The Intensity of Reflection of X-Rays from Diamond

Abstract

Ionization spectrometer measurements of the intensity of reflection of the $K\alpha$ doublet of molybdenum by fine diamond powder were made by the transmission method. The diameter o the individual particles was ${10}^{-4\mathrm{}}$ cm or less, whereas 3×${10}^{-5\mathrm{}}$ cm is the length of the cube edge of a block small enough so that primary extinction, calculated from Darwin's formula, be less than 1 percent. Secondary extinction was probably negligible. The relative intensities of the radiation reflected from the different planes of the diamond were obtained by comparisons of the areas under the peaks. From these relative intensities the relative $F$ values were obtained by use of a formula derived by Compton and modified to fit the conditions of this experiment. These relative values were placed on an absolute scale by comparison of the intensity of the (220) reflection of diamond with that of the (220) reflection of NaCl, for which the absolute value has been determined. The (222) reflection, previously observed by W. H. Bragg and by Ehrenberg, Ewald, and Mark in studies of single crystals, was also observed here. It might occur if the carbon atoms are of two kinds with different scattering powers, or if adjacent carbon atoms shared electrons between them in such a way as to provide scattering centers upon the line joining them. Neither explanation, however, is entirely compatible with the experimental data. A Fourier analysis was applied to the data and the resulting distribution curves compared with those calculated by Havighurst from Hull's and Bragg's data.