Solar neutrino and terrestrial antineutrino fluxes measured with Borexino at LNGS

Borexino is a real time liquid scintillator detector for low energy neutrino and antineutrino spectroscopy located at the Gran Sasso National Laboratories (Italy). Thanks to its unique features - extremely low background, large scintillator mass (278 tons), low energy threshold and a carefully designed muon-veto system- it is giving a substantial contribution to key issues in many physics fields, like neutrino properties, solar physics, rare decays, Earth composition and heat balance. During the current year the Borexino collaboration efforts have been addressed to two main goals: the analysis of data set collected until December 2009 and the scintillator re-purification operations. Results obtained in 2010 concern: the update of solar ⁷Be-ν flux day/night asymmetry, the measurement of the solar ⁸B-ν flux with a lower threshold down to 3 MeV, the first observation of the geoneutrino signal at 4.2σ C.L., the measure of the European reactors antineutrino disappearence on a baseline of 1000 km, limits on the transition probability of solar neutrinos to antineutrinos and the most stringent up-to-date experimental bounds on Pauli exclusion principle violating transitions in ¹²C nuclei. Purification campaigns aiming to reduce mainly the ⁸⁵Kr and ²¹⁰Bi contaminants in the scintillator are in progress. The observed reduction of background is already sizeable and it is marking the beginning of a new phase of precision solar neutrino spectroscopy with an increased sensitivity to the more elusive components of solar neutrino flux like pep and CNO neutrinos.