Hydrogen Hydrogen

Fusion

Deuterium

FusionFusionFusionFusionFusionFusion

THE SUN AS BOREXINO SEES IT IN REAL TIME

Hydrogen

Deuterium

Water

Hydorcarbonscintillator

(pseudocumene)

Scintillator300 tons

organic liquid scintillator

2.200 photomultiplier tubes(facing inwards)

Vessel retention ropes

Muons detector:200 photomultiplier tubes

(facing outwards)

Stainless steelwater tank

18 m diameter

Gran Sasso

By analyzing P-P neutrino emission,Borexino has shown that the energyproduced today in the Sun’s core is equalto that produced 100.000 years ago.

Gran Sassomountain

1,4 km of rock

Borexino displays arussian doll structure.Surrounded by 2.400tons of highly purifiedwater, a stainless steelsphere contains 1.000tons of a liquidhydrocarbon(pseudocumene).At its center, within a smaller nylon sphere, are 300 tons of scintillating liquid.

The photomultiplier tubes,acting as ultra-sensitive artificial eyes, detect and record the light flashes produced by the neutrinos.

Borexino observes dozens ofthese signals every day.

N

P

P

P

100.000years

LNGSLaboratori Nazionali

del Gran Sasso

Borexino

THE THERMONUCLEAR FUSION REACTION THAT PRODUCESTHE P-P NEUTRINOS RECENTLY STUDIED BY BOREXINO

CORE

RADIATIVEZONE

CONVECTIVE ZONE

INSIDETHE SUN

Stainless steel sphere13,7 m diameter

THE BOREXINO DETECTOR: HOW IT WORKS

Nylon sphere8,5 m diameter

Schieldingsteel dishes

Thin nylon film(radon gas barrier)

PHOTONSThe radiation studied so far ismade up of photons, whichinteract with solar matter.It takes about 100.000years for it to reachthe Sun’s surfaceand reach Earth.

Neutrinos are particles with noelectric charge and a tiny mass.They rarely interact with matterand may cross it undisturbed.That’s why they take 8 minutesto get there from the coreof the Sun to the Earth.

NEUTRINOS

8 minutes

Positron

Neutrinowith maximunenergyof 420keV Within this

innermost sphereneutrinos interact with the liquid scintillatorproducing small flashes of light.