Bruno Pontecorvo
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Bruno Pontecorvo (August 22, 1913 - September 24, 1993) was an Italian atomic physicist, an early assistant of Enrico Fermi and then the author of numerous studies in high energy physics, especially on neutrinos. He became notorious, even outside the scientific community, because of his voluntary move to the USSR in 1950, where he continued his research on the decay of the muon and on neutrinos. The prestigious Pontecorvo Prize was instituted in his memory in 1995.
Biography
Pontecorvo was born in Pisa into a wealthy non-observant Italian Jewish family. At only 18 he was admitted to the Course of Physics held by Enrico Fermi at the University of Rome La Sapienza, becoming one of the closest (and the youngest) assistants of Fermi and one of the so-called Via Panisperna boys (as Fermi's group of scientists is often called, after the name of the street where their laboratory was situated).In 1934 he contributed to Fermi's famous experiment showing the properties of slow neutrons that led the way to the discovery of nuclear fission.
In 1936 he moved to Paris to work in the laboratory of Irène and Frédéric Joliot-Curie on the effects of collisions of neutrons with protons and on the electromagnetic transitions among isomers. During this period he was influenced by the ideas of socialism to which he remained loyal for the rest of his life. In Paris, in 1938, he formed a relationship with Marianne Nordblom, a young student of French Literature, and their first son was born during that year.
Pontecorvo was unable to return to Italy because of the fascist regime's racial discrimination against the Jews. He remained in Paris until the Nazis entered the city, then fled with his family to Spain and shortly after to the USA, where he had found employment with an oil company in Tulsa, Oklahoma. While at the oil company he developed a technology and an instrument for well logging, based on the properties of neutrons. This technology may be considered the first practical application of the Via Panisperna boys' discovery of slow neutrons.
In the USA he was not called upon to participate in the Manhattan Project for the construction of the atomic bomb, possibly because of his committed socialist beliefs. In 1943 he was invited to join Chalk River Laboratories in Canada, where he concentrated on cosmic rays, on neutrinos and on the decay of muons.
In 1948, after he obtained British citizenship, he was invited by John Cockcroft to contribute to the British atomic bomb project and shortly after he was appointed professor at the University of Liverpool.
On August 31, 1950, in the middle of a holiday in Italy, he abruptly left Rome for Stockholm with his wife and three sons without informing friends or relatives. The next day he was helped by Soviet agents to enter the USSR. His abrupt disappearance caused much concern to many of the western intelligence services, especially those of Britain and the USA who were worried about the escape of atomic secrets to the Soviet Union after the then recent case of Klaus Fuchs. But as was pointed out immediately, Pontecorvo had had only limited access to "secret subjects" and even later no allegation of spying or of transferring of secrets to the Soviets has ever been made against him.
In the USSR Pontecorvo was welcomed with honor and given a number of privileges reserved only to the Soviet nomenclature. He worked until his death in what is now the Joint Institute for Nuclear Research (JINR) in Dubna, concentrating entirely on theoretical studies of high energy particles and continuing his research on neutrinos and decay of muons. In recognition of his research he was awarded the Stalin Prize in 1953, membership of the Soviet Academy of Sciences in 1958 and two Orders of Lenin. In 1955 he appeared to the world in public at a press conference where he explained to the world the motivations of his choice to leave the West and work in the USSR. Pontecorvo did not leave the Soviet Union for many years, the first trip being in 1978 when he travelled to Italy.
He died in Dubna in 1993, afflicted by Parkinson's disease.
In 1995, in recognition of his scientific merits, the prestigious Pontecorvo Prize has been instituted by the now Russian Joint Institute for Nuclear Research. The prize, awarded annually to an individual scientist, recognizes "the most significant investigations in elementary particle physics", as acknowledged by the international scientific community.
The scientific work of Bruno Pontecorvo is full of formidable intuitions, some of which have represented milestones in modern physics. These include:
- the intuition of how to detect anti-neutrinos generated in nuclear reactors (methodology used by Frederick Reines who was awarded for this with the Nobel prize in 1995);
- the prediction that neutrinos associated with electrons are different from those associated with muons (for experimental verification of this another Nobel prize was awarded to J. Steinberger, L. Lederman and M. Schwartz in 1988);
- the assumption that neutrinos, in the vacuum, may convert in another type of neutrinos, property known as neutrino oscillations (for which experimental verification a Nobel prize was awarded to M. Koshiba and Ray Davis in 2002).
Selected publications
- Neutron Well Logging - A New Geological Method Based on Nuclear Physics, Oil and Gas Journal, 1941, vol.40, p.32-33.1942.
Books about Bruno Pontecorvo
- M. Mafai - Il lungo freddo: Storia di Bruno Pontecorvo, lo scienziato che scelse l'URSS - Milano, 1992
See also
External links
- [Biography / Scientific Works / Popular Articles / About B. Pontecorvo / Photoalbum] (in English and Russian)
- [1950's news of Pontecorvo's disappearance] from the BBC archive
- [Conscience, Arrogation and the Atomic Scientists] Journal of the Federation of American Scientists, Volume 47, No. 4, July/August 1994
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