Status of the BOREXINO solar neutrino experiment

Aim of BOREXINO is to measure in real time solar neutrinos with an energy threshold of about 250 keV via pure leptonic neutrino electron scattering ν + e → ν + e. Special interest in BOREXINO is the first determination of the low energy ⁷Be solar neutrino flux. In the MSW-scenario a strong depletion of this flux should be found. In case of vacuum oscillations a clear time fluctuation in the measured flux is to be expected. In addition the large mixing angle MSW solution can be probed independently by measuring the ν̄_e flux of european power reactors in a long baseline oscillation experiment.