The Depth of Maximum Shower Development and Its Fluctuations: Cosmic Ray Mass Composition at E<sub>0</sub> &ge; 10<sup>17</sup> eV

1 Jul 2010, 13:20
15m
One West (Fermilab)

One West

Fermilab

PO Box 500 Batavia, IL 60510
Contributed Experiments above the Ankle Experiments above the Ankle

Speaker

Dr Stanislav Knurenko (Yu. G. Shafer Institute of cosmophysical research and aeronomy, SB RAS)

Description

We present a new data on Cherenkov light observations obtained during 1994-2009 period, after a modernization of the Yakutsk EAS array. A complex analysis of x_{max} and its fluctuations \sigma(x_{max}) was performed in a wide energy range. With the new data, accord- ing to QGSJet II model, an estimation was made of cosmic rays mass composition for E_0 \sim 10^{17} - 3 \times 10^{19} eV. The result points towards a mixed composition with a large portion of heavy nuclei at E_{0} \sim 10^{17} eV and the dominance of light nuclei at E_{0} \sim 1019 eV. The analysis of \sigma(x_max) 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.
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Primary author

Dr Stanislav Knurenko (Yu. G. Shafer Institute of cosmophysical research and aeronomy, SB RAS)

Co-author

Mr Artem Sabourov (Yu. G. Shafer Institute of cosmophysical research and aeronomy, SB RAS)

Presentation materials