The Cosmic Ray Mass Composition in the Energy Range 1015–1018 eV measured with the Tunka Array: Results and Perspectives

The final analysis of the Extensive Air Shower (EAS) maximum (Xmax) depth distribution derived from the data of Tunka-25 atmospheric Cherenkov light array in the energy range 3⋅1015–3⋅1016 eV is presented. The perspectives of Xmax studies with the new Cherenkov light array Tunka-133 of 1 km2 area, extending the measurements up to 1018 eV, are discussed.