Search

The evolution of the muon content of very high energy air showers (EAS) in the atmosphere is investigated with data of the KASCADE-Grande observatory. For this purpose, the muon attenuation length in the atmosphere is obtained to Λ μ = 1256 ± 85 − 232 + 229 ( syst ) g/cm 2 from the experimental data for shower energies between 10 16.3 and 10 17.0  eV. Comparison of this quantity with predictions of the high-energy hadronic interaction models QGSJET-II-02, SIBYLL 2.1, QGSJET-II-04 and EPOS-LHC reveals that the attenuation of the muon content of measured EAS in the atmosphere is lower than predicted. Deviations are, however, less significant with the post-LHC models. The presence of such deviations seems to be related to a difference between the simulated and the measured zenith angle evolutions of the lateral muon density distributions of EAS, which also causes a discrepancy between the measured absorption lengths of the density of shower muons and the predicted ones at large distances from the EAS core. The studied deficiencies show that all four considered hadronic interaction models fail to describe consistently the zenith angle evolution of the muon content of EAS in the aforesaid energy regime. [ABSTRACT FROM AUTHOR]

The energy reconstruction at KASCADE-Grande is based on a combination of the shower size and the total muon number, which are both estimated for each individual air shower event. We present investigations where we employed a second method to reconstruct the primary energy using S (500), which are the charged particle densities inferred with the KASCADE-Grande detector at a distance of 500 m from the shower axis. We considered the attenuation of inclined showers by applying the “Constant Intensity Cut” method and we employed a simulation-derived calibration to convert the recorded S (500) into primary energy. We observed a systematic shift in the S (500)-derived energy compared with previously reported results obtained using the standard reconstruction technique. However, a comparison of the two methods based on simulated and measured data showed that this shift only appeared in the measured data. Our investigations showed that this shift was caused mainly by the inadequate description of the shape of the lateral density distribution in the simulations. [ABSTRACT FROM AUTHOR]

The KASCADE-Grande large area (128 m 2 ) Muon Tracking Detector has been built with the aim to identify muons ( E μ thr = 800 MeV) in Extensive Air Showers by track measurements under 18 r.l. shielding. This detector provides high-accuracy angular information (approx. 0.3 ° ) for muons up to 700 m distance from the shower core. In this work we present the lateral density distributions of muons in EAS measured with the Muon Tracking Detector of the KASCADE-Grande experiment. The density is calculated by counting muon tracks in a muon-to-shower-axis distance range from 100 m to 610 m from showers with reconstructed energy of 10 16 – 10 17 eV and zenith angle θ < 18 ° . In the distance range covered by the experiment, these distributions are well described by functions phenomenologically determined already in the fifties (of the last century) by Greisen. They are compared also with the distributions obtained with the KASCADE scintillator array ( E μ thr = 230 MeV) and with distributions obtained using simulated showers. [ABSTRACT FROM AUTHOR]

Abstract: Previous results obtained by KASCADE-Grande using the QGSjetII-02 hadronic interaction model have shown that the energy spectrum of cosmic rays between eV and eV exhibits a significant hardening at approximately eV and a slight but statistically significant steepening close to eV. Moreover, the analysis with QGSjetII-02 suggests that the break observed around eV is caused by the heavy component of primary cosmic rays. In this paper, we report on the results of similar analyses performed using the SIBYLL 2.1 and EPOS 1.99 hadronic interaction models to interpret the data. The present results confirm qualitatively the previous findings. However, the intensity of the all-particle spectrum, the positions of the hardening and steepening of the spectrum, as well as the relative abundance of the heavy and light mass groups depend on the hadronic interaction model used to interpret the data. [Copyright &y& Elsevier]

