Muon Content of Extensive Air Showers: Comparison of the Energy Spectra Obtained by the Sydney University Giant Air-Shower Recorder and by the Pierre Auger Observatory

The Sydney University Giant Air-shower Recorder(SUGAR) measured the energy spectrum of ultra-high-energy cosmic rays reconstructed from muon detector reading. Comparison of their spectra SUGAR and Pierre Auger Observatory allows us to reconstruct the empirical dependence of the number of muons in a vertical shower on the primary energy for energies between 10¹⁷ and 10¹⁸ eV. We compared this dependence with the predictions of hadronic interaction models QGSJET-II-04, EPOS-LHC and SIBYLL-2.3c. In addition, we analyzed the response of the array of muon detectors in order to determine the slope of the muon lateral distribution function. It is important to understand how much the number of muons differs from the predictions of modeling at different distances from the shower axis.