Borexino

In the exciting field of the solar neutrino investigation a new player is expected to enter soon this challenging arena: Borexino. Such a massive, calorimetric, liquid scintillation detector, completely installed and ready for operations at the underground Gran Sasso Laboratory, is aimed towards one of the more demanding aspect of this research, i.e. the real time determination of the flux of the sub-MeV neutrinos produced in the 7Be electron capture reaction in the Sun. As a prototype program for the large scale detector, the Counting Test Facility, operated for several years at Gran Sasso, gave the convincing demonstration that the crucial technological challenge of the experiment, the achievement in the scintillator of unprecedented radiopurity levels, can be reached successfully, thus providing the solid experimental foundation for the powerful detection technique with which Borexino will start to reveal solar neutrinos from the middle of 2007.