William Draper Harkins

Harkins correctly predicted the existence of the neutron in 1920 (as a proton–electron complex) and was the first to use the word neutron in connection with the atomic nucleus. The neutron was detected experimentally by James Chadwick in 1932. In the beginning of the 1930s, Harkins constructed the second ever cyclotron with fellow University of Chicago scientist Robert James Moon, improving greatly on the design of the previous one. Among other University of Chicago scientists who made use of this cyclotron was Enrico Fermi, who performed neutron transport experiments. Since 1978, the magnet yoke of the cyclotron Harkins built has been on display at Fermilab.thumb The magnet yoke from the cyclotron built in 1935 by Professor William D. Harkins and colleagues at the University of Chicago was moved in 1978 to Fermi National Accelerator Laboratory near Batavia, Illinois, where it is on display. Photo: William S. Higgins Harkins was elected to the United States National Academy of Sciences in 1921 and the American Philosophical Society in 1925.

Among his students were Robert Mulliken, Lyle Benjamin Borst, Calvin Souther Fuller, Martin Kamen, Henry W. Newson, Samuel Allison, and Robert James Moon.

Harkins died in Chicago. He is buried at Oak Woods Cemetery.