Personal View: Two Decades of Mature X-ray Optics at SR Facilities

Abstract

Paul Ewald presented his thesis work on February 16, 1912, to the Philosophical Faculty of the University of Munich. The Dynamical Theory of X-ray Diffraction in perfect crystals was borne, though it was not until June of that year that Laue, Friedrich and Knipping's discovery of X-ray diffraction by crystals was announced [1]. Though steady progress was made in X-ray analysis throughout the 20th century, perfect crystal optics developed slowly because there were almost no perfect crystal samples – just some natural quartz, calcite and diamonds. High quality synthetic rock salt was grown in the 1930s but reliable supplies of germanium and silicon only came much later. Now we have large, almost-perfect synthetic samples of them and of diamond.