Description:Simulation and reconstruction of high energy cosmic ray events at the Pierre Auger Observatory
Abstract:The Pierre Auger Observatory is designed to study the cosmic ray radiation in the ultra high energy regime (1018-1020 eV). The Southern Auger Observatory, located near Malargue (Argentina), has been completed in March 2008 and is taking data regularly.
The proposed Auger activities can be grouped into 2 general categories:
1.) Submission of jobs on the grid concerning the simulation of cosmic rays events and their reconstruction through the detector response. This imply the use of cosmic rays simulation packages, such as CORSIKA, AIRES and CONEX, detector modeling, particle tracking and event reconstruction tools, such as GEANT4 and the Auger Offline Framework.
<br>2.) Creation of suitable databases for grid data management.
<br> Having an appropriate set of simulated air showers is a primary need for every kind of analysis. At the present status, two air shower simulation codes, CORSIKA and AIRES, allow a complete tri-dimensional treatment of the development of the cascade, but the use of these codes requires long CPU times and big storage resources to generate a shower, especially at the highest energies. Other codes, such as CONEX, need shorter CPU times and smaller storage resources, but allow a mono-dimensional simulation of the cascade, which is suitable only for fluorescence detector analysis or for fast hybrid simulations. For this reason the set up of libraries of simulated showers, to be used in the event reconstruction phase, is one of the primary Auger task planned in a grid environment.
A following step, once a shower has been simulated in the atmosphere, is the simulation of the interaction with a detector and the final reconstruction of the event. This phase can be also very CPU and storage expensive (especially if it involves queries to Auger databases or the use of GEANT4 to simulate the detector response), as a large number of simulated and reconstructed showers is required by the need of covering all the available phase space (energy-zenith-mass) with simulated data in order