633 research outputs found
The cosmic ray muon charge ratio. Measurements and calculations at energies relevant for the atmospheric neutrino anomaly
Simulation of Atmospheric Muon and Neutrino Fluxes with CORSIKA
The fluxes of atmospheric muons and neutrinos are calculated by a three
dimensional Monte Carlo simulation with the air shower code CORSIKA using the
hadronic interaction models DPMJET, VENUS, GHEISHA, and UrQMD. For the
simulation of low energy primary particles the original CORSIKA has been
extended by a parametrization of the solar modulation and a microscopic
calculation of the directional dependence of the geomagnetic cut-off functions.
An accurate description for the geography of the Earth has been included by a
digital elevation model, tables for the local magnetic field in the atmosphere,
and various atmospheric models for different geographic latitudes and annual
seasons. CORSIKA is used to calculate atmospheric muon fluxes for different
locations and the neutrino fluxes for Kamioka. The results of CORSIKA for the
muon fluxes are verified by an extensive comparison with recent measurements.
The obtained neutrino fluxes are compared with other calculations and the
influence of the hadronic interaction model, the geomagnetic cut-off and the
local magnetic field on the neutrino fluxes is investigated.Comment: revtex, 19 pages, 19 Postscript figures, submitted to Phys. Rev.
Flux of atmospheric muons: Comparison between AIRES simulations and CAPRICE98 data
We report on a comparison between the flux of muons in the atmosphere
measured by the CAPRICE98 experiment and simulations performed with the air
shower simulation program AIRES. To reduce systematic uncertainties we have
used as input the primary fluxes of protons and helium nuclei also measured by
the CAPRICE98 experiment. Heavy nuclei are also taken into account in the
primary flux, and their contribution to the muon flux is discussed. The results
of the simulations show a very good agreement with the experimental data, at
all altitudes and for all muon momenta. With the exception of a few isolated
points, the relative differences between measured data and simulations are
smaller than 20 %; and in all cases compatible with zero within two standard
deviations. The influence of the input cosmic ray flux on the results of the
simulations is also discussed. This report includes also an extensive analysis
of the characteristics of the simulated fluxes.Comment: Accepted for publication in Physical Review
Features of arrival time and angle-of-incidence distributions of EAS muons
Charakteristika und Abhängigkeiten von Ankunftszeit- und Einfallswinkelverteilungen von Myonen ausgedehnter Luftschauer
Verschiedene charakteristische Eigenschaften und Korrelationen von Ankunftszeit- und Einfallswinkelverteilungen von Myonen ausgedehnter Luftschauer (EAS) werden untersucht auf der Grundlage von Monte-Carlo Simulationen der EAS Entwicklung mit Hilfe des Simulations-Codes CORSIKA. Die Ankunftszeitverteilungen und Winkel-verteilungen werden charakterisiert durch die Ankunftszeit bzw. Einfallswinkel des ersten Myons, durch Mittelwerte und Median-Werte der Verteilungen in den einzelnen Schauern.
Spezielles Augenmerk wird gerichtet auf Vielfach-Korrelationen bei gleichzeitigen Beobachtungen in verschiedenen Abständen vom Schauer-Zentrum. Es wird gezeigt, daß ein solcher Beobachtungsmode zusätzliche Informationen zur Verbesserung der Unterscheidung der Art der Primärteilchen liefert
Inner structure of the Puy de Dˆome volcano: cross-comparison of geophysical models (ERT, gravimetry, muon imaging)
International audienceMuon imaging of volcanoes and of geological structures in general is actively being developed by several groups in the world. It has the potential to provide 3-D density distributions with an accuracy of a few percent. At this stage of development, comparisons with established geophysical methods are useful to validate the method. An experiment has been carried out in 2011 and 2012 on a large trachytic dome, the Puy de Dˆome volcano, to perform such a comparison of muon imaging with gravimetric tomography and 2-D electrical resistivity tomography. Here, we present the preliminary results for the last two methods. North-south and east-west resistivity profiles allow us to model the resistivity distribution down to the base of the dome. The modelling of the Bouguer anomaly provides models for the density distribution within the dome that are directly comparable with the results from the muon imaging. Our ultimate goal is to derive a model of the dome using the joint interpretation of all sets of data
Energy loss of pions and electrons of 1 to 6 GeV/c in drift chambers operated with Xe,CO2(15%)
We present measurements of the energy loss of pions and electrons in drift
chambers operated with a Xe,CO2(15%) mixture. The measurements are carried out
for particle momenta from 1 to 6 GeV/c using prototype drift chambers for the
ALICE TRD. Microscopic calculations are performed using input parameters
calculated with GEANT3. These calculations reproduce well the measured average
and most probable values for pions, but a higher Fermi plateau is required in
order to reproduce our electron data. The widths of the measured distributions
are smaller for data compared to the calculations. The electron/pion
identification performance using the energy loss is also presented.Comment: 15 pages, 10 figures, accepted for publication in Nucl.Instrum.Meth.
Space charge in drift chambers operated with the Xe,CO2(15%) mixture
Using prototype modules of the ALICE Transition Radiation Detector we
investigate space charge effects and the dependence of the pion rejection
performance on the incident angle of the ionizing particle. The average pulse
height distributions in the drift chambers operated with the Xe,CO2(15%)
mixture provide quantitative information on the gas gain reduction due to space
charge accumulating during the drift of the primary ionization. Our results
demonstrate that the pion rejection performance of a TRD is better for tracks
which are not at normal incidence to the anode wires. We present detailed
simulations of detector signals, which reproduce the measurements and lend
strong support to our interpretation of the measurements in terms of space
charge effects.Comment: 18 pages, 10 figures, accepted for publication in Nucl.Instrum.Meth.
A. Data files available at http://www-alice.gsi.de/tr
Air shower simulation for background estimation in muon tomography of volcanoes
International audienceOne of the main sources of background for the radiography of volcanoes using atmospheric muons comes from the accidental coincidences produced in the muon telescopes by charged particles belonging to the air shower generated by the primary cosmic ray. In order to quantify this background effect, Monte Carlo simulations of the showers and of the detector are developed by the TOMUVOL collaboration. As a first step, the atmospheric showers were simulated and investigated using two Monte Carlo packages, CORSIKA and GEANT4.We compared the results provided by the two programs for the muonic component of vertical proton-induced showers at three energies: 1, 10 and 100 TeV. We found that the spatial distribution and energy spectrum of the muons were in good agreement for the two codes
Transition Radiation Spectra of Electrons from 1 to 10 GeV/c in Regular and Irregular Radiators
We present measurements of the spectral distribution of transition radiation
generated by electrons of momentum 1 to 10 GeV/c in different radiator types.
We investigate periodic foil radiators and irregular foam and fiber materials.
The transition radiation photons are detected by prototypes of the drift
chambers to be used in the Transition Radiation Detector (TRD) of the ALICE
experiment at CERN, which are filled with a Xe, CO2 (15 %) mixture. The
measurements are compared to simulations in order to enhance the quantitative
understanding of transition radiation production, in particular the momentum
dependence of the transition radiation yield.Comment: 18 pages, 15 figures, submitted to Nucl. Instr. Meth. Phys. Res.
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