Using the facilities of the KASCADE Central Detector EAS muon arrival time distributions , observed with reference to the arrival time of the first locally registered muon , and their correlations with other EAS observables have been experimentally

investigated .
The variation of adequately defined time parameters with the distance R _ { \mu } from the EAS axis has been measured .
The experimental data enable a study of the sensitivity of such local arrival time distributions , which characterise the structure of the shower disc , to the mass composition of cosmic rays in the energy region around the knee .
For that purpose , nonparametric multivariate even-by-event analyses have been performed for an estimate of the mass composition specified by three different mass groups , invoking detailed Monte Carlo simulations of the EAS development .
It turns out that local muon arrival time distributions , without information on the curvature of the shower disc , display a minor sensitivity to the mass of the EAS inducing particle , at least for distances from the shower axis R _ { \mu } < 100 m. The measurements comprise a subset of all EAS events registered by KASCADE due to the observation conditions of the arrival time distributions , with a threshold of the muon energy E _ { th } = 2.4 GeV and a minimum multiplicity n _ { th } for being accepted in the observed data samples .
This subset is sensitive to variations of the integral EAS muon energy spectrum .
By studying the event acceptance in the registered samples on basis of Monte Carlo simulations a test of the consistency of the Monte Carlo simulations with the data is enabled , comparing the results inferred from observations at different R _ { \mu } and different n _ { th } values .
Within the present uncertainties the results of such a test show a remarkable agreement of the experimental findings with the Monte Carlo simulations , using the QGSJET model as generator of the high-energy hadronic interactions .