 Walter Zinn

Walter Henry Zinn (December 10, 1906 – February 14, 2000) was an American nuclear physicist who was the first director of the Argonne National Laboratory from 1946 to 1956.He worked at the Manhattan Project's Metallurgical Laboratory during World War II, and supervised the construction of Chicago Pile-1, the world's first nuclear reactor, which went critical on December 2, 1942, at the University of Chicago.