Wikipedia
Borexino is a particle physics experiment to study low energy (sub-MeV) solar neutrinos. The name Borexino is the Italian diminutive of BOREX ( Boron solar neutrino experiment, the original experimental proposal with a different scintillator). The experiment is located at the Laboratori Nazionali del Gran Sasso near the town of L'Aquila, Italy, and is supported by an international collaboration with researchers from Italy, the United States, Germany, France, Poland and Russia. The experiment is funded by multiple national agencies including the INFN (National Institute for Nuclear Physics) and the NSF (National Science Foundation).
The detector is a high-purity liquid scintillator calorimeter. It is placed within a stainless steel sphere which holds the signal detectors ( photo-multiplier tubes or PMTs) and is shielded by a water tank to protect it against external radiation and tag incoming cosmic muons that manage to penetrate the overburden of the mountain above. The primary aim of the experiment is to make a precise measurement of the beryllium-7 neutrino flux from the sun and compare it to the Standard solar model predictions. This will allow scientists to further understand the nuclear fusion processes taking place at the core of the Sun and will also help determine properties of neutrino oscillations, including the MSW effect. Other goals of the experiment are to detect boron-8, pp, pep and CNO solar neutrinos as well as anti-neutrinos from the Earth and nuclear power plants. The project may also be able to detect neutrinos from supernovae within our galaxy. Searches for rare processes and potential unknown particles are also underway. The SOX project will study the possible existence of sterile neutrinos or other anomalous effects in neutrino oscillations at short ranges. Borexino is a member of the Supernova Early Warning System.