OPERA experiment

"OPERA" redirects here. For other uses, see Opera (disambiguation).

The Oscillation Project with Emulsion-tRacking Apparatus (OPERA) is a scientific instrument for detecting tau neutrinos from muon neutrino oscillations. The experiment is a collaboration between CERN in Geneva, Switzerland, and the Laboratori Nazionali del Gran Sasso (LNGS) in Gran Sasso, Italy. It exploits CERN Neutrinos to Gran Sasso (CNGS). On 31 May 2010, OPERA researchers observed the first tau neutrino candidate event in a muon neutrino beam.^[1] In September 2011, OPERA researchers observed muon neutrinos traveling apparently at faster than lightspeed (see: OPERA neutrino anomaly).

Detector

OPERA, in Hall C of the Gran Sasso underground labs, was built in the timeframe 2003-2008. The taus resulting from the interaction of tau neutrinos will be observed in "bricks" of photographic films (nuclear emulsion) interleaved with lead sheets. Each brick weights roughly 8.3 kg and the two OPERA supermodules contain about 150,000 bricks arranged into parallel walls interleaved with plastic scintillator counters. Each supermodule is followed by a magnetic spectrometer for momentum and charge identification of penetrating particles. During data collection, a neutrino interaction and its corresponding brick are tagged in real time by the scintillators and spectrometers. 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.^[2]

References

1. ^ N. Agafonova et al. (OPERA Collaboration) (2010). "Observation of a first ν_τ candidate event in the OPERA experiment in the CNGS beam". Physics Letters B 691 (3): 138–145. arXiv:1006.1623. Bibcode 2010PhLB..691..138A. doi:10.1016/j.physletb.2010.06.022. 
2. ^ "Opera – The Opera Detector". http://operaweb.lngs.infn.it/spip.php?rubrique39. Retrieved 25 Sep 2011. 

External links

• Opera Main Page
• CERN: First Appearance Of Tau Neutrino
• The appearance of the tau-neutrino
• OPERA publications

Coordinates: 42°28′N 13°34′E / 42.46°N 13.57°E / 42.46; 13.57