Used with
permission of Maiken Naylor, University at Buffalo, Buffalo, NY, USA,
http://ublib.buffalo.edu/libraries/units/sel/exhibits/stamps
Enrico Fermi (1901-1954) produced thermal neutrons by slowing them down in water, and then used them to start the first self- sustainig chain reaction in uranium, at the University of Chicago under the football stadium in 1942; it was the beginning of the nuclear age.