arXiv subjects

B. Wundheiler

Publications and source records attributed to B. Wundheiler.

6 recordsLinked to original sources

arXiv2015

A method to reconstruct the muon lateral distribution with an array of segmented counters with time resolution

Despite the significant experimental effort made in the last decades, the origin of the ultra high energy cosmic rays is still unknown. The chemical composition of these energetic particles carries key astrophysical information to identify where they come from. It is well known that the muon content of the showers generated by the interaction of the cosmic rays with air molecules, is very sensitive to the primary particle type. Therefore, the measurement of the number of muons at ground level is an essential tool to infer the cosmic ray mass composition. We introduce a novel method to reconstruct the lateral distribution of muons with an array of counters buried underground like AMIGA, one of the Pierre Auger Observatory detector systems. The reconstruction builds on a previous method we recently presented by considering the detector time resolution. With the new method more events can be reconstructed than with the previous one. In addition the statistical uncertainty of the measured number of muons is reduced, allowing for a better primary mass discrimination.

astro-ph.IM↗

arXiv2015

Study of the chemical composition of high energy cosmic rays using the muon LDF of EAS between $10^{17.25}$ eV and $10^{17.75}$ eV

We explore the feasibility of estimating primary cosmic ray composition at high energies from the study of two parameters of Extensive Air Showers (EAS) at ground and underground level with Monte Carlo simulations using the new EPOS and QGSJETII hadronic models tuned with LHC data. Namely, the slope and density at a given distance of the muon lateral distribution function are analysed in this work. The power to discriminate primary masses is quantified in terms of merit factor for each parameter. The analysis considers three different primary particles (proton, iron and gamma), four different zenith angles (0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$ and 45$^{\circ}$) and primary energies of $10^{17.25}$ eV, $10^{17.50}$ eV and $10^{17.75}$ eV.

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arXiv2014

Digital Electronics for the Pierre Auger Observatory AMIGA Muon Counters

The "Auger Muons and Infill for the Ground Array" (AMIGA) project provides direct muon counting capacity to the Pierre Auger Observatory and extends its energy detection range down to 0.3 EeV. It currently consists of 61 detector pairs (a Cherenkov surface detector and a buried muon counter) distributed over a 23.5 km2 area on a 750 m triangular grid. Each counter relies on segmented scintillator modules storing a logical train of '0's and '1's on each scintillator segment at a given time slot. Muon counter data is sampled and stored at 320 MHz allowing both the detection of single photoelectrons and the implementation of an offline trigger designed to mitigate multi-pixel PMT crosstalk and dark rate undesired effects. Acquisition is carried out by the digital electronics built around a low power Cyclone III FPGA. This paper presents the digital electronics design, internal and external synchronization schemes, hardware tests, and first results from the Observatory.

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arXiv2013

The lateral shower age parameter as an estimator of chemical composition

We explore the feasibility of estimating primary cosmic ray composition at ultra high energies from the study of lateral age parameter of Extensive Air Showers (EAS) at ground level. Using different types of lateral distribution functions, we fit the particle density of simulated EAS to find the lateral age parameter. We discuss the chemical composition calculating the merit factor for each parameter distribution. The analysis considers three different primary particles (proton, iron and gamma), four different zenith angles (0°, 15°, 30° and 45°) and three primary energies (10^{17.25} eV, 10^{17.50} eV and 10^{17.75} eV).

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arXiv2010

The Pierre Auger Project and Enhancements

The current status of the scientific results of the Auger Observatory will be discussed which include spectrum, anisotropy in arrival directions, chemical composition analyses, and limits on neutrino and photon fluxes. A review of the Observatory detection systems will be presented. Auger has started the construction of its second phase which encompasses antennae for radio detection of cosmic rays, high-elevation telescopes, and surface plus muon detectors. Details will be presented on the latter, AMIGA (Auger Muons and Infill for the Ground Array), an Auger project consisting of 85 detector pairs each one composed of a surface water-Cherenkov detector and a buried muon counter. The detector pairs are arranged in an array with spacings of 433 and 750 m in order to perform a detailed study of the 10^17 eV to 10^19 eV spectrum region. Preliminary results on the performance of the 750 m array of surface detectors and the first muon counter prototype will be presented.

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arXiv2009

First buried muon counter prototype for the Auger Observatory

AMIGA (Auger Muons and Infill for the Ground Array) constitutes an enhancement for the Pierre Auger Observatory. It consists of a denser array of surface detectors and muon counters whose objective is both to extend the detection range down to 10^17 eV and to help towards mass composition determination. The latter is to be achieved with muon counters since the shower muon content is one of the best parameter for particle type identification. In this work, we present the study of a muon counter prototype. The prototype was buried 3 m deep in an effort to avoid signal contamination from the shower electromagnetic component. We study the performance of the detector before and after burying it with its associated electronic components. The detector validation is performed from signal analysis of charged particles traversing the counter.

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