Emilio Segrè

Origins and early life

Emilio Gino Segrè was born on 1 February 1905 in Tivoli, near Rome, and came from an Italian Jewish family: his father Giuseppe owned a paper mill, his mother was Amelia Treves, and he was the youngest of three brothers.

Work and career

He enrolled at La Sapienza in 1922 to read engineering, and in 1927 met Franco Rasetti, who introduced him to Enrico Fermi; with the help of the institute's director he transferred to physics and took his degree under Fermi in 1928, becoming one of the young men known as the Via Panisperna boys. He was appointed assistant professor at Rome in 1932 and director of the physics laboratory at Palermo in 1936. In 1937 a colleague at Berkeley sent him a strip of molybdenum cut from the innards of Ernest Lawrence's cyclotron, which was emitting a radioactivity nobody could account for; separating it chemically, Segrè showed that part of it came from an element that does not exist in nature — technetium, the first element ever made by human hands.

He was visiting Berkeley in 1938 when Mussolini's government passed the racial laws barring Jews from university posts, which turned a summer trip into permanent exile; Lawrence kept him on as an underpaid research assistant, and there he helped find astatine and plutonium-239. He led a group at Los Alamos from 1943, where his measurement of plutonium-240 contamination in April 1944 proved that the intended gun-type plutonium bomb could never work and forced the redesign that produced the implosion device.

Recognition

Back at Berkeley as professor of physics and of history of science, he and Owen Chamberlain built the experiment that in 1955 produced the antiproton, the first antiparticle of matter's heavy component, and the two shared the 1959 Nobel Prize in Physics. He was also a serious photographer of his colleagues, and the American Institute of Physics named its archive of physics photographs after him. He died on 22 April 1989.