The AMIGA infill detector of the Pierre Auger Observatory: performace and first data

I.C. MARIS; THE PIERRE AUGER COLLABORATION (A. ETCHEGOYEN, RESPONSABLE AMIGA)

Beijing

Conferencia; 32 International Cosmic Ray Conference; 2011

IUPAP

We present a first analysis of cosmic rays observed with the AMIGA infill array of the Pierre Auger Observatory. The spacing of 750m between the surface detectors, half the distance of the regular array, allows us to extend the energy range of interest to energies as low as 3×10^17 eV. The lateral distribution function is presented and the uncertainty of the signal at an optimal distance of 450m, used to obtain an energy estimator, is discussed. The first steps towards the measurement of the energy spectrum are described. The calculation of the array exposure and the strategy for the energycalibration of the infill, obtained from events observed in coincidence with the fluorescence detector, are presented.