Laue-Photograph taken with a Long Slit

Abstract

ORDINARY metals are composed of aggregates of small crystals. These small crystals may be made to grow, by suitable processes, to very much larger ones, so that we can obtain a test piece of proper size composed entirely of a single crystal of a metal. Such test pieces of single crystals of metals do not, as a rule, possess plane faces, that is, the external forms of crystals, but X-rays afford us a means of determining the orientations of the axes of such crystals. A. Müller (Proc. Roy. Soc., London, 1924) photographed the Laue-spots at various orientations of the specimen, and from the position of the characteristic K-radiations of the anticathode on the photograph, he determined the orientations of the axes of the crystal. Next, T. Fujiwara (Mazda Kenkyu Jiho, Tokyo Electric Co., 1926) achieved the same purpose by finding the characteristic K-radiation in some of the ordinary Laue-spots; while H. Mark, M. Polanyi, and E. Schmid (Zeit. für Phys., 1923), and K. Weissenberg (Zeit. für Phys., 1924) applied the method of rotating the crystals. All these authors employed a narrow and nearly parallel beam of X-rays, so that only a small portion of the specimen could be tested at one time.