Abstract: The KASCADE-Grande experiment operated at KIT from January 2004 to November 2012, measuring EAS generated by primary cosmic rays in the 1016–1018 eV energy range. The experiment detected, for each single event, with a high resolution, the total number of charged particles (N ch ) and of muons ( ). In this contribution we present the latest results about: [(i)] The measurement of the all particle energy spectrum, discussing the influence of the hadronic interaction model used to derive the energy calibration of the experimental data. [(ii)] The energy spectra derived separating the events according to the ratio. This technique allowed us to unveil a steepening of the spectrum of heavy primaries at and a hardening of the spectrum of light primaries at . [(iii)] The elemental spectra (for five mass groups) obtained applying a detailed unfolding analysis technique. [(iv)] A search for large scale anisotropies. [Copyright &y& Elsevier]

Highlights: [•] We compare LOPES radio lateral distributions of air showers with simulations. [•] Absolute amplitude is reproduced by REAS 3.11 simulations, but lower for CoREAS. [•] Slope of measured lateral distributions is reproduced by both simulation programs. [•] Rarely measured rising lateral distributions are likely due to refractive index of air. [•] The lateral distribution is sensitive to energy and mass of the primary particle. [ABSTRACT FROM AUTHOR]

Abstract: The KASCADE-Grande air shower experiment [1] consists of, among others, a large scintillator array for measurements of charged particles, , and of an array of shielded scintillation counters used for muon counting, . KASCADE-Grande is optimized for cosmic ray measurements in the energy range 10PeV to about 2000PeV, where exploring the composition is of fundamental importance for understanding the transition from galactic to extragalactic origin of cosmic rays. Following earlier studies of the all-particle and the elemental spectra reconstructed in the knee energy range from KASCADE data [2], we have now extended these measurements to beyond 200PeV. By analysing the two-dimensional shower size spectrum vs. for nearly vertical events, we reconstruct the energy spectra of different mass groups by means of unfolding methods over an energy range where the detector is fully efficient. The procedure and its results, which are derived based on the hadronic interaction model QGSJET-II-02 and which yield a strong indication for a dominance of heavy mass groups in the covered energy range and for a knee-like structure in the iron spectrum at around 80PeV, are presented. This confirms and further refines the results obtained by other analyses of KASCADE-Grande data, which already gave evidence for a knee-like structure in the heavy component of cosmic rays at about 80PeV [3]. [Copyright &y& Elsevier]

Abstract: To better understand the radio signal emitted by extensive air-showers and to further develop the radio detection technique of high-energy cosmic rays, the LOPES experiment was reconfigured to LOPES-3D. LOPES-3D is able to measure all three vectorial components of the electric field of radio emission from cosmic ray air showers. The additional measurement of the vertical component ought to increase the reconstruction accuracy of primary cosmic ray parameters like direction and energy, provides an improved sensitivity to inclined showers, and will help to validate simulation of the emission mechanisms in the atmosphere. LOPES-3D will evaluate the feasibility of vectorial measurements for large scale applications. In order to measure all three electric field components directly, a tailor-made antenna type (tripoles) was deployed. The change of the antenna type necessitated new pre-amplifiers and an overall recalibration. The reconfiguration and the recalibration procedure are presented and the operationality of LOPES-3D is demonstrated. [Copyright &y& Elsevier]

Abstract: The KASCADE–Grande experiment, located at Karlsruhe Institute of Technology (Germany) is a multi-component extensive air-shower experiment devoted to the study of cosmic rays and their interactions at primary energies 1014–1018 eV. Main goals of the experiment are the measurement of the all-particle energy spectrum and mass composition in the 1016–1018 eV range by sampling charged (N ch ) and muon () components of the air shower. The method to derive the energy spectrum and its uncertainties, as well as the implications of the obtained result, is discussed. An overview of the analyses performed by KASCADE–Grande to derive the mass composition of the measured high-energy comic rays is presented as well. [Copyright &y& Elsevier]

Abstract: The energy spectrum of cosmic rays between 1016 eV and 1018 eV, 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 2·1016 eV and a significant steepening at ≈8·1016 eV. 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. [Copyright &y& Elsevier]

