Cosmic Ray Energy Spectrum and Mass Composition from 10^15 to 10^17 eV by Data of the Tunka EAS Cherenkov Array

TL;DR

This paper analyzes cosmic ray data from the Tunka-25 array to improve energy spectrum and mass composition estimates between 10^15 and 10^17 eV using new fitting functions and methods for EAS maximum position determination.

Contribution

It introduces a new Cherenkov light LDF fitting function based on CORSIKA simulations and compares two methods for estimating the EAS maximum position.

Findings

Primary energy spectrum from 10^15 to 10^17 eV presented.

New LDF fitting function improves analysis accuracy.

Discussion on using EAS maximum depth for mass composition.

Abstract

We present results of an improved analysis of the experimental data of the EAS Cherenkov array Tunka-25. A new function to fit the Cherenkov light lateral distribution LDF at core distances from 0 to 350 m has been developed on the base of CORSIKA simulations and applied to the analysis of Tunka data. Two methods to estimate the EAS maximum position have been used. The one is based on the pulse FWHM, the other on the light LDF. We present the primary energy spectrum in the energy range 10^15 - 10^17 eV. The use of the depth of the EAS maximum to determine the mean mass composition is discussed.