Investigating the 2nd knee: The KASCADE-Grande experiment

Recent results from the multi-detector set-up KASCADE on measurements of cosmic rays in the energy range of the so called "first" knee (at ≈ 3 PeV) indicate a distinct knee in the energy spectra of light primary cosmic rays and an increasing dominance of heavy ones towards higher energies. This leads to the expectation of knee-like features of the heavy primaries at around 100 PeV. To investigate this energy region KASCADE has recently been extended by a factor 10 in area to the new experiment KASCADE-Grande. Main results of KASCADE as well as set-up, capabilities, and status of KASCADE-Grande are presented.