Publications (9)0 Total impact
Article: Antennas for the Detection of Radio Emission Pulses from Cosmic-Ray induced Air Showers at the Pierre Auger Observatory[show abstract] [hide abstract]
ABSTRACT: The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal.09/2012;
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ABSTRACT: The Pierre Auger Observatory is a facility built to detect air showers produced by cosmic rays above 10^17 eV. During clear nights with a low illuminated moon fraction, the UV fluorescence light produced by air showers is recorded by optical telescopes at the Observatory. To correct the observations for variations in atmospheric conditions, atmospheric monitoring is performed at regular intervals ranging from several minutes (for cloud identification) to several hours (for aerosol conditions) to several days (for vertical profiles of temperature, pressure, and humidity). In 2009, the monitoring program was upgraded to allow for additional targeted measurements of atmospheric conditions shortly after the detection of air showers of special interest, e.g., showers produced by very high-energy cosmic rays or showers with atypical longitudinal profiles. The former events are of particular importance for the determination of the energy scale of the Observatory, and the latter are characteristic of unusual air shower physics or exotic primary particle types. The purpose of targeted (or "rapid") monitoring is to improve the resolution of the atmospheric measurements for such events. In this paper, we report on the implementation of the rapid monitoring program and its current status. The rapid monitoring data have been analyzed and applied to the reconstruction of air showers of high interest, and indicate that the air fluorescence measurements affected by clouds and aerosols are effectively corrected using measurements from the regular atmospheric monitoring program. We find that the rapid monitoring program has potential for supporting dedicated physics analyses beyond the standard event reconstruction.08/2012;
Article: A search for ultra-high energy neutrinos in highly inclined events at the Pierre Auger Observatory[show abstract] [hide abstract]
ABSTRACT: The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavours above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an E^-2 differential energy spectrum the limit on the single flavour neutrino is (E^2 * dN/dE) < 1.74x10^-7 GeV cm^-2 s^-1 sr^-1 at 90% C.L. in the energy range 1x10^17 eV < E < 1x10^20 eV.02/2012;
Article: Description of Atmospheric Conditions at the Pierre Auger Observatory using the Global Data Assimilation System (GDAS)[show abstract] [hide abstract]
ABSTRACT: Atmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malarg\"ue and averaged monthly models, the utility of the GDAS data is shown.01/2012;
Article: Search for Point-like Sources of Ultra-high Energy Neutrinos at the Pierre Auger Observatory and Improved Limit on the Diffuse Flux of Tau Neutrinos[show abstract] [hide abstract]
ABSTRACT: The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy E ν between 10 17 eV and 10 20 eV from point-like sources across the sky south of +55° and north of –65° declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth's crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of ~3.5 years of a full surface detector array for the Earth-skimming channel and ~2 years for the downward-going channel. An improved upper limit on the diffuse flux of tau neutrinos has been derived. Upper limits on the neutrino flux from point-like sources have been derived as a function of the source declination. Assuming a differential neutrino flux k PS · E –2 ν from a point-like source, 90% confidence level upper limits for k PS at the level of ##IMG## [http://ej.iop.org/icons/Entities/ap.gif] ≈ 5 × 10 –7 and 2.5 × 10 –6 GeV cm –2 s –1 have been obtained over a broad range of declinations from the searches for Earth-skimming and downward-going neutrinos, respectively.The Astrophysical Journal Letters. 01/2012; 755(1):L4.
Article: ABOUT THE POSSIBILITY TO MEASURE SOME STANDARD MODEL PARAMETERS AND SEARCH FOR NEW PHYSICS WITH LOW ENERGY NEUTRINOS*[show abstract] [hide abstract]
ABSTRACT: There are fundamental questions in particle and astroparticle physics that are still open. New experimental facilities as sources of particles and detection systems are needed to solve them. An incompletely understood sector of particle physics is the low energy neutrino interactions. The scope of this contribution is to investigate the possibility to measure some Standard Model parameters and search for new physics with low energy neutrinos and to suggest the possibility to obtain neutrinos with well determined energies. This physics and some experimental aspects could be applied in the next generation of underground detectors with very large volume, in particular in the LAGUNA project. Arguments of interest for some physics aspects and measurable quantities using neutrinos with low energy are presented. Some possibilities to obtain intense neutrino beams with controlled energy are subsequently discussed.Romanian Reports on Physics 01/2012; 64(1):24-32.
