文摘
We present a measurement of the geo-neutrino signal obtained from 1353 days of data with the Borexino detector at Laboratori Nazionali del Gran Sasso in Italy. With a fiducial exposure of proton ¡Á year after all selection cuts and background subtraction, we detected geo-neutrino events assuming a fixed chondritic mass Th/U ratio of 3.9. This corresponds to a geo-neutrino signal with just a probability for a null geo-neutrino measurement. With U and Th left as free parameters in the fit, the relative signals are and . Borexino data alone are compatible with a mantle geo-neutrino signal of , while a combined analysis with the KamLAND data allows to extract a mantle signal of . Our measurement of reactor anti-neutrino events is in agreement with expectations in the presence of neutrino oscillations.