Résumé
Since its launch on June 11, 2008 the Large Area Telescope (LAT) [1] on-board the Fermi Gamma-ray Telescope‡ has been exploring the gamma-ray sky at energies from 20 MeV to over 300 GeV. Five years of nearly flawless operations allowed a constant improvement of the detector knowledge and, as a consequence, continuous update of the events selection and the corresponding instrument response parametrization. The final product of this effort is a comprehensive revision of the entire event-level analysis, from the event reconstruction algorithms in each subsystems to the background rejection technique. The potential improvements include a larger acceptance coupled with a significant reduction in background contamination, better angular and energy resolution and an extension of the energy reach below ~100 MeV and in the TeV range. In this paper I will describe the new reconstruction, the event-level analysis, and show the expected instrument performance with emphasis on the low-energy regime (< 100 MeV).