The Pierre Auger Observatory has already collected more ultra high energy cosmic ray data than all previous experiments. The hybrid detection technique provides results on the energy spectrum and ...arrival directions of the highest energy cosmic rays, and characterize the extensive air showers in order to probe characteristics of the primary particle and its interactions. The Pierre Auger Observatory is also sensitive to ultra high energy neutrinos and photons. In this paper recent results from the Pierre Auger Observatory including a limit on the diffuse flux of neutrinos above 1017 eV and limit on the fraction of photons to the total cosmic ray flux are shown.
The surface detector (SD) array of the Pierre Auger Observatory containing at present 1680 water Cherenkov detectors spread over an area of 3000 km 2 started to operate since 2004. The currently used ...Front-End Boards are equipped with no-more produced ACEX ® and obsolete Cyclone ® FPGA (40 MSps/15-bit of dynamic range). Huge progress in electronics and new challenges from physics impose a significant upgrade of the SD electronics either to improve a quality of measurements (much higher sampling and much wider dynamic range) or pick-up from a background extremely rare events (new FPGA algorithms based on sophisticated approaches like e.g. spectral triggers or neural networks). Much higher SD sensitivity is necessary to confirm or reject hypothesis critical for a modern astrophysics. The paper presents the Front-End Board (FEB) with the biggest Cyclone ® V E FPGA 5CEFA9F31I7N, supporting 8 channels sampled with max. 250 MSps @ 14-bit resolution. Considered sampling for the SD is 120 MSps, however, the FEB has been developed with external anti-aliasing filters to keep a maximal flexibility. Six channels are targeted to the SD, two the rest for other experiments like: Auger Engineering Radio Array and additional muon counters. The FEB is an intermediate design pluged-in the actually used Unified Board (UB) communicating with micro-controller at 40 MHz, however providing even 250 MSPs sampling with 20-bit dynamic range, equipped in a virtual NIOS ® processor and supporting 256 MB of SDRAM as well as with an implemented spectral trigger based on the Discrete Cosine Transform for a detection of very inclined "old" showers. The FEB can also support a neural network developing for a detection of "young" showers, potentially generated by neutrinos.
The observation of ultra-high energy neutrinos (UHEνs) has become a priority in experimental astroparticle physics. Neutrinos can interact in the atmosphere (downward-going ν) or in the Earth crust ...(Earth-skimming ν), producing air showers that can be observed with arrays of detectors at the ground. The surface detector array of the Pierre Auger Observatory can detect these types of cascades. The distinguishing signature for neutrino events is the presence of very inclined showers produced close to the ground (i.e., after having traversed a large amount of atmosphere). Up to now, the Pierre Auger Observatory did not find any candidate on a neutrino event. This imposes competitive limits to the diffuse flux of UHEνs. A very low rate of events potentially generated by neutrinos is a significant challenge for a detection technique and requires both sophisticated algorithms and high-resolution hardware. We present a trigger based on a pipeline artificial neural network implemented in a large FPGA which after learning can recognize traces corresponding to special types of events. The structure of an artificial neural network (ANN) algorithm being developed on the MATLAB platform has been implemented into the fast logic of the biggest FPGA from the Cyclone V E family used for the prototype of the Front-End Board (FEB) for the Auger-Beyond-2015. Several algorithms were tested, however, the Levenberg-Marquardt one (trainlm) seems to be the most efficient. The network was taught: a) to recognize "old" showers (learning on a basis of real Auger very inclined showers (positive markers) and real standard showers especially triggered by Time over Threshold (negative marker)), b) to recognize "young" showers (on the basis of simulated "young" events (positive markers) and standard Auger events as a negative reference). A three-layer neural network being taught with real very inclined Auger showers shows a good efficiency in pattern recognition of 16-point traces with profiles characteristic for "old" showers. Nevertheless, preliminary simulations of showers with CORSIKA and the response of the water Cherenkov tanks with OffLine suggest that for muonic showers starting a development deeply in the atmosphere ADC traces are not too long and 16-point analysis should be sufficient for a recognition of "young" showers.
The surface detector array of the Pierre Auger Observatory is sensitive to ultra-high energy neutrinos in the cosmic radiation. Neutrinos can interact in the atmosphere close to ground (down-going) ...and, for tau neutrinos, through the Earth-skimming mechanism (up-going) where a tau lepton is produced in the Earth crust that can emerge and decay in the atmosphere. Both types of neutrino-induced events produce an inclined particle air shower that can be identified by the presence of a broad time structure of signals in the water-Cherenkov detectors. We discuss the neutrino identification criteria used and present the corresponding limits on the diffuse and point-like source fluxes.
Provider: - Institution: - Data provided by Europeana Collections- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain ...Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Provider: - Institution: - Data provided by Europeana Collections- Karlsruhe, Karlsruher Institut für Technologie (KIT), Diss., 2016- All metadata published by Europeana are available free of ...restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
The present status of the Pierre Auger Observatory and its recent results on Ultra High Energy Cosmic Rays are shortly reported. The following topics are discussed: (i) the energy spectrum above ~4 = ...10.18 eV, (ii) the arrival directions, (iii) the depth of the shower maximum, (iv) the upper limit on the primary photon flux, (v) the upper limit on the diffuse neutrino flux.
The discovery of extensive air showers by Rossi, Schmeiser, Bothe, Kolhörster and Auger at the end of the 1930s, facilitated by the coincidence technique of Bothe and Rossi, led to fundamental ...contributions in the field of cosmic ray physics and laid the foundation for high-energy particle physics. Soon after World War II a cosmic ray group at MIT in the USA pioneered detailed investigations of air shower phenomena and their experimental skill laid the foundation for many of the methods and much of the instrumentation used today. Soon interests focused to the highest energies requiring much larger detectors to be operated. The first detection of air fluorescence light by Japanese and US groups in the early 1970s marked an important experimental breakthrough towards this end as it allowed huge volumes of atmosphere to be monitored by optical telescopes. Radio observations of air showers, pioneered in the 1960s, are presently experiencing a renaissance and may revolutionise the field again. In the last 7 decades the research has seen many ups but also a few downs. However, the example of the Cygnus X-3 story demonstrated that even non-confirmable observations can have a huge impact by boosting new instrumentation to make discoveries and shape an entire scientific community.
Provider: - Institution: - Data provided by Europeana Collections- Karlsruhe, Karlsruher Institut für Technologie (KIT), Diss., 2014- All metadata published by Europeana are available free of ...restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
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