The EAS Cherenkov light array Tunka-133, with $ 3 km 2 geometric area, is taking data since 2009. The array permits a detailed study of cosmic ray energy spectrum and mass composition in the PeV energy range. After a short description of the methods of EAS parameter reconstruction, we present the allparticle energy spectrum and results of studying CR composition, based on 3 seasons of array operation. In the last part of the paper, we discuss possible interpretations of the obtained results.

a b s t r a c tA new EAS Cherenkov light array, Tunka-133, with $ 1 km 2 geometrical area has been installed at the Tunka Valley (50 km from Lake Baikal) in 2009. The array permits a detailed study of cosmic ray energy spectrum and mass composition in the energy range 10 16-10 18 eV with a uniform method. We describe the array construction, DAQ and methods of the array calibration. The method of energy reconstruction and absolute calibration of measurements are discussed. The analysis of spatial and time structure of EAS Cherenkov light allows to estimate the depth of the EAS maximum X max .The results on the all particles energy spectrum and the mean depth of the EAS maximum X max vs. primary energy derived from the data of two winter seasons (2009)(2010)(2011) are presented. Preliminary results of joint operation of the Cherenkov array with antennas for the detection of EAS radio signals are shown. Plans for future upgrades -deployment of remote clusters, radioantennas and a scintillator detector network and a prototype of the HiSCORE gamma-telescope -are discussed.

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