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Browsing by Author "Pierre Auger collaboration (404 authors)"

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  • Calibration of the logarithmic-periodic dipole antenna (LPDA) radio stations at the Pierre Auger Observatory using an octocopter
    Publication . Pierre Auger collaboration (404 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, Lorenzo; Conceição, Ruben; Diogo, Francisco; Espadanal, João; Lopes, Luis; Pimenta, Mário; Santos, Eva; Sarmento, Raul; Tomé, Bernardo
    An in-situ calibration of a logarithmic periodic dipole antenna with a frequency coverage of 30 MHz to 80 MHz is performed. Such antennas are part of a radio station system used for detection of cosmic ray induced air showers at the Engineering Radio Array of the Pierre Auger Observatory, the so-called Auger Engineering Radio Array (AERA) . The directional and frequency characteristics of the broadband antenna are investigated using a remotely piloted aircraft carrying a small transmitting antenna. The antenna sensitivity is described by the vector effective length relating the measured voltage with the electric-field components perpendicular to the incoming signal direction. The horizontal and meridional components are determined with an overall uncertainty of 7.4(+0.9)(−)(0.3)% and 10.3(+2.8)(−)(1.7)% respectively. The measurement is used to correct a simulated response of the frequency and directional response of the antenna. In addition, the influence of the ground conductivity and permittivity on the antenna response is simulated. Both have a negligible influence given the ground conditions measured at the detector site. The overall uncertainties of the vector effective length components result in an uncertainty of 8.8(+2.1)(−)(1.3)% in the square root of the energy fluence for incoming signal directions with zenith angles smaller than 60°.
    2017-10-16Journal article Open access Show more
  • Spectral Calibration of the Fluorescence Telescopes of the Pierre Auger Observatory
    Publication . Pierre Auger collaboration (404 authors); Abreu, Pedro; Andringa, Sofia; Assis, Pedro; Barreira Luz, Ricardo Jorge; Blanco, Alberto; Cazon, Lorenzo; Conceição, Ruben; Diogo, Francisco; Espadanal, João; Lopes, Luis; Pimenta, Mário; Riehn, Felix; Santos, Eva; Sarmento, Raul; Tomé, Bernardo
    We present a novel method to measure precisely the relative spectral response of the fluorescence telescopes of the Pierre Auger Observatory. We used a portable light source based on a xenon flasher and a monochromator to measure the relative spectral efficiencies of eight telescopes in steps of 5 nm from 280 nm to 440 nm. Each point in a scan had approximately 2 nm FWHM out of the monochromator. Different sets of telescopes in the observatory have different optical components, and the eight telescopes measured represent two each of the four combinations of components represented in the observatory. We made an end-to-end measurement of the response from different combinations of optical components, and the monochromator setup allowed for more precise and complete measurements than our previous multi-wavelength calibrations. We find an overall uncertainty in the calibration of the spectral response of most of the telescopes of 1.5% for all wavelengths; the six oldest telescopes have larger overall uncertainties of about 2.2%. We also report changes in physics measurables due to the change in calibration, which are generally small.
    2017-10Journal article Open access Show more