Low energy solar neutrinos with borexino

Low energy solar neutrinos are a unique tool to investigate the nuclear reactionsthat fuel the Sun. The Borexino experiment, based on a 270 ton ultra-pure liquid scintillator detector at Laboratori Nazionali del Gran Sasso, was conceivedto measure solar neutrino fluxes in the MeV and sub-MeV energy range. Thedata taking started on 2007 and thanks to the unprecedented level of radiopurity achieved in the inner part of the detector, a real time spectroscopy ofthe main components of the pp chain was possible. After a purification process, in the phase II data, the simultaneous fit of all the pp-chain componentswas performed and the interaction rates of pp, 7Be and pep were extractedwith the highest precision to date. In this paper, after a description of themain properties of Borexino detector, the most important analysis techniques,necessary for the data selection and for the final fit of the phase II data will beexplained.