Energy spectrum and elemental composition of cosmic rays in the PeV region

KASCADE (KArlsruhe Shower Core and Array DEtector) is determining flux spectra for different primary mass groups to disentangle the knee feature of the primary cosmic-ray energy spectrum. The energy spectra of the light element groups result in a knee-like bending and a steepening above the knee. The topology of the individual knee positions suggests a rigidity dependence. To proof the rigidity dependence the KASCADE array is now extended by a factor 10 in area. The major goal of KASCADE- Grande is the observation of the 'iron-knee' in the cosmic-ray spectrum at around 100 PeV which is expected following the KASCADE observations.