Borexino is similar to a "matrioska", dipped in 2.400 tons of highly purified water.

Inside it, a steel sphere contains 1000 tons of a hydrocarbon (pseudocumene) and within a smaller nylon sphere are 300 tons of scintillating liquid

In the innermost sphere neutrinos interact with the scintillator liquid and produce small flashes of light. Borexino observes dozens of these signals every day

The photomultipliers, which are ultra-sensitive technological eyes, see and record the light flashes produced by the neutrinos

Thermonuclear fusion in the Sun produces continually enormous quantities of neutrinos reaching the Earth: each second, 60 billions of them pass through a finger's tip

Borexino observes low energy neutrinos (less then 1 Mev) that are produced on the solar core's surface

Nylon sphere,diameter 8,5 m

Stainless steel sphere,diameter13,7 m

2.200photomultipliers

(inwards)

Muons apparatus:200 photomultipliers

(outwards)

300 tonsscintillator

liquid

Thin nylon layer(radon gas barrier)

Shieldingsteel dishes

Stainless steelbox of water,

diameter 18 m

water

ScintillatorScintillator

Hydrocarbon layerHydrocarbon layer(pseudocumene)(pseudocumene)

Scintillator

Hydrocarbon layer(pseudocumene)

Carrier chordsThe Borexino experiment

NEUTRINOS

SUN

1,5 kmof rocks

Borexino

Gran SassoMount

Neutrinos, which are neutral particles with a very small mass, interact very rarely with the other constituents of matter and can pass unhindered through enormous thicknesses of every kind of material

Borexino is an international project with Italian leadership, involving research centres of six different countriesand about 100 experts, between physicists, engineers and technicians.

To detect them, big apparatuses are needed. They are placed underground to shield the signals produced by other particles coming from the Cosmos and the natural radioactivity of the environment

Gran Sasso