German nuclear physicist who made fundamental contributions to molecular beam spectroscopy, mass spectrometry, and electron acceleration technology. He was awarded the Nobel Prize for Physics in 1989 for his development of the ion trap, or ‘Paul trap’, used to store single atoms long enough to make accurate spectroscopic measurements on them. He shared the award with US scientists Norman Ramsey and Hans Dehmelt.
In 1957 he helped found the DESY accelerator laboratory in Hamburg which has made important contributions to particle physics. From 1964–67, Paul was director of the nuclear physics laboratory of CERN, the joint European laboratory in particle physics in Geneva.
Paul was trained at the Munich and Berlin Institutes of Technology and obtained his MSc in 1937, examined by Hans Geiger (who invented the Geiger counter). In 1939 Paul obtained his doctorate in Kiel. At this time he had a close association with the distinguished spectroscopist Hans Kopfermann and the theoretical physicist Richard Becker. These men were both non-Nazis and, under their influence, Paul took no part in projects, such as the German atom-bomb research, which had military applications. As a result, Paul was one of the few German physicists of his generation untainted by the war years.
In 1952 Paul became professor and director of the Physics Institute at the University of Bonn, Germany, a post that he held until he retired in 1981. At Bonn, he developed the sextupole focusing of molecular beams, the radio frequency quadrupole mass spectrometer and the ion trap. With colleagues he built two electron accelerators.