Born on 10 August 1913 in Lorenzkirch, Germany, Wolfgang Paul was a Nobel Prize–winning physicist known for his development of the ion trap technique. Not to be confused with his Austrian contemporary, Wolfgang Pauli, Paul grew up in Munich and studied at the technical universities of both Munich and Berlin. With the advent of World War II, Paul was drafted briefly into the air force but got a leave of absence to complete his PhD in physics from the Technical University of Berlin in 1939. Paul spent several years in postdoctoral research under Hans Kopfermann, first at the Technical University of Berlin, then at the University of Kiel, and finally at the University of Göttingen. Paul became an instructor at Göttingen in 1944 and a full professor in 1950. His research focused on mass spectrometry and isotope separation. In 1952 he was appointed professor at the University of Bonn and director of its Physics Institute, with which he would be associated for the next several decades. It was in the 1950s that Paul developed the quadrupole ion trap, or Paul trap, which uses an alternating electric field to isolate and hold charged particles. The invention earned Paul one-half of the 1989 Nobel Prize in Physics. Among the practical uses of the Paul trap was the development of cesium clocks for more precisely measuring time. By the 1960s Paul’s interests had shifted to electron accelerators. He played a leading role in the evolution of CERN and served as its nuclear physics division director from 1965 to 1967. By the 1970s, Paul had turned to neutron physics and magnetic storage rings, and in 1978 he and his colleagues became the first to confine neutral particles electromagnetically. After Paul retired in 1981, he became president of the Alexander von Humboldt Foundation, which grants fellowships for scientists. He died at age 80 in 1993. (Photo credit: AIP Emilio Segrè Visual Archives, W. F. Meggers Gallery of Nobel Laureates Collection)
