John Cockcroft

John Douglas Cockcroft was a British experimental physicist. Working with Ernest Walton at Cambridge, he built an apparatus, later known as the Cockcroft-Walton generator, that used artificially accelerated protons to split lithium nuclei, achieving the transmutation of atomic nuclei by means entirely under human control. He shared the 1951 Nobel Prize in Physics with Walton for this pioneer work on the transmutation of atomic nuclei by artificially accelerated atomic particles.