Study of relative arrival time distributions of electron and muon components measured in the KASCADE central detector

The central detector of the KASCADE experiment contains, apart from a plane of 456 scintillation detectors used as trigger generators, another plane of 50 scintillation detectors (top cluster). The trigger plane allows measurements of arrival times of EAS muons with an energy threshold of E_#mu# >0.4 GeV. The top cluster measures charged particles and their arrival times. Muons with an energy threshold of 2 GeV are able to be selected with multwire proportional chambers (MWPC) under the hadron calorimeter. Because of the telescope-like structure of the detectors, muons seen in the top cluster can be separated from the electromagnetic pulses. Thus arrival times are examined separately for electrons, charged particles (electrons and muons) and muons with two energy thresholds. The observed temporal structure of the shower profiles (position and dispersion) and mainly the relative temporal distance of the different particle components (electrons, muons) are studied. The dependence on EAS-parameters recorded by the KASCADE array (distance to the shower center, shower size, zenith angle) and on the longitudinal shower development are examined. The measured data are compared with detailed Monte Carlo simulations of air shower development and detector characteristics. The experimental data show good agreement with the results from air shower simulations with the CORSIKA program. The arrival time difference of the electron and muon component shows a dependence on the distance to the shower center, however no visible dependence on the cosmic ray primary mass. Monte Carlo simulations indicate that the arrival time differences are practically insensitive to details of the longitudinal shower development. (orig.)