Researchers of the Earth are not so many ways to look inside our own planet. Kola ultradeep well was drilled to a depth of a little over 12 kilometers, which is negligible compared to the radius of the Earth, which is about 6000 kilometers. Much more data has been received from seismic surveys. Changes in the speed and direction of the waves arising from earthquakes, have revealed the boundaries of zones with different physical properties. It has been found that in the center of the Earth is a solid core radius of about 1200 kilometers, surrounded by a layer of liquid material, a thickness of about 2300 kilometers.
The temperature in the center of the Earth reaches 5000 degrees or higher, but it is closer to the surface decreases, while remaining relatively high places in lithospheric faults. If we talk about temperature and heat, most of the heat our planet receives from the sun, and only a small, thousands of times smaller share directly from the depths of the Earth. But in absolute terms it is of great importance, about 40 terawatt – about two thousand times the power of the largest hydroelectric power plant in the world. For this reason, interest in geothermal energy is very large. But back to the topic.
The fact that we can estimate the heat flux emanating from the bowels of the earth, does not give us information about how this heat is obtained. Most likely, the source of the heat of radioactive origin. Unstable isotopes, which are contained in the rocks can undergo alpha or beta decay, which proceeds with liberation of energy. On the role of the working medium of the natural nuclear reactor can claim 238, thorium-232 and potassium-40. Their half-lives comparable to the age of the Earth, allowing them to warm up the planet throughout its life.
If this is indeed the case, then such a reactor inside the Earth can be detected by the flow of neutrinos, which are produced in the process of radioactive decay. But for this you must first register somehow these elusive particles. Unlike other radiation of neutrinos is able to easily penetrate any obstacles. This happens due to the fact that the particles hardly interact with matter – this is the enormous complexity of their detection.
But on the other hand, the physical inactivity makes them safe for living beings, because every second through us at nearly the speed of neutrinos pass huge amounts without causing any harm. In order to catch neutrinos, physicists build complex detectors, immersing them in greater depth under the water or rocks, to get rid of the background noise, because the neutrino can easily pass even through the entire Earth, it is impossible for other particles or waves.The first such geoneutrino, more precisely, born in the beta decay of electron antineutrinos, have been recorded in 2005 for collaboration KamLAND neutrino detector in Japan.
However, the Japanese nuclear power plants close to give the high neutrino signal, against which neutrino were poorly distinguishable. More chances for successful detection of the detector had geoneutrino collaboration Borexino, located in the Gran Sasso mountain range in central Italy, created with the participation of Russian scientists from the Kurchatov Institute, the Joint Institute for Nuclear Research, St. Petersburg Institute of Nuclear Physics. Konstantinov and INP them. D.V.Skobeltsina Moscow State University. This detector consists of several layers.
The container with the ultrapure water is a steel sphere, the inner side of which are mounted a 2000 photomultipliers recording weak light flashes when interacting with a liquid scintillator neutrinos fly through it. Himself liquid scintillator is in a nylon ball, which in turn is placed in the very sphere of steel. This complicated structure increases the sensitivity of the detector. Accumulated 2015 information from the detector allowed the researchers to separate the signal coming from the crust of the Earth, from antineutrinos coming from the inner regions of our planet. In addition, the signal received by the neutrinos generated by the decay of uranium nuclei by neutrinos, the resulting fission of thorium.
As a georeaktora power estimation, there is still great uncertainty. According to information received, the total thermal power from the fission of uranium, thorium and potassium is from 13 to 61 terawatts. These values are, in general, correspond to the heat flux of the Earth, estimated at 45-49 terawatt. Clarify exactly what is the nature of power reactor is in our deep beneath their feet, help neutrino detectors built projects such as SNO +, or LENA. The fact that nuclear reactions produce neutrinos stream that cannot be hidden, suggests the use of neutrino detectors as one of the ways to control atomic energy, for example, to detect illegal nuclear reactor – if suddenly someone decides to create itself.
However, according to experts, the implementation of such an idea is too complex, and in the decades to staff of the International Atomic Energy Agency will have to use other methods. Scientists have found in the language of the universal code.