Extensive air showers measured by the KASCADE-Grande experiment
at the Forschungszentrum Karlsruhe are studied with respect
to the arrival times of electrons and muons at observation
level. KASCADE-Grande is a ground based detector array to study
extensive air showers generated by primary cosmic ray particles
in the energy range from 10^14 eV to 10^18 eV.
Approximately 290,000 air showers measured between January 2005
and Febuary 2006 are used to generate arrival time distributions
of electrons and muons for 13 intervals of the distance R to the
shower center. The particle arrival times are reconstructed
by unfolding detector signal pulses sampled by a Flash-ADC based data
system connected to the electron and muon detectors of eight
detector stations of the KASCADE detector array.
For distances R>200 m particles of the a
muonic shower component arrive on average earlier at
observation level than particles of the electromagnetic shower
component. This difference in arrival time is used
to determine a cut on the particle arrival time as a function
of the distance from the shower center. This cut is intended
to be used by experiments with time resolving detectors
for the separation of electrons and muons according to their
arrival times relative to the arrival time of the shower core.
Particles with arrival times smaller than the cut are
considered as muons.
Due to the large spread of the arrival time distributions
the number of muons reconstructed in this way will contain
a contribution from the electromagnetic shower component.
For each separation cut value the purity of the reconstructed
muon sample is determined.