DONUT

DONUT (Direct Observation of the NU Tau, E872) was an experiment at Fermilab dedicated to the search for tau neutrino interactions. Even though the detector operated only during a few months in the summer of 1997, it was largely successful. By detecting the tau neutrino, it confirmed the existence of the last lepton predicted by the Standard Model. The data from the experiment was also used to put an upper limit on the tau neutrino magnetic moment and measure its interaction cross section.

Read more about DONUT:  Principle, Result