Article: The LAGUNA design study-towards giant liquid based underground detectors for neutrino physics and astrophysics and proton decay searches[show abstract] [hide abstract]
ABSTRACT: d) Horia Hulubei National Institute of RD for Physics and Nuclear Engineering, IFIN-HH, 407 Atomistilor Street, R-077125, Magurele, jud. ILFOV, PO Box MG-6, postal code RO-077125, Romania (e) ETH Zurich, 101 Raemistrasse, CH-8092 Zurich (f) The University of Sheffield (USFD), New Spring House 231, Glossop Road, Sheffield S102GW, United Kingdom (g) Lombardi Engineering Limited, via R.Simen, CH-6648, Minusio (h) Commissariat à l'Energie Atomique (CEA)/ Direction des Sciences de la Matière, 25 rue Leblanc, Paris 75015, France (i) Laboratorio Subterraneo de Canfranc (LSC), Plaza del Ayuntamiento no. 1, 22880 Canfranc (Huesca), Spain (j) Mineral and Energy Economy Research Institute of the Polish Academy of Sciences (IGSMIE-PAN), Wybickiego 7, 30-950 Krakow, Poland (k) Wroclaw University of Technology (PWr Wroclaw), ul. Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland (l) University of Bucarest (UoB), Faculty of Physics Bld.Atomistilor nr.405, Physics Platform, Magurele, Ilfov County, RO-077125, MG-11 Bucharest-Magurele, Romania (m) University of Oulu (U-OULU), 1 Pentti Kaiteran Katu, Oulu 90014, Finland (n) Technische Universität München (TUM), 21 Arcisstrasse, München 80333, Germany (o) University of Aarhus (AU), 1 Norde Ringgade, Aarhus C 8000, Denmark (p) AGT Ingegneria Srl, Perugia, 10 A via della Pallotta, Perugia 06126, Italy (q) Technodyne International Ltd., Unit16, Shakespeare Business Centre Hathaway Close, Eastleigh UK SO 50 4SR, United Kingdom (r) Kalliosuunnittelu Oy Rockplan Ltd., 2 Asemamiehenkatu, Helsinki 00520, Finland (s) University of Jyväskylä (JyU), 9 Survontie, Jyväskylä 40014, Finland (t) Cleveland Potash Limited (CPL), Boulby Mine, Loftus, Saltburn Cleveland, TS13 4UZ, UK (u) Institute of Physics, University of Silesia Uniwersytecka 4, 40-007 Katowice, Poland (v) Universidad Autonoma de Madrid (UAM), C/Einstein no. 1; Rectorado, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain (w) Max-Planck-Institute for Nuclear Physics, Heidelberg (x) KGHM CUPRUM Ltd Research and Development Centre, Pl. 1 Maja, 50-136 Wrocaw, Poland (y) IFJ Pan, H.Niewodniczaski Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-342 Krakow, Poland (z) Max-Planck-Institute for Physics, Munich (A) High Energy Physics Department -A. Soltan Institute * Contribution to the Workshop "European Strategy for Future Neutrino Physics", CERN, Oct. 2009, to appear in the Proceedings.01/2010;
Article: The LAGUNA design study- towards giant liquid based underground detectors for neutrino physics and astrophysics and proton decay searches[show abstract] [hide abstract]
ABSTRACT: The feasibility of a next generation neutrino observatory in Europe is being considered within the LAGUNA design study. To accommodate giant neutrino detectors and shield them from cosmic rays, a new very large underground infrastructure is required. Seven potential candidate sites in different parts of Europe and at several distances from CERN are being studied: Boulby (UK), Canfranc (Spain), Fr\'ejus (France/Italy), Pyh\"asalmi (Finland), Polkowice-Sieroszowice (Poland), Slanic (Romania) and Umbria (Italy). The design study aims at the comprehensive and coordinated technical assessment of each site, at a coherent cost estimation, and at a prioritization of the sites within the summer 2010. Comment: 5 pages, contribution to the Workshop "European Strategy for Future Neutrino Physics", CERN, Oct. 200912/2009;
Article: Search for ultrahigh energy neutrinos in highly inclined events at the Pierre Auger Observatory[show abstract] [hide abstract]
ABSTRACT: The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an E-2 differential energy spectrum the limit on the single-flavor neutrino is E2dN/dE<1.74×10-7GeVcm-2s-1sr-1 at 90% C.L. in the energy range 1×1017eV<E<1×1020eV.Phys. Rev. D. 01/1970; 84(12).