KASCADE

KASCADE -Grande (Karlsruhe Shower Core and Array Detector Grande) is an experiment at the Research Centre Karlsruhe. It consists of a ground-based network of 252 detector stations, are measured with the extensive air showers caused by the reaction of high energy cosmic rays with the Earth's atmosphere. The aim of the experiment is in the energy range 1016-1018 eV, the indirect measurement of the mass and energy spectrum of cosmic rays.

KASCADE -Grande is the extension of the original, launched in 1996 KASCADE experiment. The data acquisition of the KASCADE-Grande experiment started in 2003 and officially ended on 30 March 2009.

Survey

The experiment is built on the site of the research center. There is a densely stocked, rectangular core field, which consists of the previous experiment KASCADE. It is embedded in a larger rectangular box with larger distances between the individual detector stations.

The individual stations containing different particle detectors (plastic or liquid scintillators with photomultipliers ), which are sensitive to the muonic and electromagnetic component of extensive air shower. Be measured by each station in each parts of air shower, the measured values ​​are combined centrally in real time and filtered to interesting events. Important local metrics are the number density, arrival time and the muon -to -electron ratio.

In the same area there is also the LOPES experiment. LOPES measures the radio emission of air showers with antennas that are built within the KASCADE-Grande experiment.

Mass and energy determination of the cosmic radiation

The experiment allows the energy and mass of cosmic rays determined only indirectly through their influence on the development of showers and shape. An important pillar of the necessary reconstruction are detailed computer simulations of the processes occurring in the Earth's atmosphere processes that lead to the formation of a specific chill. Since the showers by nature itself fluctuate greatly for identical particles, the reconstruction is possible only on a statistical basis.

Computer simulations

Through extensive computer simulations with the Karlsruhe rain simulator CORSIKA to relations between the measured shower shape on the ground and the mass and energy of the generating primary particle can be produced. One problem here is that the computer simulation has to calculate the reaction of particles with such high energy that they have been by anyone yet high-energy experiment in the world measured so far. To perform the simulation anyway, a selection of extrapolated response models used, but are all based on different assumptions and vary slightly in their predictions. Because of these differences in the models, the reconstructed energy and mass transfers in addition to the statistical uncertainty and uncertainty also a systematic uncertainty.

Reconstruction of the shower shape

In a first step, with the local data of each station reconstructs the shape of the shower. From the slightly varying arrival times of the individual stations, the direction of the primary particle can already determine, as the rain front is perpendicular to the flight direction of the primary particle. The front is also slightly curved: and this curvature is reconstructed from the arrival times. The recorded at the grid points is adapted to a particle from showers center outbound radial density function whose shape was determined from computer simulations.

Reconstruction of the primary

From the data rekonstruktierten showers now the energy and mass of the generating cosmic particle can be derived. The energy is determined by the radial density function, wherein the conversion in turn depends on the simulation results. In order to reconstruct the mass of the muon -to -electron ratio and the front curvature used.