arXiv subjects

J. Bluemer

Publications and source records attributed to J. Bluemer.

28 records · Page 2Linked to original sources

arXiv2008

Applying Shower Development Universality to KASCADE Data

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.

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arXiv2008

Amplitude calibration of a digital radio antenna array for measuring cosmic ray air showers

Radio pulses are emitted during the development of air showers, where air showers are generated by ultra-high energy cosmic rays entering the Earth's atmosphere. These nanosecond short pulses are presently investigated by various experiments for the purpose of using them as a new detection technique for cosmic particles. For an array of 30 digital radio antennas (LOPES experiment) an absolute amplitude calibration of the radio antennas including the full electronic chain of the data acquisition system is performed, in order to estimate absolute values of the electric field strength for these short radio pulses. This is mandatory, because the measured radio signals in the MHz frequency range have to be compared with theoretical estimates and with predictions from Monte Carlo simulations to reconstruct features of the primary cosmic particle. A commercial reference radio emitter is used to estimate frequency dependent correction factors for each single antenna of the radio antenna array. The expected received power is related to the power recorded by the full electronic chain. Systematic uncertainties due to different environmental conditions and the described calibration procedure are of order 20%.

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arXiv2006

New p+C data in fixed target experiments and the muon component in extensive air showers

The interpretation of extensive air shower (EAS) measurements is strongly dependent on the hadronic interaction models used for simulating reference showers. We study the importance of low-energy hadronic interactions in simulated air showers, generated with the simulation package CORSIKA, for the observed characteristics of extensive air showers. In particular we investigate in detail the energy and the phase space regions of secondary particle production which are most important for muon production. This phase space region is covered by fixed target experiments at CERN. In the second part of this work we present preliminary momentum spectra of secondary pi+ and pi- in p+C collisions at 12 GeV/c measured with the HARP spectrometer at the PS accelerator at CERN. In addition we use the new p+C NA49 data at 158 GeV/c to check the reliability of hadronic interaction models for muon production in EAS. Finally, possibilities to measure relevant quantities of hadron production in existing and planned accelerator experiments are discussed.

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arXiv2006

Impact of Varying Atmospheric Profiles on Extensive Air Shower Observation: Fluorescence Light Emission and Energy Reconstruction

Several experiments measure the fluorescence light produced by extensive air showers in the atmosphere. This light is converted into a longitudinal shower profile from which information on the primary energy and composition is derived. The fluorescence yield, as the conversion factor between light profile measured by EAS experiments and physical interpretation of showers, has been measured in several laboratory experiments. The results, however, differ considerably. In this article, a model calculation of the fluorescence emission from relevant band systems of nitrogen in dependence on wavelength and atmospheric conditions is presented. Different calculations are compared to each other in combination with varying input parameters. The predictions are compared with measurements and the altitude-dependence of the fluorescence yield is discussed in detail.

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arXiv2005

Muon production in extensive air showers and its relation to hadronic interactions

In this work, the relation between muon production in extensive air showers and features of hadronic multiparticle production at low energies is studied. Using CORSIKA, we determine typical energies and phase space regions of secondary particles which are important for muon production in extensive air showers and confront the results with existing fixed target measurements. Furthermore possibilities to measure relevant quantities of hadron production in existing and planned accelerator experiments are discussed.

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arXiv2005

Atmospheric Profiles at the Southern Pierre Auger Observatory and their Relevance to Air Shower Measurement

The dependence of atmospheric conditions on altitude and time have to be known at the site of an air shower experiment for accurate reconstruction of extensive air showers and their simulations. The height-profile of atmospheric depth is of particular interest as it enters directly into the reconstruction of longitudinal shower development and of the primary energy and mass of cosmic rays. For the southern part of the Auger Observatory, the atmosphere has been investigated in a number of campaigns with meteorological radio soundings and with continuous measurements of ground-based weather stations. Focussing on atmospheric depth and temperature profiles, temporal variations are described and monthly profiles are developed. Uncertainties of the monthly atmospheres that are currently applied in the Auger reconstruction are discussed.

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arXiv2005

Impact of a new Cherenkov light parameterisation on the reconstruction of shower profiles from Auger hybrid data

The light signal measured by fluorescence telescopes receives - strongly depending on the shower geometry with respect to the detector - a non-negligible contribution from additionally produced Cherenkov light. This Cherenkov contribution has to be accounted for to determine primary parameters properly. In comparison to the previous ansatz used by other experiments, the impact of a new analytical description of Cherenkov light production in EAS on the Auger event reconstruction is investigated.

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arXiv2005

Hadronic multiparticle production in extensive air showers and accelerator experiments

Using CORSIKA for simulating extensive air showers, we study the relation between the shower characteristics and features of hadronic multiparticle production at low energies. We report about investigations of typical energies and phase space regions of secondary particles which are important for muon production in extensive air showers. Possibilities to measure relevant quantities of hadron production in existing and planned accelerator experiments are discussed.

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arXiv2005

Sensitivity of the EDELWEISS WIMP search to spin-dependent interactions

The EDELWEISS collaboration is searching for WIMP dark matter using natural Ge cryogenic detectors. The whole data set of the first phase of the experiment contains a fiducial exposure of 4.8 kg.day on Ge-73, the naturally present (7.8%), high-spin Ge isotope. The sensitivity of the experiment to the spin-dependent WIMP-nucleon interactions is evaluated using the model-independent framework proposed by Tovey et al.

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arXiv2004

Impact of Varying Atmospheric Profiles on Extensive Air Shower Observation: - Atmospheric Density and Primary Mass Reconstruction -

The longitudinal profile of extensive air showers is sensitive to the energy and type/mass of the primary particle. One of its characteristics, the atmospheric depth of shower maximum, is often used to reconstruct the elemental composition of primary cosmic rays. In this article, the impact of the atmospheric density profile on the reconstruction of the depth of maximum, as observed in fluorescence light measurements, is investigated. We consider in detail the atmospheric density profile and its time variations at the site of the southern Pierre Auger Observatory, using data that were obtained from meteorological radio soundings. Similar atmospheric effects are expected to be found also at other sites.

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