Optical scanning system for quality control of GEM-foils

An optical scanning system was commissioned and further developed in the Detector Laboratory of Helsinki Institute of Physics and University of Helsinki. It was designed to automatically scan, perform on-line analysis and to classify the overall quality of GEM-foils especially of the GEM-TPC detectors for Super-FRS at FAIR. The optical scanning system consists of precision positioning table, lighting, optics and operating system with analysis software. It has active scanning area of 95×95 cm2 and it can study this area with the minimum resolution of 128 lp/mm. Performance of the system and first results from the GEM-foil uniformity and quality analysis are presented.