born Aug. 8, 1901, Canton, S.D., U.S.
died Aug. 27, 1958, Palo Alto, Calif.
U.S. physicist.
He earned a Ph.D. at Yale University and taught physics at the University of California at Berkeley from 1929, where he built and directed (from 1936) its radiation laboratory. In 1929 he developed the cyclotron , with which he accelerated protons to speeds high enough to cause nuclear disintegration. He later produced radioactive isotopes for medical use, instituted the use of neutron beams to treat cancer, and invented a colour-television picture tube. He worked with the Manhattan Project , converting the Berkeley cyclotron to separate uranium-235 by mass spectrometry. For his invention of the cyclotron, he was awarded a 1939 Nobel Prize, and in 1957 he received the Enrico Fermi Award. Lawrence Berkeley Laboratory and Lawrence Livermore National Laboratory were named in his honour, as was element 103, lawrencium.