Quality control of straw tube detectors for the PANDA Forward Tracker

The Forward Tracker in the PANDA experiment at FAIR is based on straw detector modules, each containing a double layer of straws glued together and mechanically stabilized by the overpressure of the working gas mixture. In this paper, we present the procedures and test stands developed for quality control of produced modules. In addition to verifying basic properties of the straw detectors, including gas tightness, mechanical tension of the anode wire, and pulse amplitude, the positioning of the straws and anode wires in the module are also measured using a collimated X-ray beam from a 55 Fe source. Furthermore, module planarity is assessed using a laser distance sensor. The testing process is fully automated. Alongside the methodology and technical details of the test stands, we present the results obtained from tests of the first 50 modules produced.