Full Monte-Carlo description of the Moscow State University Extensive Air Shower experiment

The Moscow State University Extensive Air Shower (EAS-MSU) array studied high-energy cosmic rays with primary energies ~(1-500) PeV in the Northern hemisphere. The EAS-MSU data are being revisited following recently found indications to an excess of muonless showers, which may be interpreted as the first observation of cosmic gamma rays at ~100 PeV. In this paper, we present a complete Monte-Carlo model of the surface detector which results in a good agreement between data and simulations. The model allows us to study the performance of the detector and will be used to obtain physical results in further studies.