Appendix G: Muon Characteristics

Abstract

Muons are leptons that have a rest mass of 105.7 MeV and a mean lifetime of 2.2 · 10 À6 s. They have a relatively large rest mass relative to that of the electron (0.511 MeV), and to first order these particles do not participate in the strong interaction. Muons can penetrate long distances into matter and are less susceptible to radiative effects compared to electrons. Over a broad energy range, the dominant energy loss mechanism is that of ionization. This makes the shielding of muons and the knowledge of their range considerably important at high-energy accelerators and in other high-energy applications. Muon radiation becomes more important as the accelerator energy increases.