Abstract
Geoneutrinos are electron neutrinos and antineutrinos emitted in radioactive decays of radionuclides naturally occurring in the Earth. Thanks to experimental advances in fundamental neutrino research, geoneutrinos from 232Th and 238U decay chains have now been independently measured by two experiments, and more measurements are expected in the coming years.
The flux of geoneutrinos at a detector location scales with the inverse of the squared distance to the emitter, and is thus a nontrivial function of the abundance and spatial distribution of the radionuclides in the Earth interior. Geoneutrino measurements provide a particle physics tool to investigate the inaccessible Earth, namely to place limits on the amount of Th and U, therefore radiogenic power available in various domains inside the Earth.
A movable ocean-bottom geoneutrino detector, technology to detect the direction of the incoming geoneutrino, and method to detect geoneutrinos from 40K decay all remain exciting goals in neutrino geoscience.