Intensity measurements of low energy cosmic ray muons underground

Intensities of cosmic ray muons coming to rest in a 4441 liquid scintillator tank at depths 96, 417 and 985 hg cm-2 (1 hg cm-2=100 g cm-2 of matter underground) have been measured. It is concluded that the observations can be accounted for in terms of muons produced in the atmosphere and penetrating to the respective depths, and muons generated locally by the decays of pions which are in turn produced in the hadronic cascades initiated by high energy muons via photomeson production by the virtual and real photons associated with muons. No new process for low energy muon production is required at the depths investigated.