Abstract: Relativity is Einstein^,s greatest scientific contribution to mankind, especially the popular mass-energy equation. However, physicists who proved Einstein^,s mass-energy equation by experiments were not known much until the Manhattan Project created the atomic bomb. In fact, as early as 1932, Walton from Ireland and Cockcroft from Britain successfully proved the equivalence of Einstein^,s mass-energy equation in the process of experiments of splitting atoms. Walton and Cockcroft shared the Hughes Medal in 1938 and the Nobel Prize in physics in 1951 for their great achievement of “disintegration of atomic nuclei by artificially accelerated atomic particles” in 1932. Comparing with Cockcroft^,s enthusiasm and extroversion, Walton was low-key, modest and introverted. His quiet personality perhaps have led many people to overlook his outstanding scientific achievements and social contributions. Taking the 90th anniversary of the verification of the mass-energy equation as an opportunity, this paper gives a detailed and comprehensive introduction to Walton who is a low-key but much-loved Irish physicist.

Key words: Walton, mass-energy equation, disintegration of atomic nuclei, Nobel Prize in physics