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تسجيل مستخدم جديدRadio detection of air showers with the ARIANNA experiment on the Ross Ice Shelf
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The ARIANNA hexagonal radio array (HRA) is an experiment in its pilot phase designed to detect cosmogenic neutrinos of energies above 10^16 eV. The most neutrino-like background stems from the radio emission of air showers. This article reports on dedicated efforts of simulating and detecting the signals of cosmic rays. A description of the fully radio self-triggered data-set, the properties of the detected air shower signals in the frequency range of unit[100-500]{MHz} and the consequences for neutrino detection are given. 38 air shower signals are identified by their distinct waveform characteristics, are in good agreement with simulations and their signals provide evidence that neutrino-induced radio signals will be distinguishable with high efficiency in ARIANNA. The cosmic ray flux at a mean energy of $6.5^{+1.2}_{-1.0}times10^{17}$ eV is measured to be $1.1^{+1.0}_{-0.7}times10^{-16}$ eV$^{-1}$km$^{-2}$sr$^{-1}$yr$^{-1}$ and one five-fold coincident event is used to illustrate the capabilities of the ARIANNA detector to reconstruct arrival direction and energy of air showers.
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Radio detection of extensive air showers initiated in the Earths atmosphere has made tremendous progress in the last decade. Today, radio detection is routinely used in several cosmic-ray observatories. The physics of the radio emission in air shower
s is well-understood, and analysis techniques have been developed to determine the arrival direction, the energy and an estimate for the mass of the primary particle from the radio measurements. The achieved resolutions are competitive with those of more traditional techniques. In this article, I shortly review the most important achievements and discuss the potential for future applications.
We report on a measurement of thermal neutrons, generated by the hadronic component of extensive air showers (EAS), by means of a small array of EN-detectors developed for the PRISMA project (PRImary Spectrum Measurement Array), novel devices based o
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Radio-glaciological parameters from Moores Bay, in the Ross Ice Shelf, have been measured. The thickness of the ice shelf in Moores Bay was measured from reflection times of radio-frequency pulses propagating vertically through the shelf and reflecti
ng from the ocean, and is found to be $576pm8$ m. Introducing a baseline of 543$pm$7 m between radio transmitter and receiver allowed the computation of the basal reflection coefficient, $R$, separately from englacial loss. The depth-averaged attenuation length of the ice column, $<L >$ is shown to depend linearly on frequency. The best fit (95% confidence level) is $<L( u) >= (460pm20)-(180pm40) u$ m (20 dB/km), for the frequencies $ u=$[0.100-0.850] GHz, assuming no reflection loss. The mean electric-field reflection coefficient is $sqrt{R}=0.82pm0.07$ (-1.7 dB reflection loss) across [0.100-0.850] GHz, and is used to correct the attenuation length. Finally, the reflected power rotated into the orthogonal antenna polarization is less than 5% below 0.400 GHz, compatible with air propagation. The results imply that Moores Bay serves as an appropriate medium for the ARIANNA high energy neutrino detector.
Precise measurements of the radio emission by cosmic ray air showers require an adequate treatment of noise. Unlike to usual experiments in particle physics, where noise always adds to the signal, radio noise can in principle decrease or increase the
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Installation of the ARIANNA Hexagonal Radio Array (HRA) on the Ross Ice Shelf of Antarctica has been completed. This detector serves as a pilot program to the ARIANNA neutrino telescope, which aims to measure the diffuse flux of very high energy neut
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