203 research outputs found
Ultrahigh Energy Cosmic Rays Detection
The paper describes methods used for the detection of cosmic rays with
energies above 10^18 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been
anticipated there would be a cutoff in the energy spectrum of primary cosmic
rays around 3 10^19 eV induced by their interaction with the 2.7 K primordial
photons. This has become known as the GZK cutoff. However, several showers have
been detected with estimated primary energy exceeding this limit.Comment: 4 pages, 4 figures. To appear in the proceedings of 17th Conference
on High Energy Physics (IFAE 2005) (In Italian), Catania, Italy, 30 Mar - 2
Apr 200
The ARCADE Raman Lidar System for the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) is the next generation of ground-based
very high energy gamma-ray instruments; the facility will be organized in two
arrays, one for each hemisphere. The atmospheric calibration of the CTA
telescopes is a critical task. The atmosphere affects the measured Cherenkov
yield in several ways: the air-shower development itself, the variation of the
Cherenkov angle with altitude, the loss of photons due to scattering and
absorption of Cherenkov light out of the camera field-of-view and the
scattering of photons into the camera. In this scenario, aerosols are the most
variable atmospheric component in time and space and therefore need a
continuous monitoring. Lidars are among the most used instruments in
atmospheric physics to measure the aerosol attenuation profiles of light. The
ARCADE Lidar system is a very compact and portable Raman Lidar system that has
been built within the FIRB 2010 grant and is currently taking data in Lamar,
Colorado. The ARCADE Lidar is proposed to operate at the CTA sites with the
goal of making a first survey of the aerosol conditions of the selected site
and to use it as a calibrated benchmark for the other Lidars that will be
installed on site. It is proposed for CTA that the ARCADE Lidar will be first
upgraded in Italy and then tested in parallel to a Lidar of the EARLINET
network in L'Aquila. Upgrades include the addition of the water vapour Raman
channel to the receiver and the use of new and better performing electronics.
It is proposed that the upgraded system will travel to and characterize both
CTA sites, starting from the first selected site in 2016
Go to the astroparticle physics school with the Toledo Metro Station Totem-Telescope for cosmic rays
n/
The analog signal processing board for the HEAT telescopes
Abstract The aim of the Pierre Auger Observatory is to measure with high statistics the flux, the arrival directions and the mass composition of cosmic rays at the highest energies. Since 2009, the Auger Collaboration has added three new High Elevation Auger Telescopes (HEAT) along with a new 25 km 2 infill array in the field of view of the new telescopes. These enhancements have lowered the energy threshold of the Observatory by about an order of magnitude. In combination with the existing telescopes in Coihueco the vertical field of view is extended to about 60°, allowing the measurement of nearby air showers arising from primaries with energies as low as 2×10 17 eV. In this paper we describe the new front-end analog board developed to process the signals generated by the photomultipliers of the HEAT telescopes. Eighty analog boards have been produced, fully characterized and tested. The main characteristics of the electronic circuits and the circuit parameters are illustrated
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
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