KamLAND

Coordinates: 36°25′21″N 137°18′55″E / 36.4225°N 137.3153°E / 36.4225; 137.3153 The Kamioka Liquid Scintillator Antineutrino Detector (KamLAND) is an electron antineutrino detector at the Kamioka Observatory, an underground neutrino detection facility near Toyama, Japan. The device is situated in a drift mine shaft in the old KamiokaNDE cavity in the Japanese Alps. The site is surrounded by 53 Japanese commercial nuclear reactors. Nuclear reactors produce electron antineutrinos (${\displaystyle {\bar {\nu }}_{e}}$) during the decay of radioactive fission products in the nuclear fuel. Like the intensity of light from a light bulb or a distant star, the isotropically-emitted ${\displaystyle {\bar {\nu }}_{e}}$ flux decreases at 1/R² per increasing distance R from the reactor. The device is sensitive up to an estimated 25% of antineutrinos from nuclear reactors that exceed the threshold energy of 1.8 megaelectronvolts (MeV) and thus produces a signal in the detector.

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