Well said but a few details are a bit off. The alternating plates of metal and detector is actually the hadronic calorimeter, which the muons also go straight t

Well said but a few details are a bit off. The alternating plates of metal and detector is actually the hadronic calorimeter, which the muons also go straight through (but which stop almost everything else). The muon detectors are outside of that, and are just various types of spark chambers that get zapped as the muon passes through them. Generally the muons neither stop nor decay in the detector.