Borexino is a particle physics experiment located in the Hall C of the Laboratories national of Gran Sasso, in central Italy. Its main goal is the study of the properties of a subatomic elementary particle, called the neutrino. Subatomic particles play a major role as building blocks of the ordinary matter that surround us; protons, neutrons and electrons are the main constituents of the atom. Inside the atomic nucleus, protons and neutrons are kept together by the Strong Nuclear interaction, while inside the atom the nucleus and the electrons are bound by the Electromagnetic interaction. ?