Enrico Fermi (1901 - 1954)Fermi and Pauli postulated that a neutrino () would be emitted during Beta Decay.
Notable Accomplishments
The Nobel Prize in Physics 1938 - "for his demonstrations of the existence of new radioactive elements produced by neutron irradiation, and for his related discovery of nuclear reactions brought about by slow neutrons."
Stagg Field Reactor
Chicago Pile-1, the first nuclear reactor to achieve a self-sustaining chain reaction