Lawrence, Ernest O(rlando) (1901-1958)

US physicist. He was awarded the Nobel Prize for Physics in 1939 for his invention of the cyclotron particle accelerator which pioneered the production of artificial radioisotopes, the study of elementary particle interactions, and the synthesis of new transuranic elements.

During World War II Lawrence was involved with the separation of uranium-235 and plutonium for the development of the atomic bomb, and he organized the Los Alamos Scientific Laboratories at which much of the work on this project was carried out. After the war, he continued as a believer in nuclear weapons and advocated the acceleration of their development.

Lawrence was born in South Dakota and studied there and at Minnesota, Chicago, and Yale universities. He was professor of physics at the University of California, Berkeley, from 1930 and director from 1936 of the Radiation Laboratory, which he built into a major research centre for nuclear physics. The first cyclotrons were made in 1930 and were only a few centimetres in diameter. Each larger and improved design produced particles of higher energy than its predecessor, and a 68-cm/27-in model was used to produce artificial radioactivity. Among the results obtained from the use of the accelerated particles in nuclear transformations was the disintegration of the lithium nucleus to produce helium nuclei.