Optimal Method for Studying Cosmic Rays at Ultrahigh Energies

A method is proposed for determining the energy dependence of the nuclear composition of cosmic rays by studying the trunks of extensive air showers using X-ray emulsion cameras. The novelty of the method lies in the creation of a specialized high-altitude installation and an algorithm for comparing events in and X-ray emulsion chamber with extensive atmospheric showers. The problem of matching is related to the lack of time selection in X-ray emulsion chambers. The combination of emulsion and shower events allows for the creation of a new type of high-altitude installation that is most sensitive to the energy dependence of the composition of cosmic rays. The comparison is carried out statistically. Within the framework of the proposed algorithm, an estimate of the background proportion in the compared events was obtained. The method has been tested when analyzing the events of the ADRON experiment in Tien Shan. It is shown that the background in the statistics of the compared events is no more than 15%. Two semiannual and two annual exposures of each 162 m2 X-ray emulsion chamber were carried out.