ARRIVAL TIME DISTRIBUTIONS OF MUONS FROM EXTENSIVE AIR SHOWERS AS SIGNATURE OF THE MASS COMPOSITION OF COSMIC-RAYS

The central detector of the KASCADE experiment which is intended to st udy the main components of EAS will be equipped with a trigger and fas t timing facility which will enable measurements of the arrival time d istributions of the muons. In particular, at larger distances from the shower axis the arrival time distributions are expected to map the lo ngitudinal development of the showers in the atmosphere and may provid e additional information about the nature of the primary particle thro ugh differences between the mean free paths and the interaction cross sections with air nuclei. We have investigated this aspect with respec t to the KASCADE set-up on the basis of EAS simulations using the Mont e Carlo code CORSIKA. The mean arrival time distributions of muons, ob served at various distances from the shower core and for different pri mary energies and showers sizes, respectively, have been analysed with advanced statistical techniques, based on Bayes decision rules and no n-parametric multivariate analysing methods, in order to specify the m erits of the mean arrival time information of the muon component as a signature for the mass composition of cosmic rays. It turns out that m uon arrival time distributions, observed with the KASCADE facility, ex hibit promising features and mass discrimination effects for larger sh ower sizes, i.e. higher primary energies, around 10(16) eV.