The ATLAS muon trigger chamber system

The muon trigger system in ATLAS is designed to cover a wide rapidity interval of the ATLAS muon spectrometer (η⩽2.4). The components are the Resistive Plate Chambers in the barrel region (η⩽1) and the Thin Gap Chambers in the end-cap region (1⩽η⩽2.4). The trigger chambers provide bunch crossing identification and measurement of the second coordinate in the non-bending plane. Particular emphasis is put in describing the global muon trigger chamber system, the first-level trigger algorithm, the trigger efficiency and the trigger acceptance.