Results of a self-triggered prototype system for radio-detection of
extensive air showers at the Pierre Auger Observatory
ArXiv 1211.0572 (2012)
Authors:
The Pierre Auger Collaboration, S Acounis, D Charrier, T Garçon, C Rivière, P Stassi
Abstract:
We describe the experimental setup and the results of RAuger, a small
radio-antenna array, consisting of three fully autonomous and self-triggered
radio-detection stations, installed close to the center of the Surface Detector
(SD) of the Pierre Auger Observatory in Argentina. The setup has been designed
for the detection of the electric field strength of air showers initiated by
ultra-high energy cosmic rays, without using an auxiliary trigger from another
detection system. Installed in December 2006, RAuger was terminated in May 2010
after 65 registered coincidences with the SD. The sky map in local angular
coordinates (i.e., zenith and azimuth angles) of these events reveals a strong
azimuthal asymmetry which is in agreement with a mechanism dominated by a
geomagnetic emission process. The correlation between the electric field and
the energy of the primary cosmic ray is presented for the first time, in an
energy range covering two orders of magnitude between 0.1 EeV and 10 EeV. It is
demonstrated that this setup is relatively more sensitive to inclined showers,
with respect to the SD. In addition to these results, which underline the
potential of the radio-detection technique, important information about the
general behavior of self-triggering radio-detection systems has been obtained.
In particular, we will discuss radio self-triggering under varying local
electric-field conditions.
