Depth of the maximum of extensive air showers and mass composition of primary cosmic radiation at an energy of 4 x 1017 eV according to data on radioemission from extensive air showers

The results of a reanalysis of experimental data on extensive-air-shower radioemission that were obtained previously at the Moscow State University array for studying extensive air showers are presented. The lateral distribution of radioemission is given for showers characterized by a primary energy of 4 x 1017 eV and a zenith angle of θ = 35 deg. On the basis of an analysis of a lateral distribution of radioemission, the average value of the shower-maximum depth at a primary energy of 4 x 1017 eV is estimated at Xmax = 655 ± 13 g/cm2. Estimates of themass content of primary radiation that were obtained from an analysis of the distribution of Xmax are compatible with the hypothesis that the role of light nuclei becomes more pronounced at energies above 1017 eV.