Emilio Gino Segrè

Emilio Gino Segrè discovered technetium andastatine and antiproton

Emilio Gino Segrè (1 February 1905 – 22 April 1989) was an Italian physicist and Nobel laureate who discovered the elements technetium andastatine, and the antiproton, a sub-atomic antiparticle, for which he was co-awarded the 1959 Nobel Prize in Physics with American Owen Chamberlain. An Antiproton is an antiparticle that has the same mass as a proton but opposite in electrical charge.

He was born in Tivoli, near Rome, and studied engineering at the University of Rome La Sapienza before taking up physics in 1927. Segrè was appointed assistant professor of physics at the University of Rome in 1932 and worked there until 1936. He was Director of the Physics Laboratory at the University of Palermo from 1936 to 1938.

After a visit to Ernest O. Lawrence's Berkeley Radiation Laboratory, he was sent a molybdenum strip from the laboratory's cyclotron deflector in 1937 which was emitting anomalous forms of radioactivity.  Segrè was able to prove that some of the radiation was being produced by a previously unknown element, dubbed technetium, which was the first artificially synthesized chemical element which does not occur in nature.

In 1938, Mussolini's fascist government passed anti-Semitic laws that barred Jews from university positions. Being one, Segrè was now rendered an indefinite émigré. At the Berkeley Radiation Lab, Lawrence offered him a job as a Research Assistant.  Segrè helped discover the element astatine and the isotope plutonium-239, which was later used to make the Fat man atomic bomb dropped on Nagasaki. From 1943 to 1946 he worked at the Los Alamos National Laboratory as a group leader for the Manhattan Project. In April 1944 he found that Thin Man, the proposed plutonium gun-type nuclear weapon could not work due to the presence of plutonium-240 impurities.

He became a naturalized citizen of the United States in 1944. He returned to Berkeley in 1946 and became a professor of physics and of history of science, serving until 1972.  Segrè and Owen Chamberlain were co-heads of a research group at the Lawrence Radiation Laboratory that discovered the antiproton, for which they shared the 1959 Nobel Prize in Physics.

Segrè was also active as a photographer, who took photos documenting events and people in the history of modern science, which were donated to the American Institute of Physics after his death. The American Institute of Physics named its photographic archive of physics history in his honor.

Resources:

• Emilio Segrè.  www.britannica.com. Accessed 1 February 2014.

• Emilio Segrè.  www.nobelprize.org/nobel_prizes/physics/laureates/1959/segre-bio.html.  Accessed 1 February 2014