Contributions to the 29th international cosmic ray conference, Pune, India, 2005 by Forschungszentrum Karlsruhe : Institut für Kernphysik and Universität Karlsruhe Institut für Experimentelle Kernphysik

Abstract

This report is a compilation of contributions of institutes of the Forschungszentrum Karlsruhe and University Karlsruhe to the International Cosmic Ray Conference (ICRC) held in Pune, India this year. These contributions have been made in close collaboration with many national and international universities and institutes. The compilation provides a review of the corresponding scientific activities of the issuing institutes. It also gives an overview of the status and scientific results of the air shower experiments KASCADE-Grande, the Pierre Auger Project, and the new radio antenna array LOPES, which is complemented by a number of articles on related physics subjects such as air shower simulation and direct cosmic ray measurements. The scientific results presented in these articles have been obtained within and with the support of the Centre of Excellence for Particle and Astroparticle Physics (CETA, http://www.ceta.uni-karlsruhe.de/) and the Virtual Institute for High-Energy Radiation from the Cosmos (VIHKOS, http://www-ik.fzk.de/∼vihkos/). VIHKOS is an association of 2 Helmholtz research centres, 3 Max Planck institutes and 13 universities with the aim of supporting the interaction and integration of research centres and universities for the investigation of astrophysical questions related to cosmic ray physics. KASCADE-Grande (KArisruhe Shower Core and Array DEtector with the extension Grande) is a multi-detector set-up on the site of the Forschungszentrum Karlsruhe. The different detector systems allow the reconstruction of a large set of observables for each measured air shower providing comprehensive information for the analyses. The main aim of the experiment is the determination of the primary energy spectrum and mass composition of cosmic rays in the knee region, i.e. at primary energies of 100 TeV - 1 EeV. The results of the initial experiment KASCADE establish the fact that the knee at a few PeV is dominated by light primaries, whereas the flux of heavy primaries shows no knee in the energy region up to 50 PeV. The extension of KASCADE to KASCADE-Grande for measurements of cosmic rays in the energy region above 50 PeV up to 1 EeV lead to first results after one year of data taking, which were presented at the conference. The LOPES project addresses investigation of radio emission from extensive air showers with the aim to establish this detection technique as a suitable new method for measuring high-energy cosmic rays. LOPES consists of an array of 30 dipole antennas which measure in the frequency range of 40 to 80 MHz in coincidence with KASCADE-Grande. First, very promising experimental results as well as theoretical studies of the possible emission processes in the radio frequency range were reported at the ICRC 2005. The southern part of the Pierre Auger Observatory is presently under construction in the Province Mendoza, Argentina. It will consist of a 3000 km 2 array of 1600 water Cherenkov detectors and 24 fluorescence telescopes. The Auger experiment is designed to measure cosmic rays of ultra-high energy, e.g. above 10 EeV with the aim of investigating the energy spectrum, type and origin of these elusive particles. The Karlsruhe research groups are mainly involved in the construction of the fluorescence detectors, including the DAQ electronics and in data analysis. Reports of the first results underline the unique capabilities of the Auger observatory. Contributions of the Karlsruhe groups discuss the monitoring atmospheric conditions as well as various data analysis aspects ranging from the search for photons at ultra-high energy over fluorescence signal calculations to various approximations for the Cherenkov light emission of air showers. The contributions of the Karlsruhe groups to the ICRC 2005 also include reports on recent additions, improvements of the CORSIKA (COsmic Ray Simulation for Kascade and Auger) simulation package and model tests by comparing their predictions with accelerator data. .