PAVEL CHERENKOV

Pavel Cherenkov was born July 28, 1904 in the village of New Chigla Voronezh region in a peasant family. After high school Paul entered the Voronezh State University, graduating in 1928. Then Cherenkov went first to the preparatory and then in 1932 at the main branch of Physics (Physics and Mathematics then) Institute of the Academy of Sciences.

In 1930 Cherenkov Putintseva married Mary, daughter of a professor of Russian literature. They had two children.

The beginning of scientific activities related to Cherenkov 1932, when he led SI Vavilov began to study the luminescence of solutions uranilovyh salts under the action of gamma-rays.

At first, in full accordance with the law of the Vavilov-Cherenkov radiation in Stokes huge gamma-ray photons of the radiation source have been transformed into small visible light, ie luminescence.

"It is interesting - he reasoned - as it will change if the concentration increase? And if, conversely, dilute solution of water? Is important, of course, not the overall picture, and unambiguous physical law. "

For the time being there are no surprises: less dissolved salt - less luminescence.

Then tells VR Kohler:

"Finally, in the solution are only traces of uranium. Now there is, of course, no luminescence can not be.

But what is? Cherenkov not believe his eyes. Uranyl remained homeopathic dose, but the glow continues. However, very weak, but continues. Why?

Cherenkov pours the liquid, thoroughly washed container and pours it in distilled water. And what is this? Clean water is lit as well as a weak solution. But so far all were convinced that distilled water is unable to luminescence.

Vavilov advises graduate student trying to put together a glass jar of a different material. Cherenkov takes a platinum crucible and poured into it clean water. Under the bottom of the vessel is placed ampoule with four hundred milligrams of radium. Gamma rays escape from the tiny openings and capsules by punching the bottom platinum and a layer of liquid fall into the lens device, aimed down at the contents of the crucible.

Again, adapting to the darkness again, surveillance, and . . . again strange glow.

- This is not luminescence - firmly said Sergei Ivanovich. - This is something else. Some new, unknown until the science of optical phenomena.

Soon all becomes clear that in experiments there are two Cherenkov glow. One of them - luminescence. It is, however, observed only in concentrated solutions. In distilled water under the influence of gamma-irradiation flicker caused by other reason . . .

And behave like other liquids? Maybe it is not in the water?

Postgraduate fills the crucible turns various alcohols, toluene and other substances. All he feels sixteen pure liquids. And weak luminescence is always observed. The astonishing thing! It is very similar in intensity for all materials. Carbon tetrachloride is lit all the stronger izobutanovy alcohol - all weaker, but the difference of the glow does not exceed 25 percent.

Cherenkov trying to extinguish the glow special substances, is strong absorbers ordinary luminescence.

Photo — «Pavel Cherenkov»

It adds to the liquid silver nitrate, potassium iodide, aniline . . . Effect (Extinguishing) no: the glow continues. What?

On the advice of the head, he heats the liquid. On the luminescence is always influenced strongly: it weakens and even stopped altogether. But in this case, the brightness did not change. It turns out there really any special, hitherto unknown phenomenon? What is it? "

In 1934 the "Report of the Academy of Sciences of the USSR" appear first two messages about a new form of radiation: Cherenkov, setting forth in detail the results of experiments, and Vavilov, who is trying to explain them.

Mysterious glow can be seen only within a narrow cone whose axis coincides with the direction of gamma radiation. Taking into account this circumstance, the young scientist put your device in a strong magnetic field. And then he saw that field deflects the narrow cone of emission in the direction. But this is only possible for the electrically charged particles such as electrons. To finally see this, use another type of Cherenkov radiation - beta rays, represent a stream of fast electrons. He irradiated them the same liquid as before, and received the same light effect as if the gamma-irradiation.

It was found that the mysterious optical phenomenon occurs only where there is a movement of fast electrons.

