This endeavor, known as the Uranverein, occupied Heisenberg throughout the war. The project was not successful, but the cause of its failure is still a matter of debate. Heisenberg claimed after the war that he had tried to impede the project as best he could to deny the Nazis an atomic bomb, a claim that some scholars contest. A principal cause of the project's failure was a lack of resources. The dearth of material and the resulting slow progress in research led to a mid-1942 report to Adolf Hitler that projected the development of a German atomic bomb as being several years in the future. Hitler, convinced that Germany would not be able to deploy such a weapon during World War II, consequently took little interest in the project.
Following the defeat of Germany, Heisenberg was among those German physicists briefly imprisoned in Britain by the Allies. In 1946 he was allowed to return to Germany and reorganized at Göttingen the Institute for Physics, later known as the Max Planck Institute for Physics. Heisenberg remained active in the field of physics in subsequent years. He died in Munich on 1 February 1976.
Eric W. Osborne
Cassidy, David Charles. The Life and Science of Werner Heisenberg. New York: W. H. Freeman, 1992.; Powers, Thomas. Heisenberg's War: The Secret History of the German Bomb. Cambridge, MA: Da Capo Press, 2000.