Born Sept. 18, 1907, in Redondo Beach, Calif. American physicist.
In 1928, McMillan graduated from the California Institute of Technology in Pasadena. In 1935 he began working at the radiation laboratory of the University of California, becoming the laboratory’s director in 1958. He also became a professor at the university in 1946. His main works are devoted to nuclear physics and to the technology involved in the acceleration of elementary particles. In 1940, McMillan discovered the first transuranium element, neptunium, by irradiating a uranium target with neutrons; he was also co-discoverer of plutonium (1940-41). In 1945, somewhat later than but independently of V. I. Veksler, he proposed the principle of phase stability in accelerators. McMillan received a Nobel Prize in 1951 with G. Seaborg.