An investigation of mass composition of ultra-high energy cosmic rays with energies above [10.sup.19] eV via the study of extensive air showers

• Published in: Serbian astronomical journal. no. 184; p. 87
• Main Authors: Doostmohammadi, S, Fatemi, S.J
• Format: Journal Article
• Language: English
• Published: Astronomical Observatory of Belgrade 01.01.2012
• Subjects: Cosmic rays; Dynamics of a particle; Observations
• ISSN: 1450-698X
• DOI: 10.2298/SAJ1284087D

The electron and muon components of extensive air shower (EAS) with energies above 101 eV are analyzed via various giant EAS arrays. A varying property of showers is observed for two energy ranges; higher and lower than (3 - 4) X [10.sup.19] eV. The age parameter, zenith angle, shower size dependence on muon size and shower size dependence on primary energy show an increment of mass composition (MC) above (3 - 4) X [10.sup.19] eV. Comparison of the observed EAS results with the simulations of Capdevielle et al. (2000) and Shinozaki et al. (2005) gives at most 20% photon fraction for primary energies above 1019 eV. The arrival directions of showers above 4 X [10.sup.19] eV indicate an increasing concentration towards the super galactic plane. Key words. cosmic rays [TEXT NOT REPRODUCIBLE IN ASCII]