Muon sea-level intensity and primary cosmic-ray nucleon spectrum in the (1÷100) TeV energy range from the Mt. Blanc underground experiment

Abstract

We have measured the muon intensity underground up to 7100 hg/cm2 s.r. by means of a spark chamber apparatus. These intensities have been converted to a sea-level muon energy spectrum. An accurate description of the flux of hadrons and muons in the atmosphere allows us to derive the primary nucleon spectrum. If the validity of the superposition model and scaling in the fragmentation region is assumed, we find that the all nucleon spectrum is represented by a single exponent over the whole energy range (1°100) TeV and is given by the relationN(E)dE=(4.85±0.25)E −(2.79±0.04)dE.