Muons - tiny, electron-like particles - are present in the final stages of many B meson decays, and so muon detection is vitally important for the LHCb experiment.
Located at the far end of the detector, the muon system comprises five rectangular ‘stations’, gradually increasing in size and covering a combined area of 435 m² - about the same size as a basketball court.
Each station contains chambers filled with a combination of three gases: carbon dioxide, argon, and tetrafluoromethane. The passing muons react with this mixture, and wire electrodes detect the results.
In total, the muon system contains around 1,400 chambers and some 2.5 million wires - enough to stretch from Geneva to Madrid.