The Gran Sasso National Laboratory (LNGS) is one of four INFN national laboratories.
It is the largest underground laboratory in the world for experiments in particle physics, particle astrophysics and nuclear astrophysics. It is used as a worldwide facility by scientists, presently 750 in number, from 22 different countries, working at about 15 experiments in their different phases.
It is located between the towns of L'Aquila and Teramo, about 120 km from Rome
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The underground facilities are located on a side of the ten kilometres long freeway tunnel crossing the Gran Sasso Mountain. They consist of three large experimental halls, each about 100 m long, 20 m wide and 18 m high and service tunnels, for a total volume of about 180,000 cubic metres.
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Slide by Takaaki Kajita
Slide by Takaaki Kajita
In June 1998 the Super-Kamiokande collaboration revealed its eagerly anticipated results on neutrino interactions to 400 physicists at the Neutrino ’98 conference in Takayama, Japan. A hearty round of applause marked the end of a memorable presentation by Takaaki Kajita of the University of Tokyo that included this slide. He presented strong evidence that neutrinos behave differently than predicted by the Standard Model of particles: The three known types of neutrinos apparently transform into each other, a phenomenon known as oscillation.
Super-K’s detector, located 1000 meters underground, had collected data on neutrinos produced by a steady stream of cosmic rays hitting the Earth’s atmosphere. The data allowed scientists to distinguish between two types of atmospheric neutrinos: those that produce an electron when interacting with matter (e-like), and those that produce a muon (μ-like). The graph in this slide shows the direction the neutrinos came from (represented by cos theta, on the x-axis); the number of neutrinos observed (points marked with crosses); and the number expected according to the Standard Model (shaded boxes).
In the case of the μ-like neutrinos, the number coming straight down from the sky into the detector agreed well with theoretical prediction. But the number coming up through the ground was much lower than anticipated. These neutrinos, which originated in the atmosphere on the opposite side of the globe, travelled 13,000 kilometers through the Earth before reaching the detector. The long journey gave a significant fraction of them enough time to “disappear”—shedding their μ-like appearance by oscillating into a different type of neutrino. While earlier experiments had pointed to the possibility of neutrino oscillations, the disappearance of μ-like neutrinos in the Super-K experiment provided solid evidence.
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The Borexino Collaboration announced the observation of geo-neutrinos at the underground Gran Sasso National Laboratory of Italian Institute for Nuclear Physics (INFN), Italy. The data reveal, for the first time, a definite anti-neutrino signal with the expected energy spectrum due to radioactive decays of U and Th in the Earth well above background.More above......
The International Borexino Collaboration, with institutions from Italy, US, Germany, Russia, Poland and France, operates a 300-ton liquid-scintillator detector designed to observe and study low-energy solar neutrinos. The low background of the Borexino detector has been key to the detection of geo-neutrinos. Technologies developed by Borexino Collaborators have achieved very low background levels. The central core of the Borexino scintillator is now the lowest background detector available for these observations. The ultra-low background of Borexino was developed to make the first measurements of solar neutrinos below 1 MeV and has now produced this first, firm observation of geo-neutrinos.
Geo-neutrinos are anti-neutrinos produced in radioactive decays of naturally occurring Uranium, Thorium, Potassium, and Rubidium. Decays from these radioactive elements are believed to contribute a significant but unknown fraction of the heat generated inside our planet. The heat generates convective movements in the Earth's mantle that influence volcanic activity and tectonic plate movements inducing seismic activity, and the geo-dynamo that creates the Earth's magnetic field.
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