The knee of cosmic rays — news from KASCADE

摘要

The energy spectrum of cosmic rays, following over large energy ranges a simple power law, steepens at energies around 4 PeV. This so-called knee is believed to be an imprint of corresponding steepenings or even cut-offs in the energy spectra of single cosmic ray elements, thus implying a change of composition in the range between 1 PeV and 100 PeV. One of the sophisticated experiments aiming at detailed measurements in the knee region is the KASCADE experiment and its successor, KASCADE-Grande. In the following, existing data on the knee and their limitations are briefly discussed. Concluding, an update on the KASCADE composition analysis is presented.