Werner Heisenberg

Werner Heisenberg was a German theoretical physicist, already known for the uncertainty principle, who led Nazi Germany's wartime nuclear energy research program, the Uranverein. Heisenberg's wartime research focused on building an experimental nuclear reactor using uranium and heavy water, but the German program never achieved a self-sustaining chain reaction before the war ended, a result generally attributed to resource shortages and reliance on heavy water as a neutron moderator rather than the purified graphite that worked for the American program. After the war Heisenberg was interned in Britain with other German scientists at Farm Hall, and he went on to lead West Germany's own postwar nuclear research effort as director of the Max Planck Institute for Physics.