Contents

ABSTRACT: ALICE (A Large Ion Collider Experiment) studies the transition of nuclear matter to a deconfined phase known as Quark Gluon Plasma, in ultra-relativistic heavy-ion collisions at the LHC. ALICE is equipped with a muon spectrometer for the detection of quarkonia and heavy flavour particles. The trigger system of the spectrometer consists of 72 RPCs arranged in four detection planes, with a total area of 140 m2. In the first three years of LHC operation, the muon trigger system was fully operational in data-taking in pp, Pb-Pb and p-Pb collisions. The RPC performance and stability throughout the whole data-taking period is presented and discussed, for the parameters such as the efficiency, the dark counting rate, the dark current and the cluster size