Segrè, Emilio Gino (1905–1989)

Italian-born US physicist who was awarded the Nobel Prize for Physics in 1959 for his discovery in 1955 of the antiproton, a new form of antimatter. He shared the award with his co-worker Owen Chamberlain. Segrè discovered the first synthetic element, technetium (atomic number 43), in 1937.

Segrè was born near Rome and studied there, working with Enrico Fermi. Segrè became professor at Palermo in 1936 but was forced into exile by the fascist government and, apart from wartime research at Los Alamos, New Mexico, worked from 1938 at the University of California at Berkeley, where he became professor in 1947.

In 1940 Segrè discovered another new element, now called astatine (atomic number 85). He again met up with Fermi, now at Columbia University, to discuss using plutonium-239 instead of uranium-235 in atomic bombs. Segrè began working on the production of plutonium at Berkeley and then moved to Los Alamos to study the spontaneous fission of uranium and plutonium isotopes.

In 1947, Segrè started work on proton–proton and proton–neutron interaction, using a cyclotron accelerator at Berkeley. This was how he detected the antiproton, which confirmed the relativistic quantum theory of English physicist Paul Dirac.