Aging studies for the CMS RPC system

Aging effects are studied for the Resistive Plate Chambers (RPC) at the Compact Muon Solenoid (CMS) experiment at the CERN Large Hadron Colider (LHC), which can manifest themselves during the High-Luminosity LHC (HL-LHC) running period. A dedicated consolidation program is set up using the CERN Gamma Irradiation Facility ++, where RPC detectors are exposed to a high gamma flux for a long term period equivalent to the HL-LHC operational time. Based on the past operational experience, the high background conditions are estimated and the RPC are tested under such circumstances. Several parameters are monitored as function of integrated charge and dedicated test beam periods allows measuring the detector efficiency as function of the background rate. In this work, an overview of the measurements which were performed for these studies is given. After having accumulated a significant amount of the total irradiation, no aging effects or degradation of the RPC detectors have been observed. These results suggest that the RPC system is capable to handle the HL-LHC conditions.