Peter Preiswerk (16.01.1907—1972) —Swiss physicist. Born in Basel. Studied at the universities of Basel and Berlin. From 1936 he worked at the Zurich Polytechnic, and from 1952 also at CERN (from 1961 — director of the nuclear physics division).
His work concerned artificial radioactivity, nuclear spectroscopy, neutron physics, nuclear physics and elementary particle physics. Independently of others he discovered (1936) the diffraction of neutrons.