Performance of the ATLAS RPC detector and Level-1 muon barrel trigger at $\sqrt{s}$ = 13 TeV

The ATLAS experiment at the Large Hadron Collider utilises a trigger system consisting of a first level (Level-1) trigger based on custom hardware and a higher level trigger based on computer farms. The Level-1 muon trigger system selects muon candidates with six thresholds of transverse momenta and associate them with correct LHC bunch crossings. The Level-1 Muon Barrel Trigger uses Resistive Plate Chambers (RPC) detectors to form trigger decisions by identifying muon candidates with $|\eta | <$ 1.05. The RPC detectors are arranged in three concentric double layers and consist of 3700 gas volumes, with a total surface of more than 4000 square meters, that is operated in a toroidal magnetic field. The performance of the RPC detector system and of the Level-1 Muon Barrel trigger during the 2018 data taking period is discussed in this contribution. 60.8 fb$^{-1}$ out of total 62.2 fb$^{-1}$ data recorded by the ATLAS detector at LHC is used. Measurements of the RPC detector response and time resolution, obtained using muon candidates produced in LHC collisions are presented. Trigger performance and efficiency are measured with muons originating from the decay of the $Z$ bosons. Finally, studies of the RPC detector response at different high voltage (HV) and threshold settings are shown, as a preview of the expected detector performances after the High Luminosity LHC upgrades.