γ-families with halos observed by X-ray emulsion chamber in EAS and the estimate of the p+He fraction in primary cosmic rays at E0 = 1–100 PeV

Abstract

The experimental γ-families in which events called "halos" were detected using Xray emulsion chambers (XRECs) of the PAMIR experiment are described. The halo nature is explained within the standard model of nuclear interactions. Based on events with halo, the fraction of p+He in primary cosmic rays (PCR) was estimated. It is shown that the PCR mass composition remains mixed in the range E 0 = 1-100 PeV.