Frank, Ilya Mikhailovich

October 23, 1908, Mr.. - June 22, 1990
Russian physicist Ilya Mikhailovich Frank was born in St. Petersburg. He was the youngest son of Michael Ludwigovich Frank, professor of mathematics, and Elizabeth Mikhailovna Frank. (Gratsianovoy), by profession a physicist. In 1930. He graduated from Moscow State University, majoring in 'physics', where his teacher was SI. Vavilov, later president of the Academy of Sciences of the USSR, under whose guidance the F. conducted experiments on luminescence and its decay in the solution. In the Leningrad State Optical Institute F. studied the photochemical reactions of optical devices in the laboratory AV. Terenina. Here his research attracted the attention of the elegance of technique, originality and the comprehensive analysis of experimental data. In 1935. on the basis of this work, he defended his thesis and received his doctorate in physics and mathematics.
At the invitation of Vavilov in 1934. F. enrolled in the Physics Institute. P.N. Lebedev, USSR Academy of Sciences in Moscow, where he worked since. Vavilov insisted that F. switched to atomic physics. Together with his colleague L.V. Grosheva F. conducted a thorough comparison of theory and experimental data concerning the recently discovered phenomenon, which consisted in the appearance of electron-positron pair under the influence of gamma radiation on Krypton.
. Around the same time, Pavel Cherenkov, one of the graduate students in the Vavilov Institute of
. Lebedeva, began a study of blue luminescence (later called Cerenkov radiation and Vavilov - Cherenkov radiation) arising in the refracting media under the influence of gamma-rays. Cherenkov showed that the radiation was not another kind of luminescence, but he could not explain his theory. In 1936 ... 1937. F. and Igor Tamm able to calculate properties of an electron moving uniformly in some medium at a speed exceeding the speed of light in this environment (something resembling a boat that moves through the water faster than it has generated waves). They found that in this case the radiated energy and the angle spread of the emerging wave can be expressed simply by the electron velocity and the speed of light in this environment and in vacuum.
One of the first triumphs of the theory F. and Tamm was an explanation of the polarization of Cherenkov radiation, which, unlike the case of luminescence, was parallel to the incident radiation, rather than perpendicular to it. The theory seemed so good, . that F., . Tamm and Cherenkov experimentally verified some of its predictions, . such, . as the presence of some energy threshold for the incident gamma, . dependence of this threshold on the refractive index and shape of the emerging radiation (hollow cone with axis along the direction of the incident radiation),
. All these predictions were confirmed. In recognition of this work F. in 1946. was elected a corresponding member of USSR Academy of Sciences, and together with Tamm, Cherenkov and Vavilov was awarded the State Prize of the USSR.
The three surviving members of this group (Vavilov died in 1951) were in 1958. awarded the Nobel Prize in Physics "for the discovery and interpretation of the Cherenkov effect '. In his Nobel lecture F. pointed out that the Cherenkov effect 'has many applications in particle physics, high energy'. 'It was also discovered the link between this phenomenon and other problems - he added - as, for example, the connection with plasma physics, astrophysics, the problem of generating radio waves and the problem of particle acceleration. "
Study F. Cherenkov effect marked the beginning of his long interest in the influence of optical properties of the medium on the radiation of a moving source and one of his articles on the Cerenkov radiation appeared already in 1980. One of the most important contributions F. in this area was a theory of transition radiation, which he formulated, together with the Soviet physicist V.L. Ginsburg in 1945. This type of radiation is due to the restructuring of the electric field of a uniformly moving particle when it crosses the boundary between two media with different optical properties. Although this theory was later verified experimentally, some of its important consequences could not be detected by laboratory methods is more than a dozen years.
. In optics, among other scientific interests of the FA, especially during the Second World War, may be called nuclear physics
. In the mid 40-ies. he performed theoretical and experimental work on the spread and increase the number of neutrons in uranium-graphite systems, and thus contributed to the creation of the atomic bomb. He also thought about the emergence of experimental neutron interactions with light nuclei, as in the interactions between high-speed neutrons, and various nuclei.
In 1946, Mr.. F. organized atomic nucleus laboratory at the Institute of. Lebedev and became its leader. As with 1940. professor at Moscow State University, F. from 1946 to 1956. headed the laboratory of radioactivity at the Research Institute of Nuclear Physics at Moscow State University.
A year later, under the direction of F. the laboratory of neutron physics in the Joint Institute for Nuclear Research in Dubna. Here in 1960. was launched by pulsed fast reactor for spectroscopic studies of neutron. In 1977. went into operation a new and more powerful pulsed reactor.
Colleagues felt that F. possessed a depth and clarity of thinking, the ability to open the merits of the most elementary methods, as well as a special intuition for the most trudnopostigaemyh matters experiment and theory. His research papers are extremely valued for their clarity and logical clarity.
In 1937, Mr.. F. married Ella Abramovna Beylihis, a prominent historian. Their only child, Alexander, became a specialist in neutron physics.
F. received numerous awards of the Soviet government, including the Lenin Prize, two Orders of Lenin, the Order of Labor Red Banner, Order of the October Revolution, as well as the gold medal of the Academy of Sciences of the USSR Vavilov. He was elected academician of the USSR in 1968