Dunning, John Ray
Dunning, John Ray (1907-1975), an American physicist, did research work that was important in developing the atomic bomb. With the cooperation of Alfred O. Nier, who separated small quantities of the isotopes (forms) of uranium known as U-235 and U-238 from each other, Dunning, E. T. Booth, and A. V. Grosse proved that slowly moving neutrons can cause U-235