Ernest Wollan

Ernest Omar Wollan (November 6, 1902 – March 11, 1984) was an American physicist who made major contributions in the fields of neutron scattering and health physics.

Wollan was a native of Glenwood, Minnesota. After earning a bachelor's degree at Concordia College in 1923, he undertook graduate study at the University of Chicago, where he investigated X-ray scattering under Arthur Compton and received a Ph.D. in 1929. Over the next several years, he taught physics at North Dakota State College and Washington University, spent a year in Zurich as a National Research Council fellow conducting research on cosmic rays, and worked with the Chicago Tumor Institute on its medical use of a radium source.

In January 1942, Wollan joined the University of Chicago Metallurgical Laboratory at the invitation of Compton and Enrico Fermi. As a member of the Manhattan Project research team, he focused on measuring radiation exposure, for which he developed the film badge dosimeter. He was one of the 50 scientists present on December 2, 1942, when the first man-made self-sustaining nuclear chain reaction was achieved in the Chicago Pile experiment. He was also on the scene in Oak Ridge on November 4, 1943, when the first continuously operating reactor, the Clinton Pile, later known as the X-10 Graphite Reactor, first went critical.

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