CHERENKOV LIGHT SHAPE OF GAMMA AND HADRONIC VHE AIR SHOWERS - FIT TO ANALYTICAL FORMULAS

A detailed Monte Carlo simulation of Cherenkov light (300-480 nm) from electromagnetic and hadronic cascades in the atmosphere has been perf ormed in the energy range 10(12)-10(14) eV of gamma, proton, oxygen, a nd iron primary cosmic rays for vertically incident showers. In the ca lculations of both cascade development and Cherenkov light production, the CORSIKA (COsmic Ray SImulator for KAscade) code [J.N. Capdevielle et al., Kerforschungszentrum Karlsruhe GmbH, Repr. KfK 4998 (1992)] h as been used to allow for all, electromagnetic and hadronic, interacti ons. The main aim of our simulation is to obtain possibly accurate inf ormation on the lateral spread, longitudinal development, and temporal profile of Cherenkov light, from both pure electromagnetic and hadron ic cascades, in order to obtain information to separate both. Time pro file Cherenkov light pulse and primary cosmic ray dependence have been obtained. Parametrization of Cherenkov light pulses has been performe d making use of gamma distributions. Apart from their value as new res ults, they may be used for the design, of current studies at mountain altitude. We also seek to provide relations to interpret the experimen tal data, for those who do not have detailed simulation calculations a vailable.