Abstract: Relativistic, charged particles present in extensive air showers (EAS) lead to a coherent emission of radio pulses which are measured to identify the shower initiating high-energy cosmic rays. Especially during thunderstorms, there are additional strong electric fields in the atmosphere, which can lead to further multiplication and acceleration of the charged particles and thus have influence on the form and strength of the radio emission. For a reliable energy reconstruction of the primary cosmic ray by means of the measured radio signal it is very important to understand how electric fields affect the radio emission. In addition, lightning strikes are a prominent source of broadband radio emissions that are visible over very long distances. This, on the one hand, causes difficulties in the detection of the much lower signal of the air shower. On the other hand the recorded signals can be used to study features of the lightning development. The detection of cosmic rays via the radio emission and the influence of strong electric fields on this detection technique is investigated with the LOPES experiment in Karlsruhe, Germany. The important question if a lightning is initiated by the high electron density given at the maximum of a high-energy cosmic-ray air shower is also investigated, but could not be answered by LOPES. But, these investigations exhibit the capabilities of EAS radio antenna arrays for lightning studies. We report about the studies of LOPES measured radio signals of air showers taken during thunderstorms and give a short outlook to new measurements dedicated to search for correlations of lightning and cosmic rays. [Copyright &y& Elsevier]

Abstract: A new method is explored to detect extensive air showers: the measurement of radio waves emitted during the propagation of the electromagnetic shower component in the magnetic field of the Earth. Recent results of the pioneering experiment LOPES are discussed. It registers radio signals in the frequency range between 40 and 80MHz. The intensity of the measured radio emission is investigated as a function of different shower parameters, such as shower energy, angle of incidence, and distance to shower axis. In addition, new antenna types are developed in the framework of LOPESstar and new methods are explored to realize a radio self-trigger algorithm in real time. [Copyright &y& Elsevier]

Abstract: The properties of galactic cosmic rays are investigated with the KASCADE-Grande experiment in the energy range between 1014 and 1018 eV. Recent results are discussed. They concern mainly the all-particle energy spectrum and the elemental composition of cosmic rays. [Copyright &y& Elsevier]

Abstract: A large area (128m2) muon tracking detector, located within the KASCADE experiment, has been built with the aim to identify muons (E μ >0.8GeV) 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 [Copyright &y& Elsevier]

Abstract: KASCADE-Grande is the enlargement of the KASCADE extensive air shower detector, realized to expand the cosmic ray studies from the previous 1014–1017 eV primary energy range to 1018 eV. This is performed by extending the area covered by the KASCADE electromagnetic array from 200×200 to 700×700m2 by means of 37 scintillator detector stations of 10m2 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 . 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 1016–1018 eV. [Copyright &y& Elsevier]

Abstract: 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 , describing the slope of the lateral profiles range between 100 and 200m. No evidence for a direct correlation of 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. [Copyright &y& Elsevier]

LOPES was a digital antenna array detecting the radio emission of cosmic-ray air showers. The calibration of the absolute amplitude scale of the measurements was done using an external, commercial reference source, which emits a frequency comb with defined amplitudes. Recently, we obtained improved reference values by the manufacturer of the reference source, which significantly changed the absolute calibration of LOPES. We reanalyzed previously published LOPES measurements, studying the impact of the changed calibration. The main effect is an overall decrease of the LOPES amplitude scale by a factor of 2.6 ± 0.2, affecting all previously published values for measurements of the electric-field strength. This results in a major change in the conclusion of the paper ‘Comparing LOPES measurements of air-shower radio emission with REAS 3.11 and CoREAS simulations’ published by Apel et al. (2013) : With the revised calibration, LOPES measurements now are compatible with CoREAS simulations, but in tension with REAS 3.11 simulations. Since CoREAS is the latest version of the simulation code incorporating the current state of knowledge on the radio emission of air showers, this new result indicates that the absolute amplitude prediction of current simulations now is in agreement with experimental data. [ABSTRACT FROM AUTHOR]

Abstract: 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 3–5PeV to be caused by a steepening in the light-element spectra [T. Antoni et al., (KASCADE Coll.), Astropart. Phys. 24 (2005) 1–25]. 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. [Copyright &y& Elsevier]

