The OPERA Detector

Schematic view of the Opera Detector

OPERA is located in the Hall C of the Gran Sasso underground labs. its construction started in 2003 and the apparatus has been completed in summer 2008. In OPERA, the tau leptons resulting from the interaction of tau neutrinos will be observed in “bricks” of photographic films (“nuclear emulsion”) interleaved with lead sheets. Each brick has an approximate weight of 8.3 kg and the two OPERA targets contain about 150000 bricks arranged into parallel walls and interleaved with plastic scintillator counters. Each target is followed by a magnetic spectrometer for momentum and charge identification of penetrating particles. During the data taking, a neutrino interaction is tagged in real time by the scintillators and the spectrometers, which also provide the location of the bricks where the neutrino interaction occurred. These bricks are extracted from the walls asynchronously with respect to the beam to allow for film development, scanning and for the topological and kinematic search of tau decays.