ABSTRACT
Solar neutrinos has been one of the longest standing and most interesting problems in particle astrophysics. From the astrophysical point of view, solar neutrinos are the only objects besides the study of solar oscillations (helioseismology) which allow us a direct view into the solar interior. Solar neutrinos are labeled according to their production reaction in the fusion network. The first reaction step is the fusion of protons into deuteron (deuterium nucleus). In principle there are two kinds of solar neutrino experiments: radiochemical and real-time experiments. The measured total solar neutrino flux is in accordance with the Standard Solar Model predictions but only about 30 percent of them arrive at Earth as electron neutrinos. Despite the fact that the solar neutrino problem is solved, still great efforts are being made to improve measurements of the solar neutrino spectrum due to its importance to both astrophysics and elementary particle physics.
