56 research outputs found
A high-precision interpolation method for pulsed radio signals from cosmic-ray air showers
Analysis of radio signals from cosmic-ray induced air showers has been shown to be a reliable method to extract shower parameters such as primary energy and depth of shower maximum. The required detailed air shower simulations take 1 to 3 days of CPU time per shower for a few hundred antennas. With nearly 60,000 antennas envisioned to be used for air shower studies at the Square Kilometre Array (SKA), simulating all of these would come at unreasonable costs. We present an interpolation algorithm to reconstruct the full pulse time series at any position in the radio footprint, from a set of antennas simulated on a polar grid. Relying on Fourier series representations and cubic splines, it significantly improves on existing linear methods. We show that simulating about 200 antennas is sufficient for high-precision analysis in the SKA era, including e.g. interferometry which relies on accurate pulse shapes and timings. We therefore propose the interpolation algorithm and its implementation as a useful extension of radio simulation codes, to limit computational effort while retaining accuracy
Depth of shower maximum and mass composition of cosmic rays from 50 PeV to 2 EeV measured with the LOFAR radio telescope
We present an updated cosmic-ray mass composition analysis in the energy
range to eV from 334 air showers measured with the
LOFAR radio telescope, and selected for minimal bias. In this energy range, the
origin of cosmic rays is expected to shift from galactic to extragalactic
sources. The analysis is based on an improved method to infer the depth of
maximum of extensive air showers from radio measurements and air
shower simulations.
We show results of the average and standard deviation of versus
primary energy, and analyze the -dataset at distribution level to
estimate the cosmic ray mass composition. Our approach uses an unbinned maximum
likelihood analysis, making use of existing parametrizations of -distributions per element. The analysis has been repeated for three main
models of hadronic interactions.
Results are consistent with a significant light-mass fraction, at best fit
to protons plus helium, depending on the choice of hadronic
interaction model. The fraction of intermediate-mass nuclei dominates. This
confirms earlier results from LOFAR, with systematic uncertainties on now lowered to 7 to .
We find agreement in mass composition compared to results from Pierre Auger
Observatory, within statistical and systematic uncertainties. However, in line
with earlier LOFAR results, we find a slightly lower average . The
values are in tension with those found at Pierre Auger Observatory, but agree
with results from other cosmic ray observatories based in the Northern
hemisphere.Comment: 24 pages, 14 figures. Accepted for publication in Phys. Rev.
A high-precision interpolation method for pulsed radio signals from cosmic-ray air showers
Analysis of radio signals from cosmic-ray induced air showers has been shown
to be a reliable method to extract shower parameters such as primary energy and
depth of shower maximum. The required detailed air shower simulations take 1 to
3 days of CPU time per shower for a few hundred antennas. With nearly
antennas envisioned to be used for air shower studies at the Square Kilometre
Array (SKA), simulating all of these would come at unreasonable costs. We
present an interpolation algorithm to reconstruct the full pulse time series at
any position in the radio footprint, from a set of antennas simulated on a
polar grid. Relying on Fourier series representations and cubic splines, it
significantly improves on existing linear methods. We show that simulating
about 200 antennas is sufficient for high-precision analysis in the SKA era,
including e.g. interferometry which relies on accurate pulse shapes and
timings. We therefore propose the interpolation algorithm and its
implementation as a useful extension of radio simulation codes, to limit
computational effort while retaining accuracy.Comment: 19 pages, 12 figures. Submitted for publication in JINST (Journal of
Instrumentation
Constraining the cosmic-ray mass composition by measuring the shower length with SKA
The current generation of air shower radio arrays has demonstrated that the atmospheric depth of the shower maximum Xmax can be reconstructed with high accuracy. These experiments are now contributing to mass composition studies in the energy range where a transition from galactic to extragalactic cosmic-ray sources is expected. However, we are still far away from an unambiguous interpretation of the data. Here we propose to use radio measurements to derive a new type of constraint on the mass composition, by reconstructing the shower length L. The low-frequency part of the Square Kilometer Array will have an extremely high antenna density of roughly 60.000 antennas within one square kilometer, and is the perfect site for high-resolution studies of air showers. In this contribution, we discuss the impact of being able to reconstruct L, and the unique contribution that SKA can make to cosmic-ray science.</p
Constraining the cosmic-ray mass composition by measuring the shower length with SKA
The current generation of air shower radio arrays has demonstrated that the
atmospheric depth of the shower maximum Xmax can be reconstructed with high
accuracy. These experiments are now contributing to mass composition studies in
the energy range where a transition from galactic to extragalactic cosmic-ray
sources is expected. However, we are still far away from an unambiguous
interpretation of the data. Here we propose to use radio measurements to derive
a new type of constraint on the mass composition, by reconstructing the shower
length L. The low-frequency part of the Square Kilometer Array will have an
extremely high antenna density of roughly 60.000 antennas within one square
kilometer, and is the perfect site for high-resolution studies of air showers.
In this contribution, we discuss the impact of being able to reconstruct L, and
the unique contribution that SKA can make to cosmic-ray science.Comment: Proceedings 9th International Workshop on Acoustic and Radio EeV
Neutrino Detection Activities - ARENA2022, 7-10 June 2022, Santiago de
Compostela, Spain (8 pages
Constraining the cosmic-ray mass composition by measuring the shower length with SKA
The current generation of air shower radio arrays has demonstrated that the atmospheric depth of the shower maximum Xmax can be reconstructed with high accuracy. These experiments are now contributing to mass composition studies in the energy range where a transition from galactic to extragalactic cosmic-ray sources is expected. However, we are still far away from an unambiguous interpretation of the data. Here we propose to use radio measurements to derive a new type of constraint on the mass composition, by reconstructing the shower length L. The low-frequency part of the Square Kilometer Array will have an extremely high antenna density of roughly 60.000 antennas within one square kilometer, and is the perfect site for high-resolution studies of air showers. In this contribution, we discuss the impact of being able to reconstruct L, and the unique contribution that SKA can make to cosmic-ray science.</p
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