Speaker
Description
Resistive Plate Chamber (RPC) detectors in the Compact Muon Solenoid (CMS) experiment operate with a gas mixture comprised of 95.2% of C2H2F4, that provides a high number of ion-electron pairs, 4.5% of iC4H10, that ensures the suppression of photon-feedback effects and 0.3% of SF6, used as an electron quencher to further operate the detector in streamer-free mode. C2H2F4 is known to be a Greenhouse gas with a very high global warming potential (GWP) of 1430. Several alternatives to C2H2F4 have been studied in the last few years. In this context, one short-mid term approach could be to focus on adding CO2 in place of C2H2F4. The studies are done at CERN Gamma Irradiation Facility (GIF++) in the North Area of SPS, where a 13.6 TBq radiation source and a muon beam from SPS are used to mimic the conditions of Phase-II of LHC. This work will present the performance and aging of a 1.4 mm gap RPC chamber with three different CO2-based mixtures under a high gamma background, as well as the results after a second round of longevity period, integrating 80 mC/cm^2 of charge, almost 30% of the 300 mC/cm^2 expected for the High Luminosity LHC (HL-LHC) period.