Triple GEM performance in magnetic field

Performance of triple GEM prototypes in strong magnetic field has been evaluated by means of a muon beam at the H4 line of the SPS test area at CERN. Data have been reconstructed and analyzed offline with two reconstruction methods: the charge centroid and the micro-Time-Projection-Chamber exploiting the charge and the time measurement respectively. Depending on the combination of the particle incident angle and magnetic filed, there's always one of the two algorithms achieving a spatial resolution of 100–120 μm.