The discovery of technetium occurred in 1937 after Emilio G. Segrè analyzed a molybdenum strip sent from Ernest O. Lawrence’s cyclotron in Berkeley. This achievement marked the first time a chemical element was artificially synthesized. Segrè, a physicist who bridged European traditions and American laboratory infrastructure, became central to major twentieth-century breakthroughs in nuclear science and subatomic particle research.
Academic Formation and Early Work
Born in 1905 in Tivoli, Segrè began his studies at Sapienza University of Rome in 1922. Initially an engineering student, he transitioned to physics after meeting Enrico Fermi and Franco Rasetti. He completed his degree in 1928 with a thesis on anomalous dispersion. Following military service in the Italian Army, he joined the laboratory on Via Panisperna, becoming a colleague of Fermi. His early research included studies on the Zeeman effect and space quantization, which he pursued through fellowships in Amsterdam and Hamburg under Otto Stern.
The Palermo Years and Technetium
In 1936, Segrè accepted a position as professor of physics and director of the Physics Institute at the University of Palermo. Despite the lack of modern equipment, he continued collaborative research. His 1937 analysis of a radioactive molybdenum strip, conducted with mineralogist Carlo Perrier, provided the empirical proof for technetium. This discovery demonstrated his capability to bridge theoretical physics with precise chemical identification, establishing his reputation within the global scientific community.
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The implementation of antisemitic laws by the Italian government in 1938 forced Segrè into exile as he was of Jewish descent. He relocated to the United States, finding employment at the Berkeley Radiation Laboratory. During this period, he contributed to the discovery of astatine and the isotope plutonium-239. From 1943 to 1946, he served as a group leader at the Los Alamos National Laboratory for the Manhattan Project. His analysis identified that the Thin Man plutonium gun-type weapon design would fail due to plutonium-240 impurities.
Antiproton Research and Later Career
After becoming a naturalized U.S. citizen in 1944, Segrè returned to the University of California, Berkeley, in 1946, where he taught physics and the history of science until 1972. This work earned him the Nobel Prize in Physics in 1959, shared with Owen Chamberlain. Outside of his formal academic duties, he maintained an archive of photographs documenting the history of modern science.
Fast facts
- Born: 1905, Tivoli
- Died: 1989, Lafayette
- Nobel Prize in Physics: 1959
- Notable Discoveries: Technetium, Astatine, Antiproton
- Education: Sapienza University of Rome
- Citizenship: United States; Kingdom of Italy
- Major Affiliation: University of California, Berkeley
Questions readers ask
What elements did Emilio G. Segrè discover?
He is credited with the discovery of technetium and astatine.
What role did he play in the Manhattan Project?
He served as a group leader at Los Alamos, where he determined that the Thin Man weapon design was impractical due to plutonium impurities.
Did he receive any major scientific honors?
Yes, he was awarded the Nobel Prize in Physics in 1959, the August Wilhelm von Hofmann Medal in 1953, and the Richtmyer Memorial Lecture Award in 1957.
Achievements
- Nobel Prize in Physics — 1959
- Affiliated with University of California, Berkeley, University of Palermo and Sapienza University of Rome
- Educated at Sapienza University of Rome
- Worked as physicist, university teacher and nuclear physicist
