Borexino, the important international research program that took place in the underground laboratories of Gran Sasso, was successfully completed, marking a step forward in scientific knowledge on sun functioning.

Started in 2007, the experiment was based on the observation of low-energy solar neutrinos, the particles produced by nuclear reactions taking place inside the sun.

Unlike other particles (photons), which take millions of years to reach the surface of the sun, neutrinos reach the earth after only eight minutes from their generation. For this reason they represent the most direct means for knowing the processes occurring inside of the sun.

Borexino confirmed the two main star fusion reactions and the detection of neutrinos produced in the proton-proton nuclear reaction that produces 99% of the sun’s energy. Also, the first observation of neutrinos from the cycle occurred.

The radiopurity of Borexino’s experimental apparatus ensured the full success of the experiment.

Walter Tosto SpA has contributed to the project since 1998 through the construction of a Pure stainless steel spherical tank with a diameter of 18 meters, used as a solar shield, as well as a large sphere of 14 meters in diameter, containing 1250 tons of the most radiopure scintillator in the world, in which 2200 photomultipliers dedicated to “observe” the behaviour of neutrinos are installed.

Borexino was one of the first research projects we participated in, a large and complex structure installed over 1 kilometer underground. We are proud to have provided our contribution over the years for the project and very grateful to all the international scientific community for always considering us at their level” said Massimiliano Tacconelli, Nuclear & Big Science Program Manager of Walter Tosto SpA.