John R. Dunning - Career

Career

After gaining his doctorate at Columbia, Dunning continued teaching and research there. He became assistant professor in 1935, associate professor in 1938, Thayer Lindsley Professor of Applied Science in 1946, and Dean of the School of Engineering and Applied Science in 1950. Appointment to the position of dean ended his active career in research at Columbia. By the time he stepped down as Dean in 1969, he had raised $50 million for the School.

After his promotion in 1935, Dunning became the central figure at Columbia on neutron research, and his activities complemented those of Enrico Fermi in Italy. Fermi and many of his colleagues came to Columbia to work with Dunning and his associates. In 1936, Dunning received a Traveling Fellowship, which he used to meet and discuss his neutron physics research with many eminent European nuclear physicists including Niels Bohr, James Chadwick, Fermi, Werner Heisenberg, and Ernest Rutherford.

Dunning closely followed the work of Ernest Lawrence on the cyclotron. Dunning wanted a more powerful neutron source and the cyclotron appeared as an attractive tool to achieve this end. During 1935 and 1936, he was able construct a cyclotron using many salvaged parts to reduce costs and funding from industrial and private donations.

In December 1938, the German chemists Otto Hahn and Fritz Strassmann sent a manuscript to Naturwissenschaften reporting they had detected the element barium after bombarding uranium with neutrons; simultaneously, they communicated these results to Lise Meitner. Meitner, and her nephew Otto Robert Frisch, correctly interpreted these results as being nuclear fission. Frisch confirmed this experimentally on 13 January 1939. In 1944, Hahn received the Nobel Prize for Chemistry for the discovery of nuclear fission. Some historians have documented the history of the discovery of nuclear fission and believe Meitner should have been awarded the Nobel Prize with Hahn.

Even before it was published, Meitner’s and Frisch’s interpretation of the work of Hahn and Strassmann crossed the Atlantic Ocean with Niels Bohr, who was to lecture at Princeton University. Isidor Isaac Rabi and Willis Lamb, two Columbia University physicists working at Princeton, heard the news and carried it back to Columbia. Rabi said he told Fermi; Fermi gave credit to Lamb. It was soon clear to a number of scientists at Columbia that they should try to detect the energy released in the nuclear fission of uranium from neutron bombardment. On 25 January 1939, Dunning was a member of the experimental team at Columbia University which conducted the first nuclear fission experiment in the United States, which was conducted in the basement of Pupin Hall; the other members of the team were Herbert L. Anderson, Eugene T. Booth, Enrico Fermi, G. Norris Glasoe, and Francis G. Slack.

During the Manhattan Project, Dunning conducted pioneering work at Columbia University on gaseous diffusion to separate uranium isotopes; others working on the project included Booth, Henry A. Boorse, Willard F. Libby, Alfred O. C. Nier, and Francis G. Slack. Due to the secrecy of this work, Dunning and three of his colleagues were awarded $300,000 each in lieu of patent royalties.