KamLAND

KamLAND, or Kamioka Liquid-scintillator Antineutrino Detector, is a neutrino observatory located in the Kamioka mine in Gifu Prefecture, Japan. It is operated by the Kamioka Observatory of the University of Tokyo's Institute for Cosmic Ray Research. The detector uses a large volume of liquid scintillator to detect electron antineutrinos via inverse beta decay, with light produced in the scintillator collected by thousands of photomultiplier tubes and surrounded by shielding to reduce background.

The experiment began data-taking in the early 2000s and achieved its landmark results in 2005, providing the first strong evidence for neutrino oscillations using reactor antineutrinos. The measurements constrained the solar neutrino oscillation parameters, notably theta12 and Delta m^2_21, and established the disappearance of reactor antineutrinos over long baselines.

KamLAND has also detected geoneutrinos, antineutrinos produced by radioactive decays inside the Earth, contributing to understanding of the planet’s radiogenic heat. In addition, KamLAND serves as the host for KamLAND-Zen, a program that loads xenon-136 into the liquid scintillator to search for neutrinoless double beta decay, placing limits on the Majorana nature of neutrinos.

The KamLAND collaboration includes researchers from institutions in Japan, the United States, Europe, and elsewhere. The facility remains an important site for low-background neutrino measurements and for experiments that build on KamLAND’s detector technology.