James Chadwick

Sir James Chadwick was a British physicist, born October 20, 1891 in Cheshire, England and died July 24, 1974 in Cambridge, whose discovery of the neutron made it possible to understand how a nuclear chain reaction, and so nuclear energy, could work at all. After graduating from the University of Manchester with first class honours in 1911 and earning a Cambridge doctorate in 1921, he discovered the neutron in February 1932 after roughly two weeks of experiments, announcing it in a letter to Nature titled Possible Existence of a Neutron and publishing full findings that May in the Proceedings of the Royal Society; the discovery earned him the 1935 Nobel Prize in Physics. In 1941 he wrote the final draft of the MAUD Report assessing the feasibility of an atomic bomb, which after reaching President Franklin Roosevelt that October helped prompt the American atomic bomb effort, and he went on to head the British mission to the Manhattan Project, working closely with its director Leslie Groves and gaining access to nearly every American research site involved. He held the Lyon Jones chair at the University of Liverpool from 1935, was knighted in 1945, and served as Master of Gonville and Caius College, Cambridge from 1948 to 1959.