A Diffractometer Control System with Automatic UB-matrix Refinement

A four-axes diffractometer control system with automatic UB-matrix refinement has been developed. The system automatically scans and finds peak positions after specifying a set of indexes, then the system calculates the UB-martix. Combining with continuous scan, the control system reduces a UB-matrix determination time. The system was developed based on a message exchanging control framework. Users can control not only a diffractometer but also other components like a monochromator and an insertion device using man-readable abstract messages. Therefore users easily develop programs for their experiments. Results of test measurements at the beamline BL46XU of the SPring-8 indicate that the automatic UB-matrix refinement is working well, and it reduces the refinement time of the UB-matrix about one fourth.