The reciprocal lattice construction from axial coordinates of diffraction spots on Weissenberg photographs

Abstract

An alternative method for constructing of the reciprocal lattice planes from Weissenberg photograph is presented. The radial coordinates of the diffraction spots necessary for the reciprocal lattice plane construction in current method are not introduced into this procedure. The method takes advantage of the coupling of the rotational and translatory motion of the Weissenberg camera. Both the magnitudes and the mutual orientations of the reciprocal lattice vectors can be then determined solely from the measured axial coordinates of the diffraction spots on the Weissenberg photographs. The knowledge of the camera radius as well as the non-uniformity of the radial adhesion of the film to the camera are thus fairly eliminated. The method was successfully applied to the interpretation of Weissenberg photographs of small fragments of lunar olivines from the Sea of Fertility (Luna 16 sample).