John Ray Dunning (24.09.1907-25.08.1975) was an American physicist and a member of the National Academy of Sciences (1948). He was born in Shelby. He graduated from Wesleyan (1929) and Columbia (1934) universities and worked at the latter from 1929 (professor from 1946).
His research concerned nuclear physics and nuclear engineering and the application of electronics to nuclear physics. He was a pioneer of neutron research in the USA. He obtained the first indication that the neutron has a magnetic moment. He made the first measurements of the cross-section for the scattering of slow neutrons by protons, developed the first velocity selector for slow neutrons and discovered the strong interaction of thermal neutrons with cadmium. He was one of the first to prove experimentally that the uranium nucleus splits into two fragments, and he measured the energy of fission (1939). Together with A. Pir he developed the method of gaseous diffusion for separating uranium-235 and in 1940 separated it; he proved that uranium-235 is fissioned by slow neutrons.
The Pegram Medal (1964) and others.