PONTECORVO, BRUNO (1913–1993), Italian nuclear physicist. Born in Italy, Pontecorvo studied at Pisa University and at Rome University, where he taught from 1933 to 1936. He then served with scientific institutions in France and in 1940 moved to the U.S., where he worked as an expert in radio-graphic prospecting for oil. In 1943 he became a member of the Anglo-Canadian atomic energy team in Montreal and worked under the Nobel prizewinner Enrico Fermi in the Chalk River atomic project, participating in research leading to the development of neutron physics. From 1948 he was in England as an associate in the Harwell Atomic Research Laboratory. In 1950 Pontecorvo defected to the Soviet Union, where he was put in charge of a team at the Joint Nuclear Research Institute. He became a member of the U.S.S.R. Academy of Sciences and won the Lenin Prize and Order of Lenin (both in 1963).
His main fields of research were neutron physics (1943–48), the production of pi-mesons from neutrons (1950–55), and the interaction of pi-mesons with nucleons. Among his publications are "Artificial Radioactivity Produced by Neutron Bombardment" (in Proceeding of the Royal Society of London, 1935); "Isomérie nucléaire produite par les rayons × du spectre continu" (with A. Lazard, in Comptes rendus des séances de l'Académie des Sciences, Paris, 1939); O protsessakh obrazovaniya tyazholykh mezonov i chastits ("Production Processes of Heavy Mesons and Particles," 1955); and Slabye vzaimodeystviya elementarnykh chastits i neytrinov ("Weak Interactions of Elementary Particles and Neutrinos," 1963).
A.M. Moorehead, The Traitors: The Double Life of Fuchs, Pontecorvo and Nunn May (1952); Prominent Personalities in the U.S.S.R. (1968), S.V.