Aleksandr Chudakov
Alexander Jewgenjewitsch Tschudakow (Russian: Александр Евгеньевич Чудаков, scientific transliteration: Aleksandr Evgenevič Čudakov, English transcription: Aleksandr Evgen'evich Chudakov, born June 16, 1921 in Moscow, † 25 January 2001) was a Russian physicist who experimentally on the field of cosmic radiation worked.
Life and work
Tschudakow was born the son of the engineer and scientist Yevgeny Alexeyevich Tschudakow ( 1890-1953 ). After leaving school he studied physics from 1939 at the Lomonosov University in Moscow. Interrupted by the Second World War, he was able to complete his studies until 1948. As early as 1946 he worked at the Lebedev Institute of the Soviet Academy of Sciences, specifically in the group dealt with the measurement of cosmic radiation. From 1947 to 1951 he measured in a series of rocket experiments, the intensity of the cosmic radiation above the Earth's atmosphere. With a thesis on the analysis of these experiments it was established in 1953 doing a PhD candidate of sciences. In 1949, he understood that the mutual shielding of the fields of an electron and a positron leads to decreased ionization of a high-energy electron-positron pair. This phenomenon is called today Tschudakow effect ( or King -Perkins Tschudakow effect). It also occurs in quantum chromodynamics when the color charge of two quarks or gluons is screened near, and there is as "color transparency " (color transparency ) refers.
From 1953 examined Tschudakow the Cherenkov radiation from air showers. In preparing this experiment he pointed for the first time in 1945 predicted by Vitaly Ginsburg and Ilya Frank transition radiation experimentally by. From 1957 to 1960 Tschudakow developed the first water calorimeter for the detection of Cherenkov radiation. It contained 100 tons of water and can be seen as a forerunner of modern Tscherenkowwasserdetektoren like Super - Kamiokande. 1961 beat Tschudakow and Georgi Sazepin right to use Cherenkov radiation of atmospheric showers to search for sources of high- energy gamma rays (about 1 TeV ), and so founded the gamma-ray astronomy with. Tschudakow designed the first Cherenkov gamma-ray telescope, which ran until 1963 in Katsiveli 1960 on the Crimean Peninsula, but could not detect gamma radiation sources.
After the launch of the first Sputnik in 1957, a new opportunity to study cosmic rays and Tschudakow opened returned to this area of research. For a series of papers on the subject, he received in 1960, together with Sergei Nikolayevich Wernow the Lenin Prize for " the discovery and investigation of the outer radiation belt around the earth " (known as the Van Allen belts ). With a work on this subject he was in 1959 " Doctor of physico- mathematical sciences " (equivalent to the German Habilitation ) doctorate. From 1963 Tschudakow worked on the preparation for the underground Baksan neutrino observatory to study cosmic muons and neutrinos. This scintillation telescope went into operation in 1978 and set upper limits on neutrino oscillations, which has long remained the best in the world. After adjustments in design, it looked for the hypothetical proton decay and also put there a new barrier of 1.25 · 1030 years for neutrinoless decay channels, which was soon improved by other groups. The boundaries for the search for superheavy magnetic monopoles and neutrinos from neutralino annihilation were prepared by the Baksan Neutrino Observatory.
Tschudakow delivered before Eugene N. Parker, based on astrophysical arguments an estimate for the upper limit of the flux of magnetic monopoles, so that one the " Parker limit" should actually call " Tschudakow -Parker limit". From 1971 Tschudakow worked for the Institute for Nuclear Research of the Soviet Academy of Sciences, which was spun off from the Lebedev Institute. He conducted the experiment Kover, which examined 1974 air showers. He also proposed the mid-1960s first Baikal ago to build an underwater muon detector. Building the underwater neutrino telescope NT -200 was built on this idea there. His idea to measure snow reflected Cherenkov air showers with aircraft, was not realized by him.
Tschudakow been corresponding since 1966 and since 1987 full member of the Soviet Academy of Sciences and was also sitting in the presidium. He was awarded the Lenin Prize and the State Prize. He was secretary and later chairman of the Commission on Cosmic Rays of the International Union of Pure and Applied Physics. For twenty years he led the Science Committee on Cosmic Rays of the Russian Academy of Sciences. He taught from the 1950s, experimental nuclear physics at the Lomonosov University in Moscow.
Tschudakow was married and had two children.