The elusive properties of neutrinos have always been both a blessing and a curse for their employment in the comprehension of the Universe. Their weak interaction with matter makes these particles particularly challenging to detect, but also precious probes for exploring the most remote parts of the Earth, Sun and stars. Starting from the mid-twentieth century geoneutrinos, the electron antineutrinos originating from the β- emitters inside our planet, were proposed as a precious tool for exploring the inner Earth. While decaying, the radioisotopes belonging to 238U and 232Th decay chains release geoneutrinos and energy, dissipated as heat, in a well-fixed ratio. The measurement of the geoneutrino flux at surface thus permits to estimate the uranium and thorium content of our planet’s mantle and in turn to derive its radiogenic heat production.
We present valuable insights on mantle radioactivity and on the contribution of radiogenic heat to the Earth’s energy budget, combining theoretical crustal models and the latest geoneutrino flux measurements provided by KamLAND (Japan) and Borexino (Italy) experiments. The obtained results are discussed and framed in the puzzle of the diverse Earth’s compositional models, analyzing their implications on planetary heat budget and composition. The multi site investigation of the geoneutrino signal permitted to disentangle the mantle contribution, assessing the radiogenic power, and consequently deriving the estimates for the abundances of uranium and thorium in the mantle.
The promising potential of geoneutrinos in investigating deep Earth radioactivity confer them a prestigious role in the comprehension of geodynamical processes of our planet and lets us glimpse a bright future for Earth Sciences in view of the next generation SNO+ (Canada) and JUNO (China) antineutrino experiments.