The San Onofre Reactor Neutrino Experiment a Low Energy Test of the Atmospheric Neutrino Anomaly

The long-standing solar neutrino deecit and the anomaly in the ratio of electron to muon neutrinos, found for neutrinos generated in the atmosphere, are intriguing hints at the existence of nite neutrino masses and avor mixing. Our collaboration is preparing a low energy long baseline-oscillation experiment, to test the latter phenomenon. A 12 ton segmented, Gd loaded liquid scintillation detector will be installed at 740 m distance from the San Onofre nuclear power station in California, in an underground vault. The projected sensitivity of m 2 > 10 ?3 eV 2 and sin 2 22 > 0:1 covers the allowed parameter range for the e $ solution of the atmospheric neutrino deecit.