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

AUGER COLLABORATION (VER F. SANCHEZ EN PUBL. ADJUNTA)

Beijing

Conferencia; 32th International Cosmic Ray Conference; 2011

IHEP

We present a first analysis of cosmic rays observed with the AMIGA infill array of the Pierre Auger Observa- tory. The spacing of 750 m 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 optimum distance of 450 m, 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 energy calibration of the infill, obtained from events observed in coincidence with the fluorescence detector, are presented.