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== Introduction ==

The Kamioka Neutrino Detection Experiment, commonly referred to as KamiokaNDE or Kamiokande, is a pioneering neutrino observatory located in the Kamioka mine, near the town of Hida in Gifu Prefecture, Japan. This experiment has played a significant role in advancing our understanding of neutrinos, subatomic particles that are fundamental to the Standard Model of particle physics. The KamiokaNDE has been instrumental in detecting neutrinos from various sources, including the Sun, supernovae, and cosmic rays.

== History and Development ==

The KamiokaNDE project was initiated in the early 1980s by a team of Japanese physicists led by Masatoshi Koshiba. The primary goal was to detect [[proton decay]], a hypothetical form of radioactive decay predicted by certain grand unified theories (GUTs). The experiment was constructed in the Kamioka mine, which provided a deep underground environment to shield the detector from cosmic ray interference.

The original KamiokaNDE detector, completed in 1983, consisted of a cylindrical tank filled with 3,000 tons of pure water and lined with approximately 1,000 photomultiplier tubes (PMTs). These PMTs were designed to detect the faint flashes of Cherenkov radiation produced when neutrinos interacted with the water.

== Scientific Contributions ==

=== Solar Neutrinos ===

One of the most significant achievements of the KamiokaNDE was the detection of [[solar neutrinos]]. These neutrinos are produced in the core of the Sun during nuclear fusion reactions. The experiment provided crucial data that helped resolve the [[solar neutrino problem]], a long-standing discrepancy between the predicted and observed flux of solar neutrinos. The KamiokaNDE's observations supported the theory of neutrino oscillation, which suggests that neutrinos can change flavors as they travel through space.

=== Supernova Neutrinos ===

The KamiokaNDE gained international recognition in 1987 when it detected neutrinos from [[Supernova 1987A]], a stellar explosion in the Large Magellanic Cloud. This event marked the first time that neutrinos from a supernova were observed, providing valuable insights into the mechanisms of supernova explosions and the properties of neutrinos.

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=== Atmospheric Neutrinos ===

In addition to solar and supernova neutrinos, the KamiokaNDE also detected [[atmospheric neutrinos]], which are produced when cosmic rays interact with the Earth's atmosphere. The data collected by the experiment provided evidence for neutrino oscillation and contributed to the understanding of neutrino mass.

== Technical Details ==

=== Detector Design ===

The KamiokaNDE detector was designed to maximize the detection of Cherenkov radiation. The cylindrical tank, measuring 16.0 meters in diameter and 15.6 meters in height, was filled with ultra-pure water to reduce background noise. The PMTs, each with a diameter of 50 centimeters, were arranged in a grid pattern on the inner surface of the tank to capture the Cherenkov light produced by neutrino interactions.

=== Data Collection and Analysis ===

The data collected by the KamiokaNDE were analyzed using sophisticated algorithms to identify neutrino events and distinguish them from background noise. The experiment employed various calibration techniques to ensure the accuracy and reliability of the data. The analysis of the data required significant computational resources and involved collaboration with international research institutions.

== Legacy and Successors ==

The success of the KamiokaNDE led to the development of its successor, the [[Super-Kamiokande]] (Super-K), which began operations in 1996. The Super-K detector is an upgraded version of the original KamiokaNDE, featuring a larger tank (50,000 tons of water) and more PMTs (over 11,000). The Super-K has continued to make groundbreaking discoveries in neutrino physics, including further evidence for neutrino oscillation and the detection of neutrinos from distant astrophysical sources.

The legacy of the KamiokaNDE also paved the way for other neutrino observatories around the world, such as the [[Sudbury Neutrino Observatory]] (SNO) in Canada and the [[IceCube Neutrino Observatory]] in Antarctica. These experiments have built upon the foundational work of the KamiokaNDE to explore new frontiers in neutrino research.

== See Also ==

* [[Neutrino]]
* [[Cherenkov Radiation]]
* [[Proton Decay]]
* [[Super-Kamiokande]]
* [[Sudbury Neutrino Observatory]]
* [[IceCube Neutrino Observatory]]

[[Category:Neutrino observatories]]
[[Category:Particle physics experiments]]
[[Category:Physics in Japan]]