John Cockcroft and George Gamow, c 1930.
© Science Museum / Science & Society Picture Library
Cockroft (1897-1967) (left), and Gamow (1904-1968) independently worked on the disintegration of atomic nuclei. In 1928 Gamow showed how a particle could 'tunnel' through the barrier holding it to the nucleus. Cockcroft realised that the opposite proces might occur: an approaching proton could tunnel into the nucleus and cause disintegration. If only such low-energy protons were required, then building a machine, an accelerator, to provide such protons would become easier. He went on to do this.