First preliminary results of the balloon-borne experiment SPHERE-2 on the all-nuclei primary cosmic rays (PCR) spectrum and primary composition are presented. The primary spectrum in the energy range 1016--5⋅1017 eV was reconstructed using characteristics of Vavilov-Cherenkov radiation of extensive air showers (EAS), reflected from a snow surface. Several sources of systematic uncertainties of the spectrum were analysed. A method for separation of the primary nuclei' groups based on the lateral distribution function' (LDF) steepness parameter is presented. Preliminary estimate of the mean light nuclei' fraction f30−150 at energies 3⋅1016--1.5⋅1017 eV was performed and yielded f30−150= (21±11)%.
@article{arxiv.1210.1360,
title = {Results on the primary CR spectrum and composition reconstructed with the SPHERE-2 detector},
author = {R. A. Antonov and S. P. Beschapov and E. A. Bonvech and D. V. Chernov and T. A. Dzhatdoev and Mir. Finger and Mix. Finger and V. I. Galkin and N. V. Kabanova and A. S. Petkun and D. A. Podgrudkov and T. M. Roganova and S. B. Shaulov and T. I. Sysoeva},
journal= {arXiv preprint arXiv:1210.1360},
year = {2015}
}
Comments
4 pages, 2 figures, Proc. 23rd European Cosmic Ray Symposium, to appear in J. Phys. Conf. Ser