![]() The Super-Kamiokande Collaboration announced the first evidence of neutrino oscillation in 1998. Super-Kamiokande started operation in 1996. This led to the construction of Super-Kamiokande, with fifteen times the water and ten times as many PMTs as Kamiokande. Higher sensitivity was also necessary to obtain high statistical confidence in its results. ĭespite successes in neutrino astronomy and neutrino astrophysics, Kamiokande did not achieve its primary goal, the detection of proton decay. ![]() In addition, the US has also contributed about 2000 20 cm PMTs recycled from the IMB experiment. The US portion of the proposal, which was primarily to build the OD system, was approved by the US Department of Energy in 1993 for $3 M. The Super-Kamiokande project was approved by the Japanese Ministry of Education, Science, Sports and Culture in 1991 for total funding of approximately $100 M. The ability of the Kamiokande experiment to observe the direction of electrons produced in solar neutrino interactions allowed experimenters to directly demonstrate for the first time that the Sun was a source of neutrinos. As a result, the detector (KamiokaNDE-II) had become sensitive enough to detect neutrinos from SN 1987A, a supernova which was observed in the Large Magellanic Cloud in February 1987, and to observe solar neutrinos in 1988. The detector was upgraded, starting in 1985, to allow it to observe solar neutrinos. The detector, named KamiokaNDE for Kamioka Nucleon Decay Experiment, was a tank 16.0 m (52 ft) in height and 15.6 m (51.2 ft) in width, containing 3,058 metric tons (3,400 US tons) of pure water and about 1,000 photomultiplier tubes (PMTs) attached to its inner surface. ![]() The purpose of the observatory was to detect whether proton decay exists, one of the most fundamental questions of elementary particle physics. History Ĭonstruction of the predecessor of the present Kamioka Observatory, the Institute for Cosmic Ray Research, University of Tokyo began in 1982 and was completed in April 1983. Highly relativistic muons, in contrast, travel almost straight through the detector and produce rings with sharp edges. The multiple scattering of electrons is large, so electromagnetic showers produce fuzzy rings. From the sharpness of the edge of the ring the type of particle can be inferred. Using the timing and charge information recorded by each PMT, the interaction vertex, ring direction and flavor of the incoming neutrino is determined. The Cherenkov light is projected as a ring on the wall of the detector and recorded by the PMTs. This creates a cone of light known as Cherenkov radiation, which is the optical equivalent to a sonic boom. Ī neutrino interaction with the electrons or nuclei of water can produce a charged particle that moves faster than the speed of light in water, which is slower than the speed of light in vacuum. There is a Tyvek and blacksheet barrier attached to the superstructure that optically separates the ID and OD. Mounted on the superstructure are 11,146 photomultiplier tubes (PMT) 50 cm (20 in) in diameter that face the ID and 1,885 20 cm (8 in) PMTs that face the OD. The tank volume is divided by a stainless steel superstructure into an inner detector (ID) region, which is 36.2 m (119 ft) in height and 33.8 m (111 ft) in diameter, and outer detector (OD) which consists of the remaining tank volume. It consists of a cylindrical stainless steel tank that is 41.4 m (136 ft) tall and 39.3 m (129 ft) in diameter holding 50,220 metric tons (55,360 US tons) of ultrapure water. The Super-K is located 1,000 m (3,300 ft) underground in the Mozumi Mine in Hida's Kamioka area. The observatory was designed to detect high-energy neutrinos, to search for proton decay, study solar and atmospheric neutrinos, and keep watch for supernovae in the Milky Way Galaxy. It is located 1,000 m (3,300 ft) underground in the Mozumi Mine in Hida's Kamioka area. Super-Kamiokande (abbreviation of Super-Kamioka Neutrino Detection Experiment, also abbreviated to Super-K or SK Japanese: スーパーカミオカンデ) is a neutrino observatory located under Mount Ikeno near the city of Hida, Gifu Prefecture, Japan.
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