Tunka-133: Results of 3 year operation

Abstract

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.

Results from Tunka-133 (5 years observation) and from the Tunka-HiSCORE prototype

“…EAS maximum depth is derived from two parameters -the steepness of the amplitudedistance function (ADF) and the pulse width at a core distance of 400 m (400) [8].…”

Primary spectrum and composition with IceCube/IceTop

“…This behavior reflects the fact that proton shower penetrate more deeply than iron showers for a given primary energy. When the H4a model of composition is used, the spectra obtained at the four different zenith angles Figure 4: Energy spectrum from the knee to the EeV from three years of IceTop [7] compared to a pure power law (solid line) and to data from KASCADE-Grande [8] and TUNKA [9].…”

“…The IceTop 3-year data are shown along with data from KASCADE-Grande [8] and TUNKA [9] in Fig. 4 compared to an E −3 differential power law shown by the solid line.…”

Parametric analysis of cherenkov light LDF from EAS for high energy gamma rays and nuclei: Ways of practical application

“…Below we present the statistical analysis of a core position resolution. For that purpose instead of the lateral distribution function, Q(R), we applied the fit to the so called 'amplitude-distance function', A(R) [9], which is the maximal value of the Cherenkov pulse rather than the total number of photons in the pulse. This variable is more robust and less disturbed by the noise, so it leads to better results in the core position estimation.…”

“…In the HiSCORE experiment the method a e-mail: abeershehatamahmoud@yahoo.com b e-mail: evgeny.post@gmail.com c e-mail: tfl10@mail.ru of event reconstruction was primarily developed for the Tunka-133 wide angle Cherenkov array [12] at energies above the PeV-range. A special piecewise fitting function [9,12,13] (referred below as the 'Tunka fit'), composed of 4 pieces, was designed to fit both smooth and sharp LDF. The total number of parameters of all constituent functions was reduced to two: a and bx y, the first one is a normalization factor, the second one characterizes the steepness of the whole LDF.…”