Cockcroft, John Douglas

Born May 27, 1897, in Todmorden; died Sept. 18,1967, in Cambridge. British physicist. Member of the Royal Society of London (1936).

Cockcroft studied at the universities in Manchester (1919–22) and Cambridge (1922–27). From 1928 to 1946 he was a fellow at Cambridge University, where he became a professor in 1939. From 1939 to 1944 he directed work on the development of radar air defense. He was director of the Anglo-Canadian atomic energy laboratory in Montreal (1944–46) and director of the Atomic Energy Research Center at Harwell (1946–58). Beginning in 1960 he was master of Churchill College at Cambridge.

In 1924, Cockcroft began working in the Cavendish Laboratory under E. Rutherford. Together with E. Walton he built the first proton accelerator and generated (1932) a nuclear reaction by exposing a lithium target to protons artificially accelerated to 700 MeV. He subsequently studied reactions arising from the action of charged particles on the nuclei of various elements. He was awarded a Nobel Prize (together with Walton) in 1951.