Origin of hump in lateral distribution of Cherenkov photon density generated by gamma cosmic ray and study of its characteristics

Energetic secondary particles in gamma and hadron initiated showers can generate Cherenkov photons. Using CORSIKA code and simulation data, different characteristics of lateral distribution of Cherenkov photon density are studied. In particular, physical origin of these differences and also dependence of this distribution on primary energy and altitude of observation level are discussed. It is shown that the existence of a hump in lateral distribution of Cherenkov photon density in gamma initiated showers is a useful tool for separating gamma-hadron and rejecting hadron background in gamma ray astronomy.