Autonomous radiodetection of air showers with the TREND50 antenna array

D. CHARRIER; K. D. DE VRIES; Q. GOU; J. GU; H. HU; Y. HUANG; S. LE COZ; O. MARTINEAU-HUYNH; V. NIESS; T. SAUGRIN; M. TUEROS; X. WU; J. ZHANG; Y. ZHANG

ASTROPARTICLE PHYSICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2019

0927-6505

TREND50 is a radio detection setup of 50 self-triggered antennas working inthe 50-100 MHz frequency range and deployed in a radio-quiet valley of theTianshan mountains (China). TREND50 achieved its goal: the autonomousradiodetection and identification of air showers. Thanks to a dedicated offline selection algorithm, 564 air shower candidates were indeed selected outof 7.010E8 transient radio signals recorded during the 314 live days of datataken during the first two years of operation of this setup (2011 and 2012).This event rate, as well as the distribution of the candidate directions of arrival, is consistent with what is expected from cosmic-ray-induced air showersaccording to simulations, assuming an additional ∼20% contamination of thefinal sample by background events. This result is obtained at the cost of areduced air shower detection efficiency, estimated to be ∼3%. This low efficiency is mostly due to the large amount of dead time of the setup. Thisresult paves the way for the GRANDProto35 experiment, the first stage ofthe GRAND project.