Ultra-high energy cosmic rays: 40 years retrospective of continuous observations at the Yakutsk array: Part 2. Mass composition of cosmic rays at ultra high energies
Yu. G. Shafer Institute of cosmophysical Research and Aeronomy, 31 Lenin ave, Yakutsk, Russia
Published online: 4 August 2015
In the paper, we describe methods for the analysis and present results for the mass composition of cosmic rays, obtained by using these techniques over a large time span. The data were obtained at the Small Cherenkov array over a 20 – year period of continuous observation and 40 – years of observations at the main Yakutsk array. Our experimental data indicate a change in the mass composition in the energy range 1016–1018 eV and is confirmed by independent results obtained by other EAS arrays.
© Owned by the authors, published by EDP Sciences, 2015
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