Beam performance of tracking detectors with industrially produced GEM foils

Three Gas-Electron-Multiplier (GEM) tracking detectors with an active area of 10cm×10cm and a two-dimensional, laser-etched orthogonal strip readout have been tested extensively in particle beams at the Meson Test Beam Facility at Fermilab. These detectors used GEM foils produced by Tech-Etch, Inc. They showed an efficiency in excess of 95% and spatial resolution better than 70μm. The influence of the angle of incidence of particles on efficiency and spatial resolution was studied in detail.