  On the basis of the Extensive Air Shower data observed by the GAMMA
experiment the energy spectra and elemental composition of the primary cosmic
rays have been derived in the 1-100 PeV energy range. Reconstruction of the
primary energy spectra is carried out in the framework of the SIBYLL and QGSJET
interaction models and the hypothesis of the power-law steepening primary
energy spectra. All presented results are derived taking into account the
detector response, reconstruction uncertainties of EAS parameters and
fluctuation of EAS development.

Astrophysics