Testing Real-Size Triple GEM Chambers with Pb+Pb Collision at CERN SPS

We discuss the fabrication, assembly and beam tests of two large-size triple Gas Electron Multiplier (GEM) detector prototypes, of CBM Muon Chamber (MuCh), with Pb+Pb collisions at CERN SPS. This was the first prototype test in a multiparticle environment, wherein realistic CBM DAQ collected data from a large number of channels in a free streaming mode, using several nXYTER-based [1] Front End Boards (FEBs) and recording simultaneous hits from over a wide area of the GEM prototypes. The response of the detector and issues related to DAQ, electronics, cooling, etc. have been reported.