Farm Hall

Operation Epsilon was the codename of a program in which Allied forces near the end of World War II detained ten German scientists who were thought to have worked on Nazi Germany's nuclear program. The scientists were captured between May 1 and June 30, 1945, as part of the Allied Alsos Mission, mainly as part of its Operation Big sweep through southwestern Germany.

They were interned at Farm Hall, a bugged house in Godmanchester, near Cambridge, England, from July 3, 1945 to January 3, 1946. The primary goal of the program was to determine how close Nazi Germany had been to constructing an atomic bomb by listening to their conversations.

The following German scientists were captured and detained during Operation Epsilon:

The results of the transcripts were inconclusive. On July 6, the microphones picked up the following conversation between Werner Heisenberg and Kurt Diebner, both of whom had worked on the German nuclear project and had been seized as part of the Allied Alsos Mission, Diebner in Berlin and Heisenberg in Urfeld:

All of the scientists expressed shock when informed of the atomic bombing of Hiroshima on August 6, 1945. The transcripts seem to indicate that the physicists, in particular Heisenberg, had either overestimated the amount of enriched uranium that an atomic bomb would require or consciously overstated it, and that the German project was at best in a very early, theoretical stage of thinking about how atomic bombs would work. After first puzzling over whether or not the report was genuine, the scientists then contemplated how the bomb was made and why Germany was not able to produce one. Some of the scientists indicated that they were happy that they had not been able to build a nuclear bomb for Adolf Hitler, while some of the others, more sympathetic to the Nazi party, were dismayed at having failed. Otto Hahn, one of those who were grateful that Germany had not built a bomb, chided those who had worked on the German project, saying "If the Americans have a uranium bomb then you're all second-raters."

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