Experts from NUST MISIS, together with scientists from the Lebedev Physical Institute and the Scientific Research Institute of Nuclear Physics, Moscow State University, prepared for practical application the method of muon radiography, which makes it possible to "see through" objects of a kilometer size. The method is based on the registration of muons - elementary particles produced due to the collision of cosmic rays with the Earth's atmosphere.
Getting into the dense layer of the atmosphere (starting from 40 km and below), protons collide with the molecules that make up our atmosphere. When colliding, different particles are born, some of which quickly turn into muons. They also "perish", having time, however, during their lifetime to pass the entire atmosphere of the Earth (10 thousand muons fly to every square meter of the Earth's surface every minute) and even penetrate 8.5 kilometers under water or 2 kilometers into the earth. The denser the substance, the faster the muon flux weakens. Therefore, if you put a solid object between the "space" and the detector, then the silhouette of this object will eventually appear on the detector. If there are cavities in the object, they will also become visible, since muons flying through them overcome a smaller layer of solid. Three detectors located on opposite sides of the object are usually sufficient,to make a 3D map of it.
The muons are fixed using a series of silver bromide photographic plates. Some of them are illuminated. Then the plates are developed and compared to the exposed areas, building the exposure trajectory. The smaller the bromide grains and the more accurate the matching algorithm, the more correct the picture of the object is.
Muon trace on a photographic plate / NUST; MISIS
Scientists from NUST MISIS, LPI and SINP MSU under the guidance of NUST MISIS leading expert, Doctor of Physical and Mathematical Sciences, Professor Natalia Polukhina have developed track detectors for muon radiography, which allow not only to see muons falling on them, but also to determine with high precision direction of their movement. “By deciphering the readings of the detectors, it is possible to compile a three-dimensional picture of a variety of objects, starting with the meter size of voids in the soil, the distribution of rock density and ending with a map of caves in the mountain,” stressed Alevtina Chernikova, Rector of NUST MISIS.
Tunnel microscope for the analysis of muon tracks / NUST; MISIS
The new technology has other uses as well
Promotional video:
“It is possible to non-invasively assess the state of a volcano vent, a nuclear power plant reactor or a glacier in the mountains,” says Professor Natalya Polukhina. “You can find a new natural underground storage facility for natural gas, catch a fire that starts in a mountain waste from coal mining long before it burns out from the inside, predict a volcanic eruption, or prevent the catastrophic consequences of sinkholes in mines or on city streets. Catastrophic sinkholes in the city of Berezniki, Perm Territory, have already become a huge social problem. And we must remember that residents of many large settlements suffer from such technogenic failures."
Russian experiments, which confirmed the performance of the track method, took place in the mine of the Geophysical Service of the Russian Academy of Sciences in Obninsk: scientists were able to "see" with the help of detectors the structure of the underground structure in which the experiment was carried out. Now a complex of such detectors is being prepared on the basis of a photographic emulsion produced at the domestic enterprise "AVK Slavich", which can be used, for example, to search for hydrocarbons.
NUST MISIS Leading Expert, Doctor of Physics and Mathematics, Professor Natalya Polukhina / NUST MISIS
“Our emulsion track detectors are good because they are easy to operate, do not require electricity to operate, in the case of geological exploration they can do with a much smaller number of wells, and at the same time they are able to distinguish objects ranging in size from a meter to kilometers with high accuracy,” explained Professor Polukhina.
NUST MISIS specialists are working on software that will improve the quality of track decoding, as well as to protect sensors from aggressive media in wells.
