Emilio Segre

Emilio Segre was an Italian-American physicist who discovered two new chemical elements and, later in his career, a fundamental subatomic antiparticle. Segre trained under Enrico Fermi in Rome, and in 1937, working with chemist Carlo Perrier in Palermo, he identified technetium, element 43, the first chemical element ever to be artificially produced rather than found in nature, created by bombarding molybdenum with deuterons in a cyclotron; Segre later also contributed to the discovery of the element astatine. After emigrating to the United States, Segre joined the wartime Manhattan Project at Los Alamos, working on plutonium research relevant to the atomic bomb. In 1955, leading a research group at the Lawrence Radiation Laboratory in Berkeley alongside physicist Owen Chamberlain, Segre used the newly built Bevatron particle accelerator to produce and identify the antiproton, the antimatter counterpart of the proton, confirming a prediction of relativistic quantum theory and opening the door to the discovery of many further antiparticles; Segre and Chamberlain shared the 1959 Nobel Prize in Physics for this work. Segre spent much of his career as a professor at the University of California, Berkeley, and also wrote extensively on the history of twentieth century physics.