Kai Siegbahn

Born on 20 April 1918 in Lund, Sweden, Kai Siegbahn was a physics Nobel laureate known for his contributions to the development of high-resolution electron spectroscopy. His father, Manne Siegbahn, was physics chair at Uppsala University and a 1924 Nobel laureate. From 1936 to 1942, Kai studied mathematics, chemistry, and physics at Uppsala University. He earned his PhD in physics from the University of Stockholm in 1944. He remained in Stockholm over the next decade, working first as a researcher at the Nobel Institute for Physics and then as a physics professor at the Royal Institute of Technology. In 1954 he returned to Uppsala University, where he assumed the physics chair formerly occupied by his father. Siegbahn’s primary contribution was the development and refinement of the technique of electron spectroscopy, used to study the surface chemistry of metals and other materials by bombarding them with x rays and examining the electrons they emit. The technique has found many industrial applications, such as determining corrosion on metals, analyzing the surfaces of catalysts in oil refining, and identifying contaminants on electrical circuits. For this work, Siegbahn shared the 1981 Nobel Prize in Physics with US scientists Arthur Schawlow and Nicolaas Bloembergen. Siegbahn continued to work at the University of Uppsala even after he retired as professor emeritus in 1984. He wrote and edited several books, including the classic text Alpha-, Beta-, and Gamma-Ray Spectroscopy (1965). Over his career, Siegbahn received many international awards and honorary doctoral degrees and was a member of a number of professional societies, including the Royal Swedish Academy of Sciences. He died of a heart attack at age 89 in 2007. (Photo credit: AIP Emilio Segrè Visual Archives, W. F. Meggers Gallery of Nobel Laureates Collection)

Date in History: 20 April 1918