Laboratori Nazionali del Gran Sasso
|Research type||Particle physics, nuclear physics|
|Director||Lucia Votano; Stefano Ragazzi (since October 2012)|
|Location||L'Aquila, Abruzzo, Italy
|Beyond the Standard Model|
Laboratori Nazionali del Gran Sasso (LNGS) is a particle physics laboratory of the INFN, situated near the Gran Sasso mountain in Italy, between the towns of L'Aquila and Teramo, about 120 km from Rome. In addition to a surface portion of the laboratory, there are extensive underground facilities beneath the mountain.
The mission of the laboratory is to host experiments that require a low background environment in the field of astroparticle physics and nuclear astrophysics and other disciplines that can profit of its characteristics and of its infrastructures. The LNGS is, like the three other European underground astroparticle laboratories, Laboratoire Souterrain de Modane, Laboratorio subterráneo de Canfranc, and Boulby Underground Laboratory, a member of the coordinating group ILIAS.
The laboratory consists of a surface facility, located within the Gran Sasso and the Monti della Laga National Park, and extensive underground facilities located next to the 10 km long Traforo del Gran Sasso freeway tunnel.
The experimental halls are covered by about 1400 m of rock, protecting the experiments from cosmic rays. Providing about 3000 metres of water equivalent (mwe) shielding, it is not the deepest underground laboratory, but the fact that it can be driven to without using mine elevators makes it very popular.
The first large experiments at LNGS ran in 1989; the facilities were later expanded. According to its official website, the Gran Sasso lab was, as of 2006[update], the largest underground particle physics laboratory in the world.
Since late August 2006, CERN has directed a beam of muon neutrinos from the CERN SPS accelerator to the Gran Sasso lab, 730 km away, where they will be detected by the OPERA and ICARUS detectors, in a study of neutrino oscillations that will improve on the results of the Fermilab to MINOS experiment.
In May 2010, Lucia Votano, Director of the Gran Sasso laboratories, announced that "[t]he OPERA experiment has reached its first goal: the detection of a tau neutrino obtained from the transformation of a muon neutrino, which occurred during the journey from Geneva to the Gran Sasso Laboratory." This finding indicates a deficiency in the Standard Model of particle physics, as neutrinos would have to have mass for this change to occur.
An effort to determine the Majorana/Dirac nature of the neutrino, called CUORE (Cryogenic Underground Observatory for Rare Events), is scheduled to begin in 2012. The detector will be shielded with lead recovered from an ancient Roman shipwreck, due to the ancient lead's lower radioactivity than recently minted lead. The artifacts are being given to CUORE from the National Archaeological Museum in Cagliari.
In September 2011, Dario Autiero of the OPERA collaboration presented findings that indicated neutrinos were arriving at OPERA about 60 ns earlier than they would if they were travelling at the speed of light. This Faster-than-light neutrino anomaly was not immediately explained. The results were subsequently investigated and confirmed to be wrong. They were caused by a flawed optic fiber cable in OPERA receiver of the laboratory, resulting in late arrival of the clock signal to which the neutrinos' arrivals were compared.
- Colosimo, Gabriele; Crespi, Mattia; Mazzoni, Augusto; Riguzzi, Federica; Jones, Mark; Missiaen, Dominique (14 April 2012), Determination of the CNGS global geodesy (PDF), p. 6, OPERA public note 132 v3
- Particle Chameleon Caught in the act of Changing, Press Release PR08.10, CERN, 31 May 2010, accessed 1 June 2010.
- Roman ingots to shield particle detector, Nature, 15 April 2010.
- Particles break light-speed limit, Nature, 22 September 2011.
- Adam, T.; et al. (OPERA Collaboration) (2012). "Measurement of the neutrino velocity with the OPERA detector in the CNGS beam". Journal of High Energy Physics 2012: 93. arXiv:1109.4897. Bibcode:2012JHEP...10..093A. doi:10.1007/JHEP10(2012)093.
- Neutrinos sent from CERN to Gran Sasso respect the cosmic speed limit, 8 June 2012.