943 research outputs found
Introducing TAXI: a Transportable Array for eXtremely large area Instrumentation studies
A common challenge in many experiments in high-energy astroparticle physics
is the need for sparse instrumentation in areas of 100 km2 and above, often in
remote and harsh environments. All these arrays have similar requirements for
read-out and communication, power generation and distribution, and
synchronization. Within the TAXI project we are developing a transportable,
modular four-station test-array that allows us to study different approaches to
solve the aforementioned problems in the laboratory and in the field.
Well-defined interfaces will provide easy interchange of the components to be
tested and easy transport and setup will allow in-situ testing at different
sites. Every station consists of three well-understood 1 m2 scintillation
detectors with nanosecond time resolution, which provide an air shower trigger.
An additional sensor, currently a radio antenna for air shower detection in the
100 MHz band, is connected for testing and calibration purposes. We introduce
the TAXI project and report the status and performance of the first TAXI
station deployed at the Zeuthen site of DESY.Comment: 4 pages, 3 figures, presented at ARENA 2014, Annapolis, MD, June 201
Optical Relative Calibration and Stability Monitoring for the Auger Fluorescence Detector
The stability of the fluorescence telescopes of the Pierre Auger Observatory
is monitored with the optical relative calibration setup. Optical fibers
distribute light pulses to three different diffuser groups within the optical
system. The total charge per pulse is measured for each pixel and compared with
reference calibration measurements. This allows monitoring the short and long
term stability with respect of the relative timing between pixels and the
relative gain for each pixel. The designs of the LED calibration unit (LCU) and
of the Xenon flash lamp used for relative calibration, are described and their
capabilities to monitor the stability of the telescope performances are
studied. We report the analysis of relative calibration data recorded during
2004. Fluctuations in the relative calibration constants provide a measure of
the stability of the FD.Comment: 4 pp. To appear in the proceedings of 29th International Cosmic Ray
Conference (ICRC 2005), Pune, India, 3-11 Aug 200
Joint Elastic Side-Scattering Lidar and Raman Lidar Measurements of Aerosol Optical Properties in South East Colorado
We describe an experiment, located in south-east Colorado, USA, that measured
aerosol optical depth profiles using two Lidar techniques. Two independent
detectors measured scattered light from a vertical UV laser beam. One detector,
located at the laser site, measured light via the inelastic Raman
backscattering process. This is a common method used in atmospheric science for
measuring aerosol optical depth profiles. The other detector, located
approximately 40km distant, viewed the laser beam from the side. This detector
featured a 3.5m2 mirror and measured elastically scattered light in a bistatic
Lidar configuration following the method used at the Pierre Auger cosmic ray
observatory. The goal of this experiment was to assess and improve methods to
measure atmospheric clarity, specifically aerosol optical depth profiles, for
cosmic ray UV fluorescence detectors that use the atmosphere as a giant
calorimeter. The experiment collected data from September 2010 to July 2011
under varying conditions of aerosol loading. We describe the instruments and
techniques and compare the aerosol optical depth profiles measured by the Raman
and bistatic Lidar detectors.Comment: 34 pages, 16 figure
Tunka-Rex: the Cost-Effective Radio Extension of the Tunka Air-Shower Observatory
Tunka-Rex is the radio extension of the Tunka cosmic-ray observatory in
Siberia close to Lake Baikal. Since October 2012 Tunka-Rex measures the radio
signal of air-showers in coincidence with the non-imaging air-Cherenkov array
Tunka-133. Furthermore, this year additional antennas will go into operation
triggered by the new scintillator array Tunka-Grande measuring the secondary
electrons and muons of air showers. Tunka-Rex is a demonstrator for how
economic an antenna array can be without losing significant performance: we
have decided for simple and robust SALLA antennas, and we share the existing
DAQ running in slave mode with the PMT detectors and the scintillators,
respectively. This means that Tunka-Rex is triggered externally, and does not
need its own infrastructure and DAQ for hybrid measurements. By this, the
performance and the added value of the supplementary radio measurements can be
studied, in particular, the precision for the reconstructed energy and the
shower maximum in the energy range of approximately eV. Here
we show first results on the energy reconstruction indicating that radio
measurements can compete with air-Cherenkov measurements in precision.
Moreover, we discuss future plans for Tunka-Rex.Comment: Proceeding of UHECR 2014, Springdale, Utah, USA, accepted by JPS
Conference Proceeding
Third Level Trigger for the Fluorescence Telescopes of the Pierre Auger Observatory
The trigger system for the Auger fluorescence telescopes is implemented in
hard- and software for an efficient selection of fluorescence light tracks
induced by high-energy extensive air showers. The algorithm of the third stage
uses the multiplicity signal of the hardware for fast rejection of lightning
events with above 99% efficiency. In a second step direct muon hits in the
camera and random triggers are rejected by analyzing the space-time correlation
of the pixels. The trigger algorithm was tested with measured and simulated
showers and implemented in the electronics of the fluorescence telescopes. A
comparison to a prototype trigger without multiplicity shows the superiority of
this approach, e.g. the false rejection rate is a factor 10 lower.Comment: 8 pages, 7 figures, to be published in NIM A; 1 typo correcte
Confronting models on cosmic ray interactions with particle physics at LHC energies
Inelastic pp collisions are dominated by soft (low momentum transfer) physics
where perturbative QCD cannot be fully applied. A deep understanding of both
soft and semi-hard processes is crucial for predictions of minimum bias and
underlying events of the now coming on line pp Large Hadron Collider (LHC).
Moreover, the interaction of cosmic ray particles entering in the atmosphere is
extremely sensitive to these soft processes and consequently cannot be
formulated from first principles. Because of this, air shower analyses strongly
rely on hadronic interaction models, which extrapolate collider data several
orders of magnitude. A comparative study of Monte Carlo simulations of pp
collisions (at the LHC center-of-mass energy ~ 14 TeV) using the most popular
hadronic interaction models for ultrahigh energy cosmic ray (SIBYLL and QGSJET)
and for collider physics (the PYTHIA multiparton model) is presented. The most
relevant distributions are studied including those observables from diffractive
events with the aim of discriminating between the different models.Comment: 8 pages revtex, 8 figures, added reference
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