The Nobel Prize in Physics 1951
John Cockcroft, Ernest T.S. Walton
Ernest Thomas Sinton Walton
Born: 6 October 1903, Dungarvan, Ireland
Died: 25 June 1995, Belfast, Northern Ireland
Affiliation at the time of the award: Trinity College, Dublin, Ireland
Prize motivation: "for their pioneer work on the transmutation of atomic nuclei by artificially accelerated atomic particles"
Field: accelerator physics, nuclear physics
Prize share: 1/2
Ernest Rutherford used alpha particles from radioactive elements to study nuclear reactions and managed to convert nitrogen to oxygen. However, only very few reactions could be achieved with alpha particles from radioactive elements. Ernest Walton and John Cockcroft developed a device, an accelerator, to make more penetrating radiation. Using an electric field, protons were accelerated to high velocities. In 1932 they bombarded lithium with protons and the lithium nucleus broke-up and two alpha particles were produced.