Estimates of energy of the vertical giant air showers

Abstract

The responses of scintillator detectors to particles of the vertical giant air showers with energies of 10 18 – 10 21 eV have been calculated in terms of the quark–gluon string model. Simulations have been carried out with help of the 5-level scheme. The propagation of the primary particle through the atmosphere have been regarded by the Monte–Carlo method. The transport equations have been used to take into account propagation of high energy secondary particles and to calculate the source functions for the low energy electrons and gamma quanta. The CORSIKA code had been used to spread these low energy particles in the atmosphere above the detector plane and finally the GEANT4 code had been applied to estimate responses of scintillator detectors to particles which strike them. The energies of the primary particles for calculated signals (responses) at 600 m from the shower core have been compared with the energy estimates given by the basic formula which is in current practice at the Yakutsk array for the measured signals of the same values. This basic formula has been confirmed by simulations at energies of 10 18 eV. But at larger signals simulations show larger estimates of energy than the formula gives. Thus estimates of energy of giant air showers calculated with help of the basic formula may be underestimated increasing the Greisen–Zatsepin–Kuzmin enigma.