The properties of galactic cosmic rays are investigated with the KASCADE-Grande experiment in the energy range between 10
14 and 10
18
eV. Recent results are discussed. They concern mainly the ...all-particle energy spectrum and the elemental composition of cosmic rays.
► All-particle energy spectrum of cosmic rays between knee and ankle is not a single power law. ► Just above 1016eV the spectrum exhibits a hardening. ► Around 8×1016eV there is a knee-like feature ...in the spectrum.
The energy spectrum of cosmic rays between 1016eV and 1018eV, derived from measurements of the shower size (total number of charged particles) and the total muon number of extensive air showers by the KASCADE-Grande experiment, is described. The resulting all-particle energy spectrum exhibits strong hints for a hardening of the spectrum at approximately 2·1016eV and a significant steepening at ≈8·1016eV. These observations challenge the view that the spectrum is a single power law between knee and ankle. Possible scenarios generating such features are discussed in terms of astrophysical processes that may explain the transition region from galactic to extragalactic origin of cosmic rays.
The KASCADE-Grande experiment Apel, W.D.; Arteaga, J.C.; Badea, A.F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2010, Letnik:
620, Številka:
2
Journal Article
Recenzirano
Odprti dostop
KASCADE-Grande is the enlargement of the KASCADE extensive air shower detector, realized to expand the cosmic ray studies from the previous 10
14–10
17
eV primary energy range to 10
18
eV. This is ...performed by extending the area covered by the KASCADE electromagnetic array from 200×200 to 700×700
m
2 by means of 37 scintillator detector stations of 10
m
2 area each. This new array is named Grande and provides measurements of the all-charged particle component of extensive air showers (
N
ch
), while the original KASCADE array particularly provides information on the muon content
(
N
μ
)
. Additional dense compact detector set-ups being sensitive to energetic hadrons and muons are used for data consistency checks and calibration purposes. The performance of the Grande array and its integration into the entire experimental complex is discussed. It is demonstrated that the overall observable resolutions are adequate to meet the physical requirements of the measurements, i.e. primary energy spectrum and elemental composition studies in the primary cosmic ray energy range of 10
16–10
18
eV.
Previous EAS investigations have shown that for a fixed primary energy the charged particle density becomes independent of the primary mass at certain (fixed) distances from the shower axis. This ...feature can be used as an estimator for the primary energy. We present results on the reconstruction of the primary energy spectrum of cosmic rays from the experimentally recorded S(500) observable (the density of charged particles at a distance of 500 m to the shower core as measured in a plane normal to the shower axis) using the KASCADE-Grande detector array. The KASCADE-Grande experiment is hosted by the Karlsruhe Institute for Technology - Campus North, Karlsruhe, Germany, 110 m a.s.l. and operated by an international collaboration. The obtained primary energy spectrum is presented along with the result of another reconstruction technique presently employed at KASCADE-Grande.
The antenna array 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. The coincident measurements allow us to reconstruct the electric field strength at observation level in dependence of general EAS parameters. In the present work, the lateral distribution of the radio signal in air showers is studied in detail. It is found that the lateral distributions of the electric field strengths in individual EAS can be described by an exponential function. For about 20% of the events a flattening towards the shower axis is observed, preferentially for showers with large inclination angle. The estimated scale parameters
R
0
, describing the slope of the lateral profiles range between 100 and 200
m. No evidence for a direct correlation of
R
0
with shower parameters like azimuth angle, geomagnetic angle, or primary energy can be found. This indicates that the lateral profile is an intrinsic property of the radio emission during the shower development which makes the radio detection technique suitable for large scale applications.
