Use of a Geiger Counter for the Measurement of X-Ray Intensities from Small Single Crystals

Abstract

In a recent crystal structure study, new techniques for intensity measurements utilizing a Geiger counter have been developed and are described. The present application involves the adaptation of standard Geiger-counter circuitry and equipment to a standard Weissenberg x-ray goniometer, so that diffraction intensities given by small (0.1 mm) single crystals are measured by means of a Geiger tube mounted in place of the film holder. The principle of measurement consists of the use of parallel collimated radiation and a scanning of the characteristic x-ray peak in order to obtain the integrated intensity. The measurement is made by totalizing counts on an impulse register while rocking the crystal, and correcting for background by measuring the rate-meter chart record which is made simultaneously with counting. Details of procedure and range of the method are given. The application of the method to the study of the crystal structure of tetragonal barium titanate is described.