Performance of semitransparent silicon strip sensors for high precision optical alignment monitoring systems

Novel semitransparent optical position sensors (“ALMY sensors”) have been developed for the alignment monitoring systems of modern large-area tracking detectors. The high transmittance of up to 90% allows to align more than 10 sensors along a collimated laser beam. A position resolution of 1 μm and an uncertainty in the deflection of the traversing laser beam of less than 3 μrad have been achieved for sensitive areas of several square centimeters. For the thin-film amorphous silicon sensors, the required laser intensity could be minimized such that the performance is not deteriorated by aging effects