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, England (near Cambridge), 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.
List of scientists
The following German scientists were captured and detained during Operation Epsilon:
Farm Hall transcripts
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:Diebner: "I wonder whether there are microphones installed here?" Heisenberg: "Microphones installed? (laughing) Oh no, they're not as cute as all that. I don't think they know the real Gestapo methods; they're a bit old fashioned in that respect."
Most historians see no reason to believe that he was not being genuine, and the attitude of Heisenberg and the other scientists over all the months and especially their reaction to the shattering news of the bomb explosion seems to have been so genuine that it seems unlikely to have been staged.
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."
Some of the scientists had almost nothing to do with the nuclear project. Otto Hahn, for example, had (with his assistant Fritz Strassmann) discovered nuclear fission in December 1938, but otherwise had no participation. Max von Laue was, like Hahn, an ardent anti-Nazi and had not done any work relating to wartime physics. In the transcripts, Otto Hahn contemplates suicide after learning of the bombing of Hiroshima, believing himself personally responsible for the many Japanese victims, while less than two weeks after the announcement Heisenberg had figured out the process by which the bomb was built.
The transcripts were originally sent as reports to British military officers, and were then forwarded to the U.S. War Department, where they eventually made it to General Leslie Groves of the Manhattan Project, as part of Operation Alsos. In February 1992 they were declassified and published.
The events at Farm Hall were dramatised on BBC Radio 4 on 15 June 2010, in "Nuclear Reactions", written by Adam Ganz, son of one of the interpreters, Peter Ganz.
A play "Operation Epsilon" by Alan Brody, largely based on the transcripts, opened on March 7, 2013 in Cambridge, Massachusetts. A staged reading of the play "Farm Hall" by David C. Cassidy, was presented on February 15, 2013, in the Science & the Arts program at The Graduate Center of the City University of New York. A second reading was performed on March 20, 2013, at the annual March meeting of The American Physical Society in Baltimore, Maryland.