%0 Journal Article
%T The depth of maximum shower development and its fluctuations: cosmic ray mass composition at E0¡Ý1017 eV
%A S. P. Knurenko
%A A. Sabourov
%J Astrophysics and Space Sciences Transactions (ASTRA)
%D 2011
%I 
%R 10.5194/astra-7-251-2011
%X We present new data on Cherenkov light observations obtained during 1994¨C2009 period, after a modernization of the Yakutsk EAS array. A complex analysis of xmax and its fluctuations ¦Ò(xmax) was performed in a wide energy range. With the new data, according to QGSJet II model, an estimation was made of cosmic rays mass composition for E0~1017¨C3¡Á1019 eV. The result points towards a mixed composition with a large portion of heavy nuclei at E0~1017 eV and the dominance of light nuclei at E0~1019 eV. The analysis of ¦Òxmax energy dependence for the same energies qualitatively confirms this result. A shape of xmax distribution at fixed energy 1018 eV is analysed to make more precise conclusion on cosmic ray mass composition.
%U http://www.astrophys-space-sci-trans.net/7/251/2011/astra-7-251-2011.html