Showing papers by "J. Scholz published in 2003"

The cosmic-ray experiment KASCADE

Abstract: KASCADE has been designed to measure air showers of primary cosmic-ray energies in the PeV region and to investigate the knee phenomenon in the all-particle energy spectrum. Several observations are measured simultaneously for each event by different detector systems. The experiment started to take data in 1996 and has been completed and extended since then. The individual detector systems and their performances are described. Also, the experience in long-term operation of the experiment and the interplay between different components is outlined.

Energy spectra of cosmic rays in the knee region

Abstract: The key observables of the KASCADE field array are the electron and muon number of extensive air showers. Using the size spectra of these measured quantities and their correlations with energy and primary mass it is possible to reconstruct the energy spectra of individual mass groups. The analysis relies on the application of unfolding methods. The resulting spectra of the light components show a knee-like feature. The positions of the individual knees suggest a dependence on the primary charge even if the statistical and systematical significance has to be improved.

KASCADE extensive air shower experiment

Abstract: The main aim of the KASCADE extensive air shower (EAS) experiment is the determination of the chemical composition of cosmic rays in the energy range around and above the knee at Ek ≈ 3 PeV. A large number of observables are measured simultaneously for each individual event, by the combination of various detection techniques for the electromagnetic, the muonic, and the hadronic component of the extensive air showers. Detailed investigations have been performed with the data measured by the KASCADE experiment since the start of data taking at the end of 1995. The results allow to evaluate hadronic interaction models, used in simulations to interpret air shower data. The all-particle spectrum of cosmic rays and their mass composition, as well as individual spectra for groups of elements have been reconstructed in the energy range between 1015 and 1017 eV . The results suggest, the knee in the all-particle cosmic-ray energy spectrum is caused by a rigidity-dependent cut-off of individual element groups. To improve the statistics around 1017 eV, where the “iron knee” in the cosmic ray spectrum is indicated in our data, the KASCADE experiment has recently been extended to KASCADE-Grande by a large collecting area (0.5km2) electromagnetic array, contributed from the former EAS-TOP experiment. The Grande part will cover the primary energy range 1016 eV

Test of interaction models with the KASCADE hadron calorimeter

Abstract: The interpretation of extensive air shower measurements often requires the comparison with EAS simulations. These calculations rely on hadronic interaction models which have to extrapolate into kinematical and energy regions not covered by present-day collider experiments. The KASCADE experiment with its large hadron calorimeter and its detectors for the electromagnetic and muonic components provides experimental data to check hadronic interaction models. For the EAS simulations the program CORSIKA with several hadronic event generators embedded is used. Different hadronic observables are investigated as well as their correlations with the electromagnetic and muonic components. Comparing the interaction models QGSJET 98, NEXUS II, and DPMJET 11.5, it is found, that QGSJET describes the data best.

Energy Spectrum and Elemental Composition in the PeV Region

Abstract: One of the main aims of KASCADE is the determination of flux spectra for different primary cosmic ray mass groups to disentangle the knee feature The field detector array of the KASCADE experiment measures the electron and muon component of extensive air showers in the knee region with high precision On the basis of these measured data corresponding two-dimensional shower size spectra are investigated On the arbitrary assumption that the chemical composition consists of five primary mass groups the size distributions are deconvoluted to reconstruct the energy spectra of the groups in the energy range between 10 15 eV and 10 17 eV The energy spectrum results in a knee-like bending and a steepening above the knee The topology of the individual knee positions suggests a rigidity dependence 1 Introduction The knowledge of the energy spectra of different components of primary cosmic rays in the knee region is of vital importance for testing alternative hypotheses of the cosmic ray (CR) origin and acceleration The analysis of EAS presented benefits from the simultaneous measurement of different observables for each individual event by the KASCADE experiment [6] Appropriate unfolding procedures, also taking correlations into account, make it possible to deconvo

Muon density spectra as a probe of the muon component predicted by air shower simulations

Abstract: The KASCADE experiment measures local muon densities of air-showers in the knee region at various core distances for two different muon energy thresholds. Muon density spectra have been reconstructed for the total EAS sample, as well as for particular subsamples with enhanced light and heavy induced EAS, classified on the basis of the shower size ratio Nμ/Ne. By comparing these spectra for different muon energy detection thresholds and core distances with detailed Monte Carlo simulations each spectrum should result in the same primary energy spectrum. This allows a comprehensive test of the simulation procedures of the muon lateral distribution and the muon energy spectrum by various Monte Carlo codes. Different combinations of high-energy and low-energy interaction models in the frame of the CORSIKA code are used for comparisons.

Determination of primary energy and mass in the PeV region by Bayesian unfolding techniques

Abstract: The field detector array of the KASCADE experiment measures the electron and muon component of extensive air showers in the knee region with high precision. A baysian unfolding procedure is presented in which the two-dimensional shower size distribution ( N e , N μ tr ) is examined. On the arbitrary assumption that the chemical composition consists of five primary mass groups (hydrogen, helium, carbon, silicon and iron) the size distribution is deconvoluted to reconstruct the energy spectra of these mass groups in the energy range between 10 15 eV and 10 17 eV. The energy spectra of the lighter element groups result in a knee-like bending with a steepening above the knee. The topology of the individual knee positions suggest a rigidity dependence.

On the hadronic component of extensive air showers

Abstract: The hadronic component of extensive air showers is investigated with the large calorimeter of the KASCADE experiment The transverse momentum transfer in EAS is explored by investigations of the geometrical structure in the hadronic shower core and the arrival times of hadrons The flux of unaccompanied hadrons is studied to probe hadronic cross sections The measured results are compatible with simulations using CORSIKA/QGSJET

Muon production heights determined in the KASCADE experiment

Abstract: Muon production heights in EAS provide a specific tool to investigate the longitudinal development of EAS, since muons are little affected by subsequent interactions in the atmosphere. Multiplicity of muons presents also a unique tool to investigate hadronic interaction models. The capability of the Muon Tracking Detector to measure radial and tangential angles of muon tracks in EAS, in combination with the shower direction determined by the Array of the KASCADE experiment, has been investigated. Due to different characteristics in shower development of light and heavy primary cosmic ray particles the radial angle and therefore the related production height is sensitive to the mass of them. Muon production height (MPH) and muon production depth (MPD) were studied in different bins of the muon shower size for measured data and MC simulations, which have been performed using the Monte Carlo program CORSIKA with the hadronic interaction models QGSJet and ne X us . First composition studies on the basis of MPD distributions have been carried out.

Sensitivity and consistency studies of muon arrival time distributions measured by KASCADE

Abstract: Using the facilities of the KASCADE Central Detector EAS muon arrival time distributions, observed with reference to the arrival time of the first locally registered muon, and their correlations with other EAS observables have been investigated at different distances R μ from the shower axis. Invoking detailed Monte Carlo simulations non-parametric multivariate even-by-event analyses have been performed for an estimate of the primary mass composition. The consistency of the Monte Carlo simulations is studied by comparing the primary mass composition results inferred from observations at different R μ and different muon multiplicity thresholds n th .