Forschungszentrum Karlsruhe

A system of large-area position-sensitive multiwire proportional chambers (MWPC), installed below the hadron calorimeter of the central detector of the KASCADE (KArlsruhe Shower Core and Array DEtector) experiment is able to observe the density distributions of high-energy muons and of the high-energy tails of the hadron spectrum in the core of extensive air showers (EAS). Applying a classification by multifractal moments of the observed patterns allows to explore the information on mass composition of cosmic rays in the studied energy region. Additionally correlating with the shower size and the number of reconstructed muons in the core region, an artificial neural net analysis leads to probability distributions for associating single showers to particular primary masses. The classification can serve as basis of a more detailed shower specification considering further measured shower parameters

Experimental Investigations of the Time Structure of the EAS Muon Component

The time structure of the Extended Air Shower (EAS) muon component, rather directly mapping the longitudinal shower development, is studied at sea level by measurements of the muon arrival time distributions using the muon detection facilities of the KASCADE central detector. Data have been analysed for EAS core distances up to 130 m for primary energies of the knee region. Results are presented for the distributions of various moments and the dispersion of the arrival times relative to the arrival time of the foremost muon, respectively. For the muon observations at larger core distances particular studies could be performed with the question to which extent EAS muon arrival time distributions display features with information about the mass composition of the primary cosmic rays. The present exploratory attempt is based on Linsley's approach of an indirect determination of the elongation rate and of the fluctuations of the height of the shower maximum