Testing of large size GEM detector with Pb+Pb collision at CERN-SPS

Large size triple GEM (Gas Electron Multiplier) detectors will be used for the first two stations of MUCH (Muon Chamber) in CBM (Compressed Baryonic Matter) experiment which face high particle rate and harsh radiation environment. We tested two large size prototype detectors with particles coming from the Pb+Pb collisions at different beam momenta (13 AGeV/c, 30AGeV/c and 150 AGeV/c). Simultaneous response from the full active area of the detector was studied unlike with single particle beam. The performance of the detector in a multiparticle environment was studied for the first time wherein spray of particles produced from nucleus-nucleus collision passed through different regions of the detector, as the case would be in the actual CBM experiment. Data with 20 cm Fe absorber were also taken. This test was carried out at the H4 beam-line of CERN-SPS. This was also the first test with new CBM-DAQ, which took data in a free streaming mode