Zatsepin, Georgii Timofeevich

Born May 15 (28), 1917, in Moscow. Soviet physicist; corresponding member of the Academy of Sciences of the USSR (1968). Graduated from Moscow University in 1941. Since 1944 he has worked in the Physics Institute of the Academy of Sciences of the USSR, and since 1963 he has been the director of a labora-tory. He has been a professor at Moscow University since 1958.

Zatsepin’s main works are on the physics of cosmic rays and on neutrino astrophysics. In 1947-49 he developed a method for studying large cosmic-ray showers and, using experimental data, established that the basis for the development of such showers is a nuclear-cascade process, whereas electron-photon processes are secondary. From these data he found a number of characteristics of the elementary event of nuclear collisions at high particle energies and suggested an explanation of these processes (1949-62). He was the first to devote attention to the effects arising during the passage of ultrarelativistic particles through a photon gas. His works from 1960 to 1969 were devoted to the physics of muons and neutrinos, as well as to the methods and prospects of neutrino astrophysics. He has been awarded the State Prize of the USSR in 1951.