Primary-cosmic-ray energy spectrum up to 50 TeV derived from sea-level muon measurements

The energy spectrum of the primary cosmic radiation has been derived from measurements of the muon energy spectrum at sea level with the DEIS spectrometer. The measured data have been fitted with production models using least-squares fit techniques. The obtained primary spectrum is in agreement with results from direct measurements at lower energies. In the energy range 150 TeV the power index has the value =2.72+0.02.