Awarding of the Stalin Prizes for 1948

On April 9 of this year, the decree of the Council of Ministers of the USSR was published on the awarding of Stalin Prizes for outstanding scientific works, outstanding inventions, and fundamental improvements in production methods for 1948. In the list of works honored with Stalin Prizes, research by Soviet physicists occupies an honorable place.

The first-degree prize in the section of the physico-mathematical sciences was awarded to the professor of Moscow State University named after M. V. Lomonosov, head of a sector of the Physical Institute named after P. N. Lebedev of the Academy of Sciences of the USSR, Sergei Nikolaevich Vernov, for experimental investigations of cosmic rays in the upper layers of the atmosphere, set forth in the articles: “Investigation, by means of a hodoscope, of showers of particles produced in lead by cosmic rays in the stratosphere,” “Study of showers of cosmic rays accompanying penetrating particles,” “Measurement of showers produced by cosmic rays in the stratosphere with the aid of an ionization chamber,” “Angular distribution of cosmic rays in the stratosphere,” and “Investigation of the soft and hard components of cosmic rays in the stratosphere.”

The study of cosmic rays in the upper layers of the atmosphere is directly connected with the problem of primary cosmic radiation, which is one of the most pressing and most complex areas in the investigation of cosmic rays. The rapid degradation of the energy of cosmic radiation as it penetrates deep into the atmosphere, and the complexity of the transformations accompanying this penetration, make it impossible to study primary radiation at low altitudes. At the same time, the study of primary radiation is of exceptional interest in connection with the problems of atomic-nucleus physics, for here we are dealing with particles whose energy exceeds by several orders of magnitude the energies attainable under laboratory conditions.

The investigation of cosmic rays at great altitudes required the development of a specific methodology, connected with the need to transmit signals from the measuring apparatus to an observer on the ground by means of radio. S. N. Vernov

is a pioneer in the field of creating such teleapparatus. As early as 1937, they carried out with its aid an extensive investigation of the geomagnetic effect for cosmic rays in the stratosphere, as a result of which it was shown that primary radiation is corpuscular and consists of charged particles. The further development of the original apparatus created by S. N. Vernov, which in his hands reached virtuoso perfection, enabled him to discover a number of new phenomena and to obtain much highly valuable information about primary cosmic radiation.

Thus, S. N. Vernov established that primary radiation, directly or through an agent, creates so-called “special” showers, and traced the variation of these showers with altitude. It turned out that the “special” showers contain electrons and photons. Thereby, apparently, it was possible to approach an explanation of the genesis, still unclear to this day, of the soft component predominating in the atmosphere. At the same time it turned out that if an intermediate particle arises in the process of shower formation, its lifetime must be very short (range less than 10 cm).

The data obtained provide grounds for assuming that “special” showers arise as a result of a nuclear “explosive” process; moreover, it may be expected that they contain a component consisting of strongly ionizing heavy nuclear particles. This leads to the possibility that primary cosmic radiation excites “cascade” nuclear reactions.

The investigation of the effective cross sections corresponding to the “explosive” shower-forming process in primary cosmic radiation for various substances showed that $\sigma_{\mathrm{eff}}$ is approximately equal to the cross section of the nucleus, which indicates an extremely intense interaction of primary radiation with matter: every act of passage of a primary particle through a nucleus is accompanied by an “explosion” of the nucleus. Further, it turned out that $\sigma_{\mathrm{eff}}$ is proportional to $A^{-1/3}$, where $A$ is the atomic weight of the nucleus. This indicates that in the “explosion” a large part of the energy of the primary particle is expended.

In addition, S. N. Vernov discovered the occurrence of secondary radiation when primary radiation passes through 8 cm of lead, the intensity of the secondary radiation being approximately twice as great as the intensity of the primary. Finally, the angular distribution of the intensity of various components of cosmic radiation at great altitudes was investigated. Analysis of these data makes possible the supposition that primary radiation, besides protons, may also include negatively charged particles.

Corresponding Member of the Academy of Sciences of the Ukrainian SSR, head of the laboratory of the Leningrad Physico-Technical Institute of the Academy of Sciences of the USSR, Georgii Dmitrievich Latyshev, was awarded the first prize in the section of physico-mathematical sciences

for experimental studies in the field of the physics of the atomic nucleus, set forth in the articles: “Internal Conversion of Gamma Radiation,” “Fine Structure of Gamma Lines,” “Monochromatic Positrons of Internal Conversion,” and “On the Radioactivity of Beryllium.”

G. D. Latyshev is an outstanding master of experiment. The method for investigating gamma spectra that he has created in recent years, unsurpassed in precision, has made it possible to achieve results that leave far behind the work of foreign scientists in this field.

Of especially great importance is G. D. Latyshev’s discovery of the presence of a “fine structure” in nuclear levels and the proof that the structure of nuclear levels has an ordered character.

The study of the spectrum of conversion electrons for a number of gamma-radiation lines showed that the conversion lines are not monochromatic, but consist of a series of equidistant components. Measurement of the intervals between the components of the multiplet led to a value of the order of 6.2 kilovolts.

