by compu ter permitting considerable time saving. In order to obtain the similar acc uracy as for measurements with X-ray films further technical and experiment al improvements were necessary, especially for a better contrast to observe intersection points of several weak reflections, for evaluating digital pa tterns, for optimizing of the shortest focus-screen distance and for consid ering the image field curvature of the objective. As a result, a precision in lattice constant determination could be achieved at a Fe-crystal coming relatively close to the one of comparable X-ray film patterns, which is sti ll about one order of magnitude better for the time being. (C) 2001 Elsevie r Science B.V. All rights reserved.