Neutrinos produced in the Sun have different energies. Different types of
detectors are sensitive to different energy ranges.
Image courtesy of John Bahcall, Institute of Advanced Studies
The Solar Neutrino Problem
Theories about
fusion inside the solar core
predict the number of neutrinos
that should reach Earth. Experiments on
Earth have been set up to detect solar neutrinos
in order to test these models. Current measurements show less neutrinos than the number predicted.
The first solar neutrino experiment was performed at the
Homestake mine in South Dakota.
A 600-ton chlorine fluid detector was used. It found
a neutrino count about one third of that predicted.
The experiment at Kamioka, Japan, found about half
of the predicted neutrinos. Recent experiments in Russia (SAGE)
and Italy (GALLEX) use Gallium to detect neutrinos and have
found neutrino fluxes up to 70% of the predicted flux.
Scientists are still trying to find out why their actual counts don't match up with the number of neutrinos that are predicted to come from the Sun.
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