Environment-friendly gas mixtures for Resistive Plate Chambers: an experimental and simulation study

International audienceResistive Plate Chambers (RPC) have shown stable operation at the Large Hadron Collider and satisfactory efficiency for the entire Run 1 (2010–2013) and Run 2 (2015–2018) with C2H2F4-based gas mixtures and the addition of SF6 and i-C4H10. Since its global warming potential (GWP) is high, C2H2F4 is phasing out of production due to recent European Union regulations and as a result its cost is progressively increasing. Therefore, finding a new RPC gas mixture with a low GWP has become extremely important. This contribution describes the simulation of the RPC efficiency with tetrafluoropropene C3H2F4 (HFO1234ze), a hydrofluoroolefin with very low GWP. Simulation results are systematically compared with measurements of RPC efficiency in C3H2F4-based gas mixtures with the addition of different combinations of Ar, He, CO2, O2 and i-C4H10 in various concentrations. This simulation allows the study of the interplay between C3H2F4 and the other gas components in the mixture as well as may allow the identification of the most promising environment-friendly gas mixtures with C3H2F4 for RPCs