Cockcroft, John Douglas (1897-1967)

British physicist. In 1932 he and Irish physicist Ernest Walton succeeded in splitting the nucleus of an atom for the first time. For this they were jointly awarded a Nobel prize 1951. The voltage multiplier built by Cockcroft and Walton to accelerate protons was the first particle accelerator. They used it to bombard lithium, artificially transforming it into helium. The production of the helium nuclei was confirmed by observing their tracks in a cloud chamber. They then worked on the artificial disintegration of other elements, such as boron. Cockcroft was born in Todmorden, W Yorkshire, and studied at Manchester and Cambridge, where he took up research work under Ernest Rutherford at the Cavendish Laboratory. Having been in charge of the construction of the first nuclear-power station in Canada during World War II, he returned to the UK to be director of Harwell Atomic Energy Research Establishment 1946-58, and in 1959 became first Master of Churchill College, Cambridge.