Muon energies in extensive air showers

A magnetic spectrograph triggered by an extensive air shower array, was used to measure the momentum spectrum of muons in extensive air showers in the momentum range 1 - 40 GeV/c with zenith angles between 0 - 30deg, at an atmospheric depth of 880 g cm-2 and a mean distance from the shower core of 100 metres. The observed spectrum at this altitude virtually coincides with other measurements but disagrees with the theoretically calculated energy spectrum, using the model as in de Beer et al. (1966). A muon spectrum which satisfies the observations, is derived. (author)