Bruno di Massimo Pontecorvo (August 22, 1913 - September 25, 1993) was a nuclear physicist noted in exploration geophysics for his invention of the neutron logging method. Pontecorvo was notorious for his Cold War defection to the Soviet Union in 1950. As a physicist in the Soviet Union, he was highly respected, particularly for his work with neutrinos.
Bruno Pontecorvo was born in Marina di Pisa August 22, 1913, the fourth of eight children of a secular Jewish textile merchant. The racial laws adopted under Musolini's regime would later force four of the children to emigrate, and prevent Bruno Pontecorvo from returning to Italy in 1940.
Early Years and Education
At a young age he studied Engineering for two years at the University of Pisa. At the age of 18 he enrolled in his third year of Physics at the University of Rome. His classmates were Enrico Fermi], Franco Rasetti, Oscar D'Agostino, Eduardo Amaldi, and Emilo Segrè. In 1934 the team of Amaldi, D'Agostino, Rasetti, Fermi, and Pontecorvo conducted experiments in slowing neutrinos with buffers (such as paraffin), which led to research on induced radioactivity and nuclear fission.
Pontecorvo moved to Paris in 1936, where he worked with Irène Curie and Frederic Joliot studying the impact of neutrons with protons and electromagnetic transitions between nuclear isomers. It was during his time in France that Pontecorvo became interested in Marxism/communist politics. In 1938 Pontecorvo won the Curie-Carnegie Prize for his work in nuclear phosphorescence. His research was funded for the next year by the French National Research Council (CNRS).
In advance of the German invasion of Paris in 1940, Pontecorvo emigrated to the United States. Prior to his departure he married Marianne Nordblom, with whom he had become romantically involved two years earlier.
In 1941 Pontecorvo published his classic paper on radioactive analyses of oil well samples, which formed the basis of the neutron logging method, while employed by Well Surveys Inc. in Tulsa.
Likely because of his communist sympathies Pontecorvo was not asked to participate in the Manhattan Project (the development of the first atomic bombs). In 1943 Pontecorvo was invited to join the Canadian nuclear reactor project at Chalk River. He worked there on reactors for six years.
In 1948 Pontecorvo obtained British citizenship and was called by John Cockcroft to participate in the British atomic bomb project and 1949 Pontecorvo and his family moved to Harwell, UK.
Defection to the Soviet Union
In August 1950, Pontecorvo, his wife, and three small sons left for a vacation in Italy. They had planned to visit his parents in Chamonix, France, and later to visit Marianne's in Stockholm. However, the Pontecorvos made an unexpected detour to Helsinki, and disappeared. It was suspected that Pontecorvo had defected to the Soviet Union.
Once in the Soviet Union, Pontecorvo changed his name to Bruno Maksimovic Pontekorvo. At a press conference in 1955, Pontecorvo revealed his defection.
Years in the Soviet Union
While in the USSR, Pontecorvo was a highly respected research physicist. Pontecorvo continued his research at the Joint Institute of Nuclear Physics (JINR) at Dubna, in the field high-energy particles and in particular on the decay of the muon and neutrino. He was awarded the Stalin Prize in 1953 and was inducted into the prestigious Soviet Academy of Sciences in 1958. Pontecorvo received the Lenin Prize in 1963. He was awarded the Order of Lenin in 1983. Pontecorvo taught particle physics at Moscow State University.
In an interview with the Independent, Pontecorvo expressed regret at his naiveté in believing the promises of the communist system. Pontecorvo was suspected of having spied for the Soviet Union, but this was never proven, nor did he ever admit to any such activities, nor was it clear that if he did engage in espionage that he could have relayed any information that was sufficiently sensitive to have been a security threat.
After a long and fruitful career as a research physicist Pontecorvo died in 1993, afflicted with Parkinson's disease.
In 1995 the JINR established the presigious Pontecorvo Prize. The prize is awarded annually by the JINR to the physicist that makes the greatest contribution to nuclear and/or particle physics in the previous year.
- Amaldi, E., D ’Agostino, O., Fermi, E., Pontecorvo, B., Rasetti, F., and Segre, E., (1935), Artificial radioactivity produced by neutron bombardment: Proc. Royal Soc. of London, Series A, n.868, v.149, pp.522-558.
- Bruno Pontecorvo (1942) RADIOACTIVITY ANALYSES OF OIL WELL SAMPLES. GEOPHYSICS 7(1), 90-94. doi: 10.1190/1.1444997
- Close, F. (2015) Half-Life: The Divided Life of Bruno Pontecorvo, Physicist or Spy Basic Books.
- Turchetti, S. (2012) The Pontecorvo Affair: A Cold War Defection and Nuclear Physics, University of Chicago Press.