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John R. Dunning

PhysicistColumbia University

Manhattan Project VeteranScientist
John R. Dunning

John R. Dunning (1907-1975) was an American physicist. 

Dunning gained the reputation in his small community of Shelby, Nebraska as the town’s smartest kid. At the age of 10 he blew his home town’s electrical system while testing out his invention called the “electric arc.” By age 12, he had constructed his own radio. Dunning sailed through Shelby High School, earning high marks. He graduated in 1925 and attended Nebraska Wesleyan University, where he also excelled academically, and completed his B.A. by 1929.


Nuclear Research

In 1930, Dunning began his doctoral studies at Columbia University’s physics department. There, he began his career employed as a department assistant while also working towards his dissertation. He was awarded a fellowship from the university from 1932 to 1933, and he completed his Ph.D. the following year.

Dunning was appointed assistant professor at Columbia in 1935. He spent the 1935-36 academic year on a Cutting Traveling Fellowship, where he was funded to travel across Europe and work with some of the continent’s most eminent scholars in his field—scientists such as Heisenberg, Bohr, and Fermi. The neutron—its properties and potential applications—fascinated Dunning. He chose this sub-atomic particle as the central focus for much of his life’s research. When Columbia began construction on a university cyclotron (a machine which used electromagnetics to accelerate particles to near-speed of light levels), Dunning directed its development. This machine would become the location for several history-making experiments and discoveries in the field of nuclear physics. In 1938 he was promoted to the status of associate professor.

In 1939, Dunning led the American research team verifying fission of the uranium atom. During the Manhattan Project, Dunning led the day-to-day operations and research at the Substitute Alloy Materials Lab (SAM) at Columbia. SAM was an experimental group tasked with the development of a uranium enrichment process. Dunning conducted work on the gaseous diffusion method, and his research into the challenges of uranium enrichment played a crucial role in the Manhattan Project.



Dunning became Columbia’s Thayer Lindsley Professor of Applied Science in 1946. When the Atomic Energy Commission (AEC) and the Office of Naval Research partnered with Columbia University to construct a laboratory for postwar nuclear research (Nevis Laboratories), Dunning served as the project’s scientific director. Also in 1946, President Truman awarded Dunning the Medal of Merit—the highest honor the President bestows upon civilians.

Beginning in 1950, Dunning ended his direct involvement in scientific research when he accepted the deanship of Columbia’s school of engineering. He served on that post nineteen years, resigning in 1969. Dunning also served as a member on the board of directors of the Oak Ridge Institute of Nuclear Studies, as well as Columbia’s director of scientific research and chairman of the committee on government‐aided research.

Dr. John R. Dunning died on August 25, 1975.


For More Resources on Dunning:

John Dunning Memoir

NYT Dunning Obituary


John R. Dunning's Timeline
1907 Sep 24th Born in Shelby, Nebraska.
1929 Received a B.A. from Nebraska Wesleyan University.
1934 Received a Ph.D. in physics from Columbia University.
19351936 Traveled Europe meeting with prominent nuclear physicists.
1939 Led the American research team verifying fission of the uranium atom.
1940 Mar 2nd Made the first direct measurements of the enormous slow fission cross section of uranium-235.
1940 Nov Dunning and Harold Urey began investigating isotope separation techniques without U.S. government support.
1941 Nov 1st Dunning and Eugene Booth demonstrate the first measurable U-235 enrichment through gaseous diffusion.
19421945 Worked on the Manhattan Project as director of day-to-day operations and research at the Substitute Alloy Materials Lab (SAM) at Columbia University.
1946 Became full Professor of Physics at Columbia University.
1946 Received the Medal of Merit.
1948 Elected to the National Academy of Sciences.
1975 Aug 25th Died in Florida.

John Dunning

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