The experimentally demonstrated constancy of the magnitude of the multiplet splitting of nuclear levels enabled G. D. Latyshev, by analogy with optical spectra, to put forward the hypothesis that here we are dealing with a rotational structure.

Furthermore, in the spectrum of conversion positrons of RaC, G. D. Latyshev discovered the existence of so-called “monochromatic” positrons. Analysis of the nature of these positrons made it possible to estimate the width of nuclear levels, and quite acceptable values were obtained.

A number of significant conclusions is also furnished by the angular correlation established by G. D. Latyshev between gamma and alpha radiation.

The First Prize in the section of technical sciences was awarded to the well-known physicist, Corresponding Member of the Academy of Sciences of the USSR and Full Member of the Academy of Sciences of the Ukrainian SSR, Georgii Viacheslavovich Kurdiumov, for research in the field of metal science, set forth in the works: “Diffusionless (Martensitic) Transformations in Alloys,” “On the Nature of Diffusionless (Martensitic) Transformations,” and “On the Kinetics of the Transformation of Austenite into Martensite at Low Temperatures.”

G. V. Kurdiumov has been engaged in the study of martensitic structures since 1926. As a result of these extensive investigations, carried out with an exceptional variety of experimental methods, G. V. Kurdiumov was the first to create complete and substantiated conceptions of the nature of martensite and the mechanism of formation of martensitic structures in alloys. In particular, it turned out that martensitic transformations should be regarded as phase transformations.

The development of a general theory of martensitic transformations made it possible to create new, rigorously scientific conceptions of the processes of thermal-

ical treatment in general and, in particular, to reveal the physical nature of such practically important processes as the hardening and tempering of steel.

Along the way, G. V. Kurdyumov discovered isothermal transformations of austenite into martensite at low temperatures (of the order of 0–190° C) and the supercooling of austenite below the martensitic point, as well as the existence of “elastic” crystals of martensite, which grow on cooling and disappear on heating (under a definite temperature regime).

The concepts developed by G. V. Kurdyumov, and the phenomena discovered by him, have outstanding significance not only scientifically but also practically.

A prize of the second degree in the section of physical and mathematical sciences was awarded for the research of Corresponding Member of the Academy of Sciences of the USSR Georgii Abramovich Grinberg in mathematical physics, of great importance for the calculation and design of electronic devices, set forth in the monograph Selected Problems of the Mathematical Theory of Electrical and Magnetic Phenomena.

G. A. Grinberg is one of the foremost specialists in the field of mathematical physics. Among his other outstanding investigations, he was, in particular, the first to formulate and solve the problem of the propagation of radio waves in an inhomogeneous atmosphere.

In the named monograph, G. A. Grinberg, as applied to the fundamental problems of electro- and magnetostatics of homogeneous and inhomogeneous media, the theory of the propagation of currents in spatially extended media, the propagation of electromagnetic waves in media with variable properties, and others, developed two groups of new, very general methods for integrating the equations of mathematical physics.

First of all, this is an original method for integrating equations of mathematical physics with separable variables, based on the expansion of solutions of inhomogeneous equations with inhomogeneous boundary conditions into a series in eigenfunctions of certain homogeneous equations with homogeneous boundary conditions. In contrast to the method of particular solutions, this method, in its structure, is adequate to the problems under consideration and does not require the use of artificial devices. At the same time, it sheds new light on the nature of solutions of equations of this type and makes it possible to embrace various methods from a single point of view.

The second group of methods is a development of the author’s previous work on the application of integral equations and the solution of static problems of the electromagnetic field.

Finally, G. A. Grinberg examined the general theory of focusing and the formative action of electric and magnetic fields on beams of charged particles, as well as questions of the theory of electronic devices when operating in static, high-frequency, and nonstationary regimes.

For scientific research in the field of atmospheric optics, a second-degree prize in the section of the physical and mathematical sciences was awarded to the professor of the N. E. Zhukovsky Air Force Engineering Academy and research worker of the Geophysical Institute of the Academy of Sciences of the USSR, Ivan Andreevich Khvostikov.

I. A. Khvostikov is the foremost specialist in the field of atmospheric optics. He is responsible for a number of outstanding investigations of the luminescence of the night sky (in particular, the green emission line), of the study of the upper layers of the atmosphere by the twilight method and by the method of sounding the atmosphere with a searchlight beam, and also of other problems of atmospheric optics. Thus, he was the first to obtain optical “photographs” of the tropopause, to discover polarization anomalies in the light of the twilight sky and to establish a correlation between the degree of manifestation of these anomalies and the critical frequency of reflection of radio waves; he established the presence of sodium vapors in the troposphere, proposed a method for the direct measurement of the angle of atmospheric refraction, and so on.

Being an excellent experimentalist, I. A. Khvostikov has with unfailing success directed his efforts chiefly toward solving the most complex and urgent problems of atmospheric optics, which require the use of the most advanced and powerful methods of modern physical experiment.

Stalin Prizes for outstanding inventions recognized the works of Academician A. A. Lebedev, N. A. Tolstoy, P. P. Feofilov, V. V. Furduyev, and a number of other physicists who created, or took an active part in creating, various apparatus of great scientific or national-economic importance.