ABOUT SECONDARY EXTINCTION IN TEXTURELESS POLYCRYSTALS

A brief calculation is made to estimate the amount of secondary extinc tion in polycrystals with no preferred orientations. To this end, use has been made of the Zachariasen's general theory of X-ray diffraction in crystals, together with corrections introduced by Cooper and Rouse . It was found, that secondary extinction is negligible, so that any e xtinction observed is primary in origin, which is related to the dislo cation density.