SEMINAR    Thursday, 28th September 2006 - h. 15:00 Auditorium B. Touschek   A. Paoloni (INFN - LNF) The start-up of the OPERA experiment Abstract The OPERA experiment, located at the Gran Sasso underground laboratory, is devoted to the research of direct evidence for muon neutrino into tau neutrino oscillations in the long baseline muon neutrino beam produced at CERN (CNGS). In order to detect the appearance of tau neutrinos, both emulsions and electronic detectors are needed for vertex location, tau lepton identification and background rejection. During two weeks in august 2006, the CNGS beam and the electronic detectors of OPERA were successfully operated and 300 neutrino events were recorded by the OPERA experiment with almost no down time. The beam and the OPERA detectors are presented as well as the first results of the run.