The RPC system of the OPERA experiment

The OPERA experiment is designed to study the νμ→ντνμ→ντ oscillation observing the ντντ appearance in a pure νμνμ beam over a base line of 732 km from CERN to Gran Sasso Laboratory. The apparatus consists of a lead/emulsion-film target complemented by electronic detectors and muon spectrometers for muon charge and momentum measurements. The tracking inside the magnets is provide by Bakelite RPC chambers in a large scale application. The commissioning of the RPC system ended in August 2006. The paper present the layout of the RPC system and its performances.