Karl Manne Georg Siegbahn ForMemRS was a Swedish physicist who was awarded the Nobel Prize in Physics in 1924 "for his discoveries and research in the field of X-ray spectroscopy".
Siegbahn was born in Ã–rebro, Sweden. He obtained his Ph.D. at the Lund University in 1911, his thesis was titled Magnetische Feldmessungen. He was acting professor for Johannes Rydberg when his health was failing, and succeeded him as full professor in 1920.
Following his Ph.D., he started research on X-ray spectroscopy. This work continued when he moved to the University of Uppsala in 1923. He developed improved experimental apparatus which allowed him to make very accurate measurements of the X-ray wavelengths produced by atoms of different elements. He developed a convention for naming the different spectral lines that are characteristic to elements in X-ray spectroscopy, the Siegbahn notation. Siegbahn's precision measurements drove many developments in quantum theory and atomic physics.
In 1937, Siegbahn was appointed Director of the Physics Department of the Nobel Institute of the Royal Swedish Academy of Sciences. In 1988 this was renamed the Manne Siegbahn Institute. The institute research groups have been reorganized since, but the name lives on in the Manne Siegbahn Laboratory hosted by Stockholm University.