Borexino solar neutrinos experiment. Borexino (the small Boron Experiment) is part of the Gran Sasso National Laboratory (LNGS), inside the Gran Sasso mountain, Abruzzo, Italy. The mountain shields the LNGS experiments from outside radiation, allowing particle physicists and astrophysicists to study rare interactions involving neutrinos and other particles. The Borexino experiment uses boron-loaded scintillators to measure the flux of neutrinos from the Sun due to beryllium-7 (Be-7) electron captures.