Abstract: On basis of the theorem of a universal shower development stating that a hadronically generated extensive air shower is completely described by the primary energy, the position of the shower maximum and a parameter related to the total muon number, the so-called correlation curve method is developed and applied to KASCADE data. Correlation information of the muon and electron content of showers measured by the KASCADE experiment are used for the reconstruction of energy and mass of primary cosmic rays. Systematic uncertainties of the method and the results are discussed in detail. It is shown that by this method general tendencies in spectrum and composition indeed can be revealed, but the absolute normalization in energy and mass scale requires much more detailed simulations. [Copyright &y& Elsevier]

Abstract: Extensive air showers measured by the KASCADE–Grande experiment at the Forschungszentrum Karlsruhe are studied with respect to the arrival times of electrons and muons at observation level. The mean and the spread of the arrival time distributions have been used to determine the average time profile of the electromagnetic and muonic shower disk. For core distances particles of the muonic shower component arrive on average earlier at observation level than particles of the electromagnetic shower component. The difference increases with the core distance from at to at , where the width of the muonic and electromagnetic shower disks are comparable. This difference in arrival time is used to separate the electrons and muons dependent on the distance from the shower center. This is intended to be used by experiments with time resolving detectors. [Copyright &y& Elsevier]

Abstract: The KASCADE-Grande experiment, located at Forschungszentrum Karlsruhe (Germany), is a multi-component extensive air-shower experiment to study cosmic rays and their interactions at primary energies 1014–1018 eV. After detailed investigations of the knee in the spectrum with KASCADE and EAS-TOP experiments, the main goal of KASCADE-Grande is to provide conclusive results on the knee region by detecting the expected iron knee in the spectrum at around 1017 eV, and measuring the composition in the possible transition region between galactic and extragalactic components. Due to its multi-component characteristics, basically the former KASCADE experiment enriched by two new arrays of scintillator detectors (Grande and Piccolo), with the aim of providing a large acceptance area (0.5km2) and prompt trigger signal, KASCADE-Grande is a suitable array to provide refined measurements in the 1016–1018 eV region. In the following, we briefly report on the characteristics of the detector, its performance, and first results based on 2 years of data taking. [Copyright &y& Elsevier]

Abstract: Data taken during half a year of operation of 10 LOPES antennas (LOPES-10), triggered by EAS observed with KASCADE-Grande have been analysed. We report about the analysis of correlations of radio signals measured by LOPES-10 with extensive air shower events reconstructed by KASCADE-Grande, including shower cores at large distances. The efficiency of detecting radio signals induced by air showers up to distances of 700m from the shower axis has been investigated. The results are discussed with special emphasis on the effects of the reconstruction accuracy for shower core and arrival direction on the coherence of the measured radio signal. In addition, the correlations of the radio pulse amplitude with the primary cosmic ray energy and with the lateral distance from the shower core are studied. [Copyright &y& Elsevier]

Abstract: Lateral distributions for electrons and muons in extensive air showers measured with the array of the KASCADE experiment are compared to results of simulations based on the high-energy hadronic interaction models QGSJet and SIBYLL. It is shown, that the muon distributions are well described by both models. Deviations are found for the electromagnetic component, where both models predict a steeper lateral shape than observed in the data. For both models the observed lateral shapes of the electron component indicate a transition from a light to a more heavy composition of the cosmic ray spectrum above the knee. [Copyright &y& Elsevier]

Abstract: A composition analysis of KASCADE air shower data is performed by means of unfolding the two-dimensional frequency spectrum of electron and muon numbers. Aim of the analysis is the determination of energy spectra for elemental groups representing the chemical composition of primary cosmic rays. Since such an analysis depends crucially on simulations of air showers the two different hadronic interaction models QGSJet and SIBYLL are used for their generation. The resulting primary energy spectra show that the knee in the all particle spectrum is due to a steepening of the spectra of light elements but, also, that neither of the two simulation sets is able to describe the measured data consistently over the whole energy range with discrepancies appearing in different energy regions. [Copyright &y& Elsevier]

