Bruno Pontecorvo

The family was Jewish and non-observant, from Rome on his father's side and from Mantua - on his mother's. His grandfather on the maternal side, Arrigo Maroni (1852–1924), born in Mantua, was director of the Fatebenefratelli Hospital in Milan; his mother's cousin was a notable zoologist Elisa Gurrieri-Norsa (1868-1939).

His older brother Guido, who was born in 1907, became a geneticist.

Another older brother Paolo, who was born in 1909, became an engineer who worked on radar during World War II.

His older sister Giuliana was born in 1911.

Bruno Pontecorvo (Бру́но Макси́мович Понтеко́рво, Bruno Maksimovich Pontecorvo; 22 August 1913 – 24 September 1993) was an Italian and Soviet nuclear physicist, an early assistant of Enrico Fermi and the author of numerous studies in high energy physics, especially on neutrinos.

Pontecorvo was born on 22 August 1913 in Marina di Pisa, the fourth of eight children of Massimo Pontecorvo and his wife Maria Maroni.

His younger brother Gillo was born in 1919, and is best known as the director of The Battle of Algiers.

He also had two younger sisters; Laura, who was born in 1921, and Anna, who was born in 1924, and a younger brother Giovanni, who was born in 1926.

His family was a wealthy family; Massimo owned three textile factories employing over 1,000 people.

He enterered the University of Pisa intending to study engineering, but after two years he decided to switch to physics in 1931.

On the advice of his brother Guido, he decided to study at the University of Rome La Sapienza, where Enrico Fermi had gathered together a group of promising young scientists known as the Via Panisperna boys after the name of the street where the Institute of Physics of Rome University was then situated.

At the age of 18 he was admitted to the third year of Physics.

Fermi described Pontecorvo as "scientifically one of the brightest men with whom I have come in contact in my scientific career".

As their youngest member, the group nicknamed him Cucciolo, which means "puppy".

In 1934 he participated in Fermi's famous experiment showing the properties of slow neutrons that led the way to the discovery of nuclear fission.

In 1934, Pontecorvo contributed to Fermi's famous experiment showing the properties of slow neutrons that led the way to the discovery of nuclear fission.

Pontecorvo's name was included on the Via Panisperna boys' patent "To increase the production of artificial radioactivity with neutron bombardment".

He was made a temporary assistant at the Royal Institute of Physics on 1 November 1934 and the University of Rome, and on 7 November, he was listed as co-author, along with Fermi and Rasetti, of a landmark paper on slow neutrons that reported that hydrogen slowed neutrons more than heavy elements, and that slow neutrons were more easily absorbed.

An Italian patent was granted for the process in October 1935, in the name of Fermi, Pontecorvo, Edoardo Amaldi, Franco Rasetti and Emilio Segrè.

He moved to Paris in 1936, where he conducted research under Irène and Frédéric Joliot-Curie.

Influenced by his cousin, Emilio Sereni, he joined the Italian Communist Party, whose leader were in Paris as refugees, and as did his sisters Giuliana and Laura and brother Gillo.

The Italian Fascist regime's 1938 racial laws against Jews caused his family members to leave Italy for Britain, France and the United States.

When the German Army closed in on Paris during the Second World War, Pontecorvo, his brother Gillo, cousin Emilio Sereni and Salvador Luria fled the city on bicycles.

He eventually made his way to Tulsa, Oklahoma, where he applied his knowledge of nuclear physics to prospecting for oil and minerals.

A US patent was granted on 2 July 1940.

In 1943, he joined the British Tube Alloys team at the Montreal Laboratory in Canada.

This became part of the Manhattan Project to develop the first atomic bombs.

At Chalk River Laboratories, he worked on the design of the nuclear reactor ZEEP, the first reactor outside of the United States, which went critical in 1945, followed by the NRX reactor in 1947.

He also looked into cosmic rays, the decay of muons, and what would become his specialty, neutrinos.

He moved to Britain in 1949, where he worked for the Atomic Energy Research Establishment at Harwell.

A convinced communist, he defected to the Soviet Union in 1950, where he continued his research on the decay of the muon and on neutrinos.

After his defection to the Soviet Union in 1950, he worked at the Joint Institute for Nuclear Research (JINR) in Dubna.

He had proposed using chlorine to detect neutrinos.

He also predicted in 1958 that supernovae would produce intense bursts of neutrinos, which was confirmed in 1987 when Supernova SN1987A was detected by neutrino detectors.

In a 1959 paper, he argued that the electron neutrino and the muon neutrino were different particles.

Solar neutrinos were detected by the Homestake experiment, but only between one third and one half of the predicted number were found.

In response to this solar neutrino problem, he proposed a phenomenon known as neutrino oscillation, whereby electron neutrinos became muon neutrinos.

The prestigious Pontecorvo Prize was instituted in his memory in 1995.

The fourth of eight children of a wealthy Jewish-Italian family, Pontecorvo studied physics at the Sapienza University of Rome, under Fermi, becoming the youngest of his Via Panisperna boys.

The existence of the oscillations was finally established by the Super-Kamiokande experiment in 1998.