PT Journal
AU Pierre Auger Collaboration (Abraham, Jea
   Pastor, S
TI Trigger and aperture of the surface detector array of the Pierre Auger Observatory
SO Nuclear Instruments & Methods in Physics Research A
JI Nucl. Instrum. Methods Phys. Res. A
PY 2010
BP 29
EP 39
VL 613
IS 1
DI 10.1016/j.nima.2009.11.018
LA English
DE Ultra high energy cosmic rays; Auger Observatory; Extensive air showers; Trigger; Exposure
AB The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above 3 x 10(18) eV, for all zenith angles between 0 degrees and 60 degrees, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance.
ER