Theodore A. Welton was born in Saratoga Springs , New York . He was educated at the Massachusetts Institute of Technology where he received at B.S. degree in 1939 . He received his Ph.D. from the University of Illinois in 1944 . He worked at Los Alamos National Laboratory on diffusion problems during the Manhattan Project and was present at the Trinity Test . After World War II he taught at MIT and the University of Pennsylvania . In 1950 he went to work at Oak Ridge National Laboratory in the Theoretical Physics Division , and in the following year with Herbert Callen he published the landmark Fluctuation-dissipation theorem , showing that the explanations of Brownian motion and Johnson noise are specific examples of the more general theorem . Over the course of his career he contributed to the development of nuclear reactors , and worked on particle physics , and electron microscopy . He received a Humboldt Prize for his work in physics
Trinity Test
Trinity (nuclear test)
Theodore A. Welton