Emilio G. Segrè

Emilio Gino Segrè
Born	1 February 1905(1905-02-01) Tivoli, Italy
Died	22 April 1989(1989-04-22) (aged 84)
Institutions	Los Alamos National Laboratory University of California, Berkeley University of Palermo University of Rome La Sapienza
Alma mater	University of Rome La Sapienza
Doctoral advisor	Enrico Fermi
Doctoral students	Samarendra Nath Ghoshal
Known for	Discovery of the antiproton Discovery of technetium Discovery of astatine
Notable awards	Nobel Prize in Physics (1959)
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Emilio Gino Segrè (1 February 1905 – 22 April 1989) was an Italian-born, naturalized American, physicist and Nobel laureate in physics, who with Owen Chamberlain, discovered antiprotons, a sub-atomic antiparticle.

Biography

Segrè was born into a Sephardic Jewish family in Tivoli, near Rome, and enrolled in the University of Rome La Sapienza as an engineering student. He switched to physics in 1927 and earned his doctorate in 1928, having studied under Enrico Fermi.

After a stint in the Italian Army from 1928 to 1929, he worked with Otto Stern in Hamburg and Pieter Zeeman in Amsterdam as a Rockefeller Foundation fellow in 1930. Segrè was appointed assistant professor of physics at the University of Rome in 1932 and served until 1936, becoming one of Via Panisperna boys. From 1936 to 1938 he was Director of the Physics Laboratory at the University of Palermo. 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. After careful chemical and theoretical analysis, Segrè was able to prove that some of the radiation was being produced by a previously unknown element, dubbed technetium, and was the first artificially synthesized chemical element which does not occur in nature.

He was a colleague and close friend of Ettore Majorana, who disappeared mysteriously in 1938.

While Segrè was on a summer visit to California in 1938, Benito Mussolini's fascist government passed anti-Semitic laws barring Jews from university positions. As a Jew, Segrè was now rendered an indefinite émigré. At the Berkeley Radiation Lab, Lawrence offered him a job as a Research Assistant—a relatively lowly position for someone who had discovered an element—for US$300 a month. However, in Segrè's recollection, when Lawrence learned that Segrè was legally trapped in California, he reduced his salary to US$116 a month which many, including Segrè, saw as exploiting the situation. Segrè also found work as a lecturer of the physics department at the University of California, Berkeley.

While at Berkeley, he helped discover the element astatine and the isotope plutonium-239 (which was later used to make Fat Man, the atom bomb dropped on Nagasaki). He found in April 1944 that Thin Man, the proposed plutonium "gun-type" bomb, would not work (because of the presence of Pu-240 impurities), and priority was given to Fat Man, the plutonium "implosion" bomb.

Segrè's ID badge photo from Los Alamos.

From 1943 to 1946 he worked at the Los Alamos National Laboratory as a group leader for the Manhattan Project. In 1944, he became a naturalized citizen of the United States. He taught at Columbia University, University of Illinois and University of Rio de Janeiro. On his return to Berkeley in 1946, he became a professor of physics and of the history of science, serving until 1972.

Professors Emilio Segrè and Owen Chamberlain were co-heads of a research group at the Lawrence Radiation Laboratory. Their group proposed the experiment to discover the anti-proton and this was the chief reason that the Bevatron was built at LRL. The Bevatron was designed to reach proton energies of 6.2 $m_0 c^2$ where m_o is the rest mass of the proton. With the new Bevatron, the Segrè/Chamberlain group produced the first anti-proton (as seen in bubble chamber pictures) and the two shared the 1959 Nobel Prize in Physics for their work.

In 1970, Segrè published a biography of Fermi (Enrico Fermi: Physicist, University of Chicago Press)

In 1974 he returned to the University of Rome as a professor of nuclear physics.

Segrè was also active as a photographer, and took many photos documenting events and people in the history of modern science. The American Institute of Physics named its photographic archive of physics history in his honor. Segrè died at the age of 84 of a heart attack.

See also

• List of Jewish Nobel laureates
• I ragazzi di via Panisperna (movie)

References

• E. Segrè (1993) A Mind Always in Motion: the autobiography of Emilio Segrè, University of California Press [ISBN 0520076273].

Further reading

• Segre, E; et.al. “Formation of the 50-Year Element 94 from Deuteron Bombardment of U{sup 238}”, (June 1942), Argonne National Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission).
• Segre, E. “Spontaneous Fission”, (November 22, 1950), Radiation Laboratory, Lawrence Berkeley National Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission).
• E. Segrè (1953) Experimental Nuclear Physics.
• Segre, E; et.al. “Observation of Antiprotons”, (October 19, 1955), Radiation Laboratory, Lawrence Berkeley National Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission).
• Segre, E; et.al. “Antiprotons”, (November 29, 1955), Radiation Laboratory, Lawrence Berkeley National Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission).
• Segre, E; et.al. “The Antiproton-Nucleon Annihilation Process (Antiproton Collaboration Experiment)”, (September 10, 1956), Radiation Laboratory, Lawrence Berkeley National Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission).
• Segre, E; et.al. “Experiments on Antiprotons: Antiproton-Nucleon Cross Sections”, (July 22, 1957), Radiation Laboratory, Lawrence Berkeley National Laboratory, United States Department of Energy (through predecessor agency the Atomic Energy Commission).
• E. Segrè (1964) Nuclei and Particles
• E. Segrè (1970) Enrico Fermi, Physicist, University Of Chicago Press.
• E. Segrè (1980) From X-rays to Quarks: Modern Physicists and Their Discoveries (Dover Classics of Science & Mathematics), Dover Publications.
• E. Segrè (1984) From Falling Bodies to Radio Waves: Classical Physicists and Their Discoveries.

External links

• Biography and Bibliographic Resources, from the Office of Scientific and Technical Information, United States Department of Energy
• National Academy of Sciences biography
• 1959 Nobel Prize in Physics
• Emilio G. Segrè
• Annotated bibliography for Emilio Segre from the Alsos Digital Library for Nuclear Issues
• Oral History interview transcript with Emilio G. Segre 13 February 1967, American Institute of Physics, Niels Bohr Library and Archives