Scientists from the international collaboration of the Borexino project analyzed the data captured by the geoneutrino detector. This made it possible to determine the amount of radioactive elements in the Earth's mantle. The corresponding article was published in the journal Physical Review D.
The intense magnetic field of the Earth, incessant volcanic activity, the movement of tectonic plates, convection processes in the mantle - all these phenomena are associated with the heating of the Earth's interior. Their nature has been discussed by scientists for the past 200 years. Radioactive elements are considered to be one of the factors affecting the total heat flux created by the core and mantle of our planet. Measurement of the geoneutrino flux can help to understand what contribution they make.
Geoneutrinos are formed as a result of the decay of uranium and thorium in the earth's crust. Every second, a stream of several million geoneutrinos penetrates every square centimeter of the earth's surface. But it is extremely difficult to catch them, because they very weakly interact with matter. They can be observed stably only at two installations in the world, one of which is the Borexino detector.
Scientists have started collecting data from this detector since 2007, and by now they have managed to significantly increase the accuracy of registering the full flow of geoneutrinos. According to scientists, with a probability of 99%, radioactive elements are present not only in the crust of the Earth, but also in its mantle. In the course of the work, researchers, including Russian specialists from the NRC "Kurchatov Institute", Moscow State University named after M. V. Lomonosov and JINR - also for the first time calculated the minimum concentrations of thorium and uranium in the mantle.
Scientists also found that with a probability of 85%, the energy released by these radioactive elements constitutes a significant part of the heat flux that moves from the core and mantle. Thus, the radioactivity of the Earth makes a significant contribution to the energy that feeds volcanic activity, earthquakes, as well as the geodynamo mechanism responsible for the Earth's magnetic field.
In addition, thanks to the study carried out, it was possible to improve the registration of geoneutrinos. This will make it possible in the future to detect more such particles and to study the processes taking place in the bowels of the Earth in more detail.