We present new data on Cherenkov light observations obtained during the period 1994-2009, after a modernization of the Yakutsk EAS array. A complex analysis of \xmax and its fluctuations σ(\xmax) was performed over a wide energy range. With the new data, according to QGSJet II model, an estimation was made of the cosmic ray mass composition for \E∼1017−3×1019 eV. The result points towards a mixed composition with a large portion of heavy nuclei at \E∼1017 eV and the dominance of light nuclei at \E∼1019 eV. The analysis of σ(\xmax) energy dependence for the same energies qualitatively confirms this result. The shape of the \xmax distribution at fixed energy 1018 eV is analysed to make more precise conclusions on cosmic ray mass composition.
@article{arxiv.1010.1185,
title = {The depth of maximum shower development and its fluctuations: cosmic ray mass composition at E_0 >= 10^17 eV},
author = {S. P. Knurenko and A. Sabourov},
journal= {arXiv preprint arXiv:1010.1185},
year = {2015}
}
Comments
Contributed paper to the XVI International Symposium on Very High Energy Cosmic Ray Interactions ISVHECRI 2010, Batavia, IL, USA (28 June - 2 July 2010). 4 pages, 5 figures