|Muons are particles just like electrons, but 200 times heavier. They are the only detectable particles that can traverse all the calorimeter absorbers without being stopped. The muon spectrometer surrounds the calorimeter and measures muon paths to determine their momenta with high precision.|
It consists of thousands of charged particle sensors placed in the magnetic field produced by large superconducting toroidal coils. The sensors are similar to the straws described for the inner detector, but with larger tube diameters.