► Using muon tracking we study muon production heights in cosmic ray air showers. ► The sensitivity of this quantity to the primary particle mass and energy is shown. ► The validity of hadronic ...interaction models used in simulations is discussed. ► An estimate of the cosmic ray mass composition in the studied energy range is given
A large area (128
m
2) muon tracking detector, located within the KASCADE experiment, has been built with the aim to identify muons (
E
μ
>
0.8
GeV) and their angular correlation in extensive air showers by track measurements under 18 r.l. shielding. Orientation of the muon track with respect to the shower axis is expressed in terms of the radial and tangential angles, which are the basic tools for all muon investigations with the tracking detector. By means of triangulation the muon production height is determined. Distributions of measured production heights are compared to CORSIKA shower simulations. Analysis of these heights reveals a transition from light to heavy cosmic ray primary particles with increasing shower energy in the energy region of the ‘Knee’ of the cosmic ray spectrum
Aims. We wish to study the spectral dependence of the radio emission from cosmic-ray air showers around $100~{\rm PeV}$ $(10^{17}~{\rm eV})$. 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. The radio data are digitally beam-formed before the spectra are determined by sub-band filtering and fast Fourier transformation. Results. The resulting electric field spectra fall off to higher frequencies. An average electric field spectrum is fitted with an exponential $E_{\nu}=K\cdot\mbox{exp}\,(\nu/\mathrm{MHz}/\beta)$ and $\beta=-0.017\pm0.004$, or alternatively, with a power law $\epsilon_{\nu}=K\cdot\nu^{\alpha}$ and a spectral index of $\alpha=-1\pm0.2$. 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). For the analyzed sample of LOPES events, we do not find any significant dependence of the spectral slope on the electric field amplitude, the azimuth angle, the zenith angle, the curvature radius, nor on the average distance of the antennae from the shower core position. But one of the strongest events was measured during thunderstorm activity in the vicinity of LOPES and shows the longest pulse length measured of $110~\mathrm{ns}$ and a spectral slope of $\alpha=-3.6$. 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.
Aims. We want to understand the emission mechanism of radio emission from air showers to determine the origin of high-energy cosmic rays. Therefore, we study the geometry of the air shower radio ...emission measured with LOPES and search for systematic effects between the direction determined on the radio signal and the direction provided by the particle detector array KASCADE. Methods. We produce 4D radio images on time-scales of nanoseconds using digital beam-forming. Each pixel of the image is calculated for three spatial dimensions and as a function of time. The third spatial dimension is obtained by calculating the beam focus for a range of curvature radii fitted to the signal wave front. We search this multi-dimensional parameter space for the direction of maximum coherence of the air shower radio signal and compare it to the direction provided by KASCADE. Results. The maximum radio emission of air showers is obtained for curvature radii being larger than 3 km. We find that the direction of the emission maximum can change when optimizing the curvature radius. This dependence dominates the statistical uncertainty for the direction determination with LOPES. Furthermore, we find a tentative increase of the curvature radius to lower elevations, where the air showers pass through a larger atmospheric depth. The distribution of the offsets between the directions of both experiments is found to decrease linearly with increasing signal-to-noise ratio. Significantly increased offsets and enhanced signal strengths are found in events which were modified by strong electric fields in thunderstorm clouds. Conclusions. We conclude that the angular resolution of LOPES is sufficient to determine the direction which maximizes the observed electric field amplitude. However, the statistical uncertainty of the directions is not determined by the resolution of LOPES, but by the uncertainty of the curvature radius. We do not find any systematic deviation between the directions determined from the radio signal and from the detected particles. This result places a strong supportive argument for the use of the radio technique to study the origin of high-energy cosmic rays.
Latest results and perspectives of the KASCADE-Grande EAS Facility Haungs, A.; Apel, W.D.; Arteaga-Velázquez, J.C. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2012, Letnik:
662
Journal Article
Recenzirano
KASCADE-Grande is a multi-detector experiment at KIT (Karlsruhe Institute of Technology) in Germany for measuring extensive air showers in the primary energy range of 100
TeV to 1
EeV. This paper ...does not provide a synopsis of all results of the KASCADE-Grande experiment. Rather it is focused on three aspects of current interests illustrating the advantages of a multi-detector facility. Results on the analysis of individual energy spectra of primary mass groups around the knee obtained by unfolding the shower size measurements of KASCADE with the help of the new hadronic interaction model EPOS and the all-particle energy spectrum at higher energies obtained by Grande measurements will be discussed. As KASCADE-Grande serves also as host of the LOPES radio detection experiment where both experiments measure the same showers, special emphasis will be given in comparing the characteristics and feasibility of both techniques in estimating the main parameters of high-energy primary cosmic rays: energy, composition, and arrival direction.
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