148 research outputs found
Atmospheric Monitoring for Astroparticle Physics Observatories
For many observatories recording high-energy cosmic rays, gamma rays, or neutrinos, the Earth’s atmosphere is either an integral part or at least a considerable aspect of the detector setup. After giving an overview of the influence of the atmosphere and its variability on the development of the observed particle cascades and the signals detected from them, atmospheric monitoring strategies implemented by the different observatories are described. Examples of the impact of atmospheric parameters and profiles on the core data of these observatories are given and technical aspects of long-term and partially very laborious monitoring efforts of the Earth’s atmosphere are discussed. Due to the per se interdisciplinary character of atmospheric monitoring in astroparticle physics, several new projects beyond the core physics of the astroparticle physics observatories have evolved and some are reviewed in this presentation
Investigation of atmospheric effects on the development of extensive air showers and their detection with the Pierre Auger Observatory
Air Fluorescence Relevant for Cosmic-Ray Detection - Summary of the 5th Fluorescence Workshop, El Escorial 2007
High-energy cosmic rays with energies exceeding eV are frequently
observed by measurements of the fluorescence light induced by air showers. A
major contribution to the systematic uncertainties of the absolute energy scale
of such experiments is the insufficient knowledge of the fluorescence light
yield of electrons in air. The aim of the 5th Fluorescence Workshop was to
bring together experimental and theoretical expertise to discuss the latest
progress on the investigations of the fluorescence light yield. The results of
the workshop will be reviewed as well as the present status of knowledge in
this field. Emphasis is given to the fluorescence light yield important for air
shower observations and its dependence on atmospheric parameters, like
pressure, temperature, and humidity. The effects of the latest results on the
light observed from air showers will be discussed.Comment: Nucl. Instr. & Meth. in pres
Measuring Cloud Base Height and Cloud Coverage using Elastic Multiangle Lidars at Pierre Auger Observatory
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
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