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Neutrinos from stars

Our sun emits around 2 10+38 neutrinos per second !...
and the earth receives more than 40 billions neutrinos per second and cm2.
This huge raining is undetected by the five senses of the homo sapiens.

Number of neutrinos in the universe

about 330 neutrinos per cm3

Stars lives
about 0.000006 neutrinos per cm3

Explosions of supernovae
about 0.0002 neutrinos per cm3

Energies of the neutrinos

Remember: 1 eV (one electron-volt) = 1.6 10-19 Joules

The Big-Bang neutrinos
the most numerous, are also the less energetic:
0.0004 eV
(they have still a speed of 2000 km/s if their mass is 10 eV/c2).

Neutrinos from the sun
until about 20 MeV depending of their origin.

Neutrinos from nuclear reactors
a mean energy of 4.0 MeV (between 1 MeV and 10 MeV).

Neutrinos from accelerators today
very various: a mean energy from 30 MeV (LSND) to 30 GeV (NOMAD).

Cross section for interactions with nucleons
10-38 cm2 at 1 GeV and increasing with energy.

Some surprising numbers

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Last update: 26/06/1999 :
Didier Verkindt