Depth of the maximum of extensive air showers and mass composition of primary cosmic radiation at an energy of 4 × 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 × 10 17 eV and a zenith angle of θ = 35°. 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 × 10 17 eV is estimated at X max = 655 ± 13 g/cm 2 . Estimates of themass content of primary radiation that were obtained from an analysis of the distribution of X max are compatible with the hypothesis that the role of light nuclei becomes more pronounced at energies above 10 17 eV.