McMillan, Edwin Mattison (1907–1991)

US physicist. In 1940 he discovered neptunium, the first transuranic element, by bombarding uranium with neutrons. He shared the Nobel Prize for Chemistry in 1951 with Glenn Seaborg for their discovery and work in the chemistry of transuranic elements.

In 1943 McMillan developed a method of overcoming the limitations of the cyclotron, the first accelerator, for which he shared, 20 years later, an Atoms for Peace award with I Veksler, director of the Soviet Joint Institute for Nuclear Research, who had come to the same discovery independently.

McMillan was born in Los Angeles and studied at the California Institute of Technology and Princeton. From 1932 he was on the staff at the University of California, as professor 1946–73, except during World War II when he worked on radar and Seaborg took up his work at Berkeley. The discovery of plutonium facilitated the construction of the first atom bomb, in which McMillan also took part.