The gas monitoring system for the Resistive Plate Chamber detector of the CMS experiment at LHC

Due to its large volume (18 m3)the Resistive Plate Chamber (RPC) detector of the Compact Muon Solenoid (CMS) experiment at the LHC proton collider (CERN, Switzerland) will employ a gas re-circulation system. Since the mixture composition and quality are crucial issues for the detector operation, CMS-RPC will use an online gas analysis and monitoring system. An overview of both the CMS-RPC gas system and gas monitoring system is given and the project parameters are described.