Aleksandr Evgenievich Chudakov (16 June 1921 — 25 January 2001, Moscow

Moscow

Moscow is the capital, the most populous city, and the most populous federal subject of Russia. The city is a major political, economic, cultural, scientific, religious, financial, educational, and transportation centre of Russia and the continent...

) was a Soviet Russian physicist in the field of cosmic-ray physics

Cosmic ray

Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...

, known for Chudakov Effect, the effect of decreasing ionization losses for narrow electron-positron pairs and for experimentally confirming existence of the transition radiation.
He was also the chairman of the IUPAP

International Union of Pure and Applied Physics

The International Union of Pure and Applied Physics is an international non-governmental organization devoted to the advancement of physics...

 Cosmic Ray Commission.

Biography and scientific career

Aleksandr Chudakov was born on 16 June 1921, and graduated from Moscow State University

Moscow State University

Lomonosov Moscow State University , previously known as Lomonosov University or MSU , is the largest university in Russia. Founded in 1755, it also claims to be one of the oldest university in Russia and to have the tallest educational building in the world. Its current rector is Viktor Sadovnichiy...

 (MSU) in 1948
. In 1953 his experimental confirmation of the existence of the transition radiation, which was predicted by Ginzburg

Vitaly Ginzburg

Vitaly Lazarevich Ginzburg ForMemRS was a Soviet theoretical physicist, astrophysicist, Nobel laureate, a member of the Russian Academy of Sciences and one of the fathers of Soviet hydrogen bomb...

 and Ilya Frank

Ilya Frank

Ilya Mikhailovich Frank was a Soviet winner of the Nobel Prize for Physics in 1958 jointly with Pavel Alekseyevich Cherenkov and Igor Y. Tamm, also of the Soviet Union. He received the award for his work in explaining the phenomenon of Cherenkov radiation...

 in 1945, and the effect of decreasing ionization losses for narrow electron-positron pairs, known as the Chudakov Effect, are among Chudakov's famous works. Phenomena similar to Chudakov Effect have been observed in quantum chromodynamics

Quantum chromodynamics

In theoretical physics, quantum chromodynamics is a theory of the strong interaction , a fundamental force describing the interactions of the quarks and gluons making up hadrons . It is the study of the SU Yang–Mills theory of color-charged fermions...

 also.
Chudakov was the author of series of experiments carried out in the 1950s, which focused on investigation of the cosmic rays outside of the atmosphere

Atmosphere

An atmosphere is a layer of gases that may surround a material body of sufficient mass, and that is held in place by the gravity of the body. An atmosphere may be retained for a longer duration, if the gravity is high and the atmosphere's temperature is low...

 with rockets and first satellites. As a result, during the third Soviet sputnik

Sputnik 3

Sputnik 3 was a Soviet satellite launched on May 15, 1958 from Baikonur cosmodrome by a modified R-7/SS-6 ICBM. It was a research satellite to explore the upper atmosphere and the near space, and carried a large array of instruments for geophysical research....

, he discovered the Earth's radiation belts

Van Allen radiation belt

The Van Allen radiation belt is a torus of energetic charged particles around Earth, which is held in place by Earth's magnetic field. It is believed that most of the particles that form the belts come from solar wind, and other particles by cosmic rays. It is named after its discoverer, James...

 in collaboration with S. N. Vernov.

In 1961 Chudakov and G. T. Zatsepin suggested the air Chernkov method for the gamma-ray astronomy

Gamma-ray astronomy

Gamma-ray astronomy is the astronomical study of the cosmos with gamma rays. Gamma-rays are the most energetic form of "light" that travel across the universe, and gamma-rays thus have the smallest wavelength of any wave in the electromagnetic spectrum.Gamma-rays are created by celestial events...

 and carried out a pioneering experiment at Katsively, Crimea

Crimea

Crimea , or the Autonomous Republic of Crimea , is a sub-national unit, an autonomous republic, of Ukraine. It is located on the northern coast of the Black Sea, occupying a peninsula of the same name...

.

From the mid-1960s Chudakov headed the design and construction of the Baksan Underground Scintillation Telescope

Baksan Neutrino Observatory

The Baksan Neutrino Observatory is a scientific laboratory of INR RAS located in the Baksan gorge in the Caucasus mountains in Russia. It started operations in 1977, becoming the first such observatory in the USSR...

, which was put into operation in 1978 and considered to be one of the first large multipurpose facilities for underground physics. In astroparticle physics

Astroparticle physics

Astroparticle physics, the same as particle astrophysics, is that branch of particle physics that studies elementary particles of astronomical origin, and their relation to astrophysics and cosmology. It is a relatively new field of research emerging at the intersection of particle physics,...

the first class results have been obtained with this telescope which is still in operation.