Performance study of the muon prototype detector at the Pierre Auger Observatory

Abstract

The evolution of the Cosmic Rays spectrum through the second knee and the ankle, and corresponding predicted changes in composition, are crucial to understand the end of Galactic confinement and the effects of propagation on the lower energy portion of the extragalactic flux. The latter is strongly related to the cosmological distribution of sources and to the composition of the injected spectrum. To study this energy region the Pierre Auger Collaboration has extended the energy range of its observatory in Argentina for high quality data from 0.1 to 3 EeV. The extensions include three additional fluorescence telescopes with a more elevated field of view (HEAT) and a nested surface array with 750 and 433 m spacing respectively and additional muon detection capabilities (AMIGA). The BATATA muon counter hodoscope has been designed as an additional prototype with the objective of estimating the electromagnetic contamination expected in the AMIGA muon counters. The subject of the present work has been to perform an end-to-end simulation of the BATATA device. The information coming from the simulation has been then used to analyze the efficiency of discrimination of particle tracks (electrons/photons vs muons) through the use of neural networks, and to estimate the performance of the reconstruction of the arrival direction of muons with the Kalman-filter method.