50 research outputs found
Radio Emission in Atmospheric Air Showers : Results of LOPES-10
LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from Extensive Air Showers. Data taken during half a year of operation of 10 LOPES antennas (LOPES-10), triggered by showers observed with KASCADE-Grande have been analyzed. We report about results of correlations found of the measured radio signals by LOPES-10 with shower parameters
Energy Spectra of Elemental Groups of Cosmic Rays: Update on the KASCADE Unfolding Analysis
The KASCADE experiment measures extensive air showers induced by cosmic rays
in the energy range around the so-called knee. The data of KASCADE have been
used in a composition analysis showing the knee at 3-5 PeV to be caused by a
steepening in the light-element spectra. Since the applied unfolding analysis
depends crucially on simulations of air showers, different high energy hadronic
interaction models (QGSJet and SIBYLL) were used. The results have shown a
strong dependence of the relative abundance of the individual mass groups on
the underlying model. In this update of the analysis we apply the unfolding
method with a different low energy interaction model (FLUKA instead of GHEISHA)
in the simulations. While the resulting individual mass group spectra do not
change significantly, the overall description of the measured data improves by
using the FLUKA model. In addition data in a larger range of zenith angle are
analysed. The new results are completely consistent, i.e. there is no hint to
any severe problem in applying the unfolding analysis method to KASCADE data.Comment: accepted for publication in Astroparticle Physic
Investigation of the Properties of Galactic Cosmic Rays with the KASCADE-Grande Experiment
The properties of galactic cosmic rays are investigated with the
KASCADE-Grande experiment in the energy range between and
eV. Recent results are discussed. They concern mainly the all-particle energy
spectrum and the elemental composition of cosmic rays.Comment: Proc. RICAP 09, Nucl. Instr. and Meth. in pres
The KASCADE-Grande Experiment and the LOPES Project
KASCADE-Grande is the extension of the multi-detector setup KASCADE to cover
a primary cosmic ray energy range from 100 TeV to 1 EeV. The enlarged EAS
experiment provides comprehensive observations of cosmic rays in the energy
region around the knee. Grande is an array of 700 x 700 sqm equipped with 37
plastic scintillator stations sensitive to measure energy deposits and arrival
times of air shower particles. LOPES is a small radio antenna array to operate
in conjunction with KASCADE-Grande in order to calibrate the radio emission
from cosmic ray air showers. Status and capabilities of the KASCADE-Grande
experiment and the LOPES project are presented.Comment: To appear in Nuclear Physics B, Proceedings Supplements, as part of
the volume for the CRIS 2004, Cosmic Ray International Seminar: GZK and
Surrounding
Cosmic Ray Energy Spectra and Mass Composition at the Knee - Recent Results from KASCADE -
Recent results from the KASCADE experiment on measurements of cosmic rays in
the energy range of the knee are presented. Emphasis is placed on energy
spectra of individual mass groups as obtained from an two-dimensional unfolding
applied to the reconstructed electron and truncated muon numbers of each
individual EAS. The data show a knee-like structure in the energy spectra of
light primaries (p, He, C) and an increasing dominance of heavy ones (A > 20)
towards higher energies. This basic result is robust against uncertainties of
the applied interaction models QGSJET and SIBYLL which are used in the shower
simulations to analyse the data. Slight differences observed between
experimental data and EAS simulations provide important clues for further
improvements of the interaction models. The data are complemented by new limits
on global anisotropies in the arrival directions of CRs and by upper limits on
point sources. Astrophysical implications for discriminating models of maximum
acceleration energy vs galactic diffusion/drift models of the knee are
discussed based on this data.Comment: 8 pages, 7 figures, to appear in Nuclear Physics B, Proceedings
Supplements, as part of the volume for the CRIS 2004, Cosmic Ray
International Seminar: GZK and Surrounding
A new method to measure the attenuation of hadrons in extensive air showers
Extensive air showers are generated through interactions of high-energy
cosmic rays impinging the Earth's atmosphere. A new method is described to
infer the attenuation of hadrons in air showers. The numbers of electrons and
muons, registered with the scintillator array of the KASCADE experiment are
used to estimate the energy of the shower inducing primary particle. A large
hadron calorimeter is used to measure the hadronic energy reaching observation
level. The ratio of energy reaching ground level to the energy of the primary
particle is used to derive an attenuation length of hadrons in air showers. In
the energy range from GeV to GeV the attenuation length
obtained increases from 170 \gcm2 to 210 \gcm2. The experimental results are
compared to predictions of simulations based on contemporary high energy
interaction models.Comment: accepted for publication in Physical Review
Radio detection of cosmic ray air showers with LOPES
In the last few years, radio detection of cosmic ray air showers has
experienced a true renaissance, becoming manifest in a number of new
experiments and simulation efforts. In particular, the LOPES project has
successfully implemented modern interferometric methods to measure the radio
emission from extensive air showers. LOPES has confirmed that the emission is
coherent and of geomagnetic origin, as expected by the geosynchrotron
mechanism, and has demonstrated that a large scale application of the radio
technique has great potential to complement current measurements of ultra-high
energy cosmic rays. We describe the current status, most recent results and
open questions regarding radio detection of cosmic rays and give an overview of
ongoing research and development for an application of the radio technique in
the framework of the Pierre Auger Observatory.Comment: 8 pages; Proceedings of the CRIS2006 conference, Catania, Italy; to
be published in Nuclear Physics B, Proceedings Supplement
Frequency spectra of cosmic ray air shower radio emission measured with LOPES
AIMS: We wish to study the spectral dependence of the radio emission from
cosmic-ray air showers around 100 PeV (1017 eV). METHODS: We observe short
radio pulses in a broad frequency band with the dipole-interferometer LOPES
(LOFAR Prototype Station), which is triggered by a particle detector array
named Karlsruhe Shower Core and Array Detector (KASCADE). LOFAR is the Low
Frequency Array. For this analysis, 23 strong air shower events are selected
using parameters from KASCADE. RESULTS: The resulting electric field spectra
fall off to higher frequencies. An average electric field spectrum is fitted
with an exponential, or alternatively, with a power law. The spectral slope
obtained is not consistent within uncertainties and it is slightly steeper than
the slope obtained from Monte Carlo simulations based on air showers simulated
with CORSIKA (Cosmic Ray Simulations for KASCADE). One of the strongest events
was measured during thunderstorm activity in the vicinity of LOPES and shows
the longest pulse length measured of 110 ns and a spectral slope of -3.6.
CONCLUSIONS: We show with two different methods that frequency spectra from air
shower radio emission can be reconstructed on event-by-event basis, with only
two dozen dipole antennae simultaneously over a broad range of frequencies.
According to the obtained spectral slopes, the maximum power is emitted below
40 MHz. Furthermore, the decrease in power to higher frequencies indicates a
loss in coherence determined by the shower disc thickness. We conclude that a
broader bandwidth, larger collecting area, and longer baselines, as will be
provided by LOFAR, are necessary to further investigate the relation of the
coherence, pulse length, and spectral slope of cosmic ray air showers.Comment: 13 pages, 21 figures. Nigl, A. et al. (LOPES Collaboration),
Frequency spectra of cosmic ray air shower radio emission measured with
LOPES, accepted by A&A on 17/06/200