Enrico Fermi, laboratory notebook, 1941. In the months before coming to Chicago in the spring of 1942, Fermi and his team of physicists at Columbia University worked on a preliminary design for an atomic pile. With Leo Szilard, Walter Zinn, Herbert Anderson, and other colleagues, Fermi devised a lattice structure of graphite and uranium oxide for an "exponential" pile and calculated the requirements for a self-sustaining chain reaction.