Explanation of the mechanism of transformation of electron motion in the motion of photons unusual glow gave in 1937, the Soviet physicists Igor Tamm and Frank. Electrons fly faster than the light in this environment, and the result is a strange phenomenon: electromagnetic waves generated by electrons lag behind their parents′ and cause the glow.

Soon came the winged phrase: "The Greeks heard the voices of stars, but in the glow of Cherenkov voices of electrons. This singing electrons.

In 1935 Cherenkov postgraduate master′s thesis, and then was promoted to senior researcher Physics Institute. Lebedev, USSR Academy of Sciences (FIAN).

He continued to investigate the discovery of luminescence. In 1936 he established the characteristic property of a new type of radiation - a kind of spatial asymmetry (Cherenkov cone).

After the appearance of the quantitative theory of the phenomenon, developed by Tamm and Frank, Cherenkov in a series of delicate experiments confirms that it is in every detail. Fundamental work on the study of Cerenkov radiation of the open-charged particles moving faster than light, were a significant contribution to world science and recognized classic.

"In addition to fundamental scientific importance, Cerenkov radiation, and have great practical value - wrote IM Dunsky. - Extremely important is its role in high energy physics. When moving fast particles in the medium, a directed light flash, which is recorded by a photomultiplier. These counters are used for the detection of fast charged particles and to determine their properties: direction, the magnitude of the charge, velocity, and t E Cherenkov counters, due to the characteristic features of radiation, significantly extend the experiment and allow to perform experiments that are impossible using conventional fluorescent counters.

Photo — «Pavel Cherenkov»

In particular, Cherenkov radiation was used in the experiments for the detection of the antiproton. It also allows you to watch the fastest particles of cosmic rays. "

For his work in the discovery and study of this phenomenon, together with Vavilov Cherenkov, Tamm and Frank initially in 1946 awarded the State Prize and in 1958 (after the death of Vavilov) Cherenkov, Tamm and Frank have been awarded with the Nobel Prize for physics.

In the postwar years Cherenkov some time engaged in the research of cosmic rays, and also took a leading part in the design and construction of accelerators of light particles. So, in January 1948 under his leadership, launched the first in the USSR betatron. Simultaneously Cherenkov participates in the design and construction of the synchrotron LPI 250 MeV, for which in 1951 received the State Prize. Shortly after the launch of the synchrotron scientists to take leadership over all the work on its improvement, which allowed work to expand the study of electromagnetic interactions in high-energy photons. In the laboratory headed by Cherenkov photomeson processes succeeded in winning a number of interesting results on the study of processes of photodisintegration of helium, photoproduction of pi-mesons, some of the photodisintegration of light nuclei by the method of induced activity.

In the mid-fifties, Cherenkov, together with the IV Chuvilo experimentally investigated the photofission of nuclei of heavy elements. Then, under the leadership of Pavel Alekseevich has successfully developed a new method of accumulation and to obtain colliding electron-positron beams. In 1963-1965 conducted a detailed study of this method, but in early 1966, its principal possibility was tested experimentally on a 280 MeV synchrotron of LPI. Thus, the first time in the practice of physical experiment were obtained colliding beams of electrons and positrons.

"Works on savings and colliding beams in accelerators are of paramount importance for high energy physics - Notes IM Dunsky. - Using this method allows you to transfer existing accelerators in the accumulation mode and thus on the basis of existing experimental facilities to move to research interactions in the field of high and ultrahigh energies. This method was subsequently used to obtain colliding beams at the largest electron accelerator in Cambridge (USA).

In 1964 Pavel Alekseevich elected a corresponding member of the Academy of Sciences of the USSR, and in 1970 - Member of the Academy of Sciences of the USSR.

In 1977, a series of papers on the study of splitting of light nuclei of gamma-ray photons of high energy by cloud chambers operating in high-power electron beam accelerators, Cherenkov was awarded the State Prize of the USSR.

In addition to research activities conducted Cherenkov active in teaching, first in 1948 as professor of the Moscow Energy Institute, and since 1951 and the Moscow Engineering Physics Institute. He gave a start in life a large number of researchers.