Abstract :
Munte Carlo simulations show that the pulse profile of Cerenkov photons measured near the core of an extensive air shower is sensitive to the secondary muon/electron ratio of the cascade. Cerenkov pulses can easily be measured with a single large area mirror viewed by a photomulliplier tube subtending a small field of view (~1^0). Even for such a simple experiment. exposed to EAS from a range of core locations and arrival directions, strong statistical differences are shown to exist between the pulse parameter distributions of primary protons and those of heavier primary particles. A range of primary energies can be investigated by varying the zenith angle of observations. In this paper, results from simulations of primaries in the energy range 20 TeV to 400 TeV are presented, although in principle the technique could be extended to include the knee of the spectrum. At the lower end of this energy range results can he compared to direct measurements of the composition, while measurements at the upper end can augment results from existing ground based experiments.
