[en] The Borexino experiment is taking data since 2007 at the Laboratori Nazionali del Gran Sasso in Italy accomplishing outstanding achievements in the field of neutrino physics. Its success is strongly based on the unprecedented ultra-high radio-purity of the inner scintillator core. The main features of the detector and the impressive results for solar and geo-neutrinos obtained by Borexino so far are summarized. The main focus is laid on the most recent results, i.e. the first real-time measurement of the solar pp neutrino flux and the detection of the signal induced by geo-neutrinos with a significance as high as 5.9 σ. The measurement of the pp neutrino flux represents a direct probe of the major mechanism of energy production in the Sun and its observation at a significance of 10 σ proves the stability of the Sun over a time of at least 10⁵ years. It further puts Borexino in the unique position of being capable to test the MSW-LMA paradigm across the whole solar energy range. The geo-neutrino data allow to infer information concerning important geophysical properties of the Earth that are also discussed. The perspectives of the final stage of the Borexino solar neutrino program that are centered on the goal of measuring the CNO neutrinos that so far escaped any observation are outlined. (authors)

[en] The third phase of the Borexino experiment that's referred to as SOX is devoted to test the hypothesis of the existence of one (or more) sterile neutrinos at a short baseline (∼ 5-10 m). The experimental measurement will be made with artificial sources namely with a ¹⁴⁴Ce-¹⁴⁴Pr antineutrino source at the first stage (CeSOX) and possibly with a ⁵¹Cr neutrino source at the second one. The fixed ¹⁴⁴Ce-¹⁴⁴Pr sample will be placed beneath the detector in a special pit and the initial activity will be about 100-150 kCi. The start of data taking is scheduled for April 2018. The article gives a short description of the preparation for the first stage and shows the expected sensitivity. (authors)