Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at √s = 13 TeV

The Level-1 muon trigger system of the ATLAS experiment at the Large Hadron Collider (LHC) selects muon candidates with six transverse momentum thresholds and associate them with the correct LHC bunch crossing. Resistive Plate Chambers (RPC) detectors are used in the barrel region of the Muon Spectrometer to generate trigger signals within the pseudorapidity range up to 1.05. The RPC detectors are arranged in three concentric double layers and consist of 3600 gas volumes, with a total surface of more than 4000 square meters. They operate in a toroidal magnetic field of approximately 0.5 Tesla and provide up to 6 position measurements along the muon trajectory, with a space-time resolution of about 1 cm x 1 ns. This contribution will discuss the performance of the RPC detector and Level-1 Muon Barrel trigger system during the latest data taking period at a centre-of-mass energy of 13 TeV. Measurements of RPC detector response obtained using muon candidates produced in LHC collisions will be presented. Trigger performance and efficiency measurements, obtained using Z boson decays to a muon pair, will be also summarized. Finally, studies of the RPC detector response at different voltage and threshold settings, as well as the gas-gap current measurements as a function of the instantaneous luminosity, will be discussed, also in the context of the expected detector performance after the High Luminosity LHC upgrades.