A texture goniometer with variable radius and collimation for analysis of textures in rocks

A texture goniometer has been built specifically for geologic applications. Features include (1) a large and variable radius, (2) a variable collimation system that is simple to use and which permits excellent resolution, (3) a wide main circle that allows large specimens to be analysed, (4) partial vacuum paths for the incident and diffracted beams, (5) a θ:2θ drive that allows 2θ scans. The performance of the goniometer is assessed by determining resolution and count rate for various collimations and radii.