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. [Copyright &y& Elsevier]

The KASCADE experiment measures a high number of EAS observables with a large degree of sampling of the electron–photon, muon, and hadron components. It provides accurate data for an event-by-event analysis of the primary cosmic ray flux in the energy range around the knee. The possibility of selecting samples of enriched proton and iron induced extensive air showers by applying the statistical techniques of multivariate analyses is scrutinized using detailed Monte Carlo simulations of three different primaries. The purity and efficiency of the proton and iron classification probability is investigated. After obtaining enriched samples from the measured data by application of the procedures the reconstructed number of hadrons, hadronic energy and other parameters are investigated in the primary energy range 1015–1016 eV. By comparing these shower parameters for purified proton and iron events, respectively, with simulated distributions an attempt is made to check the validity of strong interaction models at high energies. [Copyright &y& Elsevier]

The attenuation of the electron shower size beyond the shower maximum is studied with the KASCADE extensive air shower (EAS) experiment in the primary energy range of about 1014–1016 eV. Attenuation and absorption lengths are determined by applying different approaches, including the method of constant intensity, the decrease of the flux of EASs with increasing zenith angle, and its variation with ground pressure. We observe a significant dependence of the results on the applied method. The determined values of the attenuation length ranges from 175 to 196 g/cm2 and of the absorption length from 100 to 120 g/cm2. The origin of these differences is discussed emphasizing the influence of intrinsic shower fluctuations. [Copyright &y& Elsevier]

In a recent publication Schatz [Astropart. Phys. (2003), this issue] argues that unambiguous results about energy distributions of primary cosmic-ray mass groups can only be obtained from measured air shower observables if their mutual correlations are explicitly taken into account. This statement is used to challenge preliminary results presented by the KASCADE Collaboration at the International Cosmic Ray Conference in Hamburg, 2001 [KASCADE Collaboration, 27th ICRC, Hamburg, 2001, p. 97; KASCADE Collaboration, Invited Rapporteur and Highlight Papers of ICRC 2001, p. 240]. In this comment it is argued that the criticism of Schatz does not apply to the aforementioned analysis of KASCADE data. [Copyright &y& Elsevier]

Abstract: When ultra high energy cosmic rays hit the atmosphere, they produce a shower of millions of secondary particles. Thereby the charged particles in the shower emit a radio pulse whilst deflected in the Earth''s magnetic field. LOPES is a digital antenna array measuring these radio pulses in the frequency range from 40 to 80MHz. It is located at the site of and triggered by the air shower experiment KASCADE-Grande at Karlsruhe Institute of Technology (KIT), Germany. In its present configuration, it consists of 15 east–west-polarized and 15 north–south-polarized, absolutely calibrated short dipole antennas, as well as 10 LPDAs (with two channels each). Furthermore, it serves as a test bench for technological developments, like new antenna types or a radio-based self-triggering (). To achieve a good angular reconstruction and to digitally form a beam into the arrival direction of the shower, it has a precise time calibration. [Copyright &y& Elsevier]

Abstract: Precise measurements of the radio emission by cosmic ray air showers require an adequate treatment of noise. Unlike to usual experiments in particle physics, where noise always adds to the signal, radio noise can in principle decrease or increase the signal if it interferes by chance destructively or constructively. Consequently, noise cannot simply be subtracted from the signal, and its influence on amplitude and time measurement of radio pulses must be studied with care. First, noise has to be determined consistently with the definition of the radio signal which typically is the maximum field strength of the radio pulse. Second, the average impact of noise on radio pulse measurements at individual antennas is studied for LOPES. It is shown that a correct treatment of noise is especially important at low signal-to-noise ratios: noise can be the dominant source of uncertainty for pulse height and time measurements, and it can systematically flatten the slope of lateral distributions. The presented method can also be transferred to other experiments in radio and acoustic detection of cosmic rays and neutrinos. [Copyright &y& Elsevier]

Abstract: 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 100TeV to 1EeV. 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. [Copyright &y& Elsevier]