Kai M. Siegbahn#

Kai Siegbahn, Nobel Laureate Physics 1981 "for his contribution to the development of high-resolution electron spectroscopy", died on July 20, 2007.

Obituary in The New York Times.

Kai M. Siegbahn was the son of Karl Manne Georg Siegbahn (3 December 1886 - 26 September 1978) who was a Swedish physicist, and Nobel Laureate in Physics 1924 for his discoveries and research in the field of X-ray spectroscopy.