212 research outputs found
Altitude dependence of fluorescence light emission by extensive air showers
Fluorescence light is induced by extensive air showers while developing in
the Earth's atmosphere. The number of emitted fluorescence photons depends on
the conditions of the air and on the energy deposited by the shower particles
at every stage of the development. In a previous model calculation, the
pressure and temperature dependences of the fluorescence yield have been
studied on the basis of kinetic gas theory, assuming temperature-independent
molecular collision cross-sections. In this work we investigate the importance
of temperature-dependent collision cross-sections and of water vapour quenching
on the expected fluorescence yield. The calculations will be applied to
simulated air showers while using actual atmospheric profiles to estimate the
influence on the reconstructed energy of extensive air showers.Comment: 8 pages, 18 figures, to be published in Proc. 5th Fluorescence
Workshop, El Escorial - Madrid, Sept. 200
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.Comment: 20 pages, 15 figures, 13 tables, accepted for publication in
Astropart. Phy
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.Comment: 21 pages, 5 figures, 4 tables, Astroparticle Physics in pres
First results of the air shower experiment KASCADE
The main goals of the KASCADE (KArlsruhe Shower Core and Array DEtector)
experiment are the determination of the energy spectrum and elemental
composition of the charged cosmic rays in the energy range around the knee at
ca. 5 PeV. Due to the large number of measured observables per single shower a
variety of different approaches are applied to the data, preferably on an
event-by-event basis. First results are presented and the influence of the
high-energy interaction models underlying the analyses is discussed.Comment: 3 pages, 3 figures included, to appear in the TAUP 99 Proceedings,
Nucl. Phys. B (Proc. Suppl.), ed. by M. Froissart, J. Dumarchez and D.
Vignau
2008-2009 President\u27s Report
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Electron, Muon, and Hadron Lateral Distributions Measured in Air-Showers by the KASCADE Experiment
Measurements of electron, muon, and hadron lateral distributions of extensive
air showers as recorded by the KASCADE experiment are presented. The data cover
the energy range from about 5x10^14 eV up to almost 10^17 eV and extend from
the inner core region to distances of 200 m. The electron and muon
distributions are corrected for mutual contaminations by taking into account
the detector properties in the experiment. All distributions are well described
by NKG-functions. The scale radii describing the electron and hadron data best
are approx. 30 m and 10 m, respectively. We discuss the correlation between
scale radii and `age' parameter as well as their dependence on shower size,
zenith angle, and particle energy threshold.Comment: 28 pages, 14 figures, Accepted for publication in Astroparticle
Physic
Dissecting the knee - Air shower measurements with KASCADE
Recent results of the KASCADE air shower experiment are presented in order to
shed some light on the astrophysics of cosmic rays in the region of the knee in
the energy spectrum. The results include investigations of high-energy
interactions in the atmosphere, the analysis of the arrival directions of
cosmic rays, the determination of the mean logarithmic mass, and the unfolding
of energy spectra for elemental groups
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