A Modified Diffractometer for X-ray Stress Measurements

Usually, the classical Bragg-Brentano diffractometer arrangement is used for X-ray strain measurements. For measurements in different ψ-directions, the specimen is rotated clockwise or counter-clockwise around the diffractometer axis using a separate driving system (ω-diffractometer).During the measurements, primary and reflected X-ray beams are placed in the same plane as the normal of the specimen and the normals of the measured ﹛h,k,l﹜ -planes. However, the Bragg- Brentano principle also can he applied to strain measurements in different ψ-directions with a number of advantages if the specimen is rotated around an axis lying parallel to the diffractometer plane (ψ- diffractometer) (1). The principle, construction and characteristics of the ψ-diffractometer are described and compared with those of the ω-diffractometer.