Sur deux variantes de la méthode de Laue et leurs applications

A geometrical property of white X-radiation diverging from a point source and reflected in a given family of crystal planes makes it possible to obtain photographs from which the scatter of the normals to these planes may be determined with an accuracy of 10 seconds of arc, even in a relatively large crystal. In this way the degree of perfection of certain crystals has been assessed and a new type of imperfection has been discovered. An alternative experimental arrangement gives an image of the crystal from which its position and orientation and the position of a region of imperfection can be determined.