Wolfgang Paul
1913–1993, Lorenzkirch, Saxony, Germany, Bonn, Germany
German physicist who shared the 1989 Nobel Prize in Physics for inventing the radiofrequency quadrupole ion trap (Paul trap).
Born in Lorenzkirch, Saxony, and raised in Munich, Paul studied in Munich and Berlin, completing his PhD in 1940 under Hans Kopfermann. During the war he worked on isotope separation. At Bonn, where he was professor from 1952 to his death, he invented in 1953 — with Helmut Steinwedel — the quadrupole mass filter and the rf ion trap ('ion cage') that bear his name. He directed CERN's nuclear physics division (1965–1967), built electron synchrotrons at Bonn, and signed the 1957 Göttingen Manifesto against nuclear armament of West Germany.
Nobel-winning work
Paul's invention exploits an alternating quadrupole electric field: ions injected between four rf-driven rods (the quadrupole mass filter, 1953) or into a ring-and-endcap geometry (the 3D Paul trap) follow stable oscillatory trajectories and can be confined for days without material walls.
Published in 1953–1958, the technique gave physicists isolated particles at rest for hours — enabling precision mass spectrometry, storage spectroscopy, and eventually single-ion experiments, optical frequency standards and quantum information processing.
Workplaces: University of Bonn, CERN
Germany