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, [1] 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. [2] 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: [3]
The participants of the Manhattan Project perceived themselves as being in a competition with the Germans, who had a head start due to the discovery of nuclear fission by Otto Hahn in Germany in late 1938.
In 1944, the ALSOS mission, under scientific leadership of Samuel Goudsmit, was tasked with closely following the Western Allied invading forces to locate and seize individuals, documents, and materials related to the German Atomic Bomb program. By November 1944, the evidence gathered was sufficient to convince Goudsmit that there was no German Atomic Bomb under development. Despite this, many individuals, particularly in America, remained skeptical.
The mission continued with a similar objective, primarily for intelligence purposes. Goudsmit hand-picked ten individuals who were apprehended, mostly in Hechingen, by a joint Anglo-American raiding party led by Colonel Boris Pash, the key military figure of ALSOS. [4] Hechingen, located on the eastern edge of the Black Forest, was where the majority of the Kaiser Wilhelm Institut für Physik, including an incomplete nuclear reactor pile that had been moved after being bombed out in Berlin.
R. V. Jones proposed that Farm Hall in England, owned by the Secret Service, would be suitable to accommodate the captured individuals. [5] He also recommended installing microphones there before their arrival. This practice had become standard with high-ranking prisoners of war since it had been observed that their private conversations could be more revealing than formal interrogations.
The scientists captured in Germany by the Alsos Mission were flown to England. Harteck said in a 1967 interview that some scientists had not adjusted to losing their German elite status. When Max von Laue was told they were to fly to England the next day, he said, "Impossible .... tomorrow is my colloquium .... Couldn’t you have the airplane come some other time?". Walther Gerlach expected respect for the "plenipotentiary for nuclear physics" in Germany; he was shocked when he asked for a glass of water and was told by the guard to "look for an empty can in the trash barrel". Harteck joked with the British officer when he saw the plane taking them to England that if an "accident" was planned they would have used an older plane. [6]
Farm Hall, a country house in Godmanchester, Huntingdonshire (now in Cambridgeshire), had been used by M.I.6 and S.O.E for agents who were to be flown into occupied Europe from RAF Tempsford but was vacant. R V Jones suggested to Stewart Menzies that German nuclear physicists then held in France at an American internment camp known as "Dustbin" (partly because he was told that an American general had said that the best way of dealing with the post-war nuclear physics problem in Germany was to shoot all their nuclear physicists). He also recommended to Menzies, the head of M.I.6, that the house be fitted with microphones to gauge the physicists' reactions to Allied progress with the dropping of the bomb. [7]
On July 6, the microphones picked up the following conversation between Werner Heisenberg and Kurt Diebner, [8] both of whom had worked on the German nuclear project and had been seized as part of the Allied Alsos Mission, Diebner in Berlin [9] and Heisenberg in Urfeld,
Diebner: I wonder whether there are microphones installed here?
All of the scientists expressed shock when informed of the atomic bombing of Hiroshima on August 6, 1945. Some first doubted that the report was genuine. They were told initially of an official announcement that an "atomic bomb" had been dropped on Hiroshima, with no mention of uranium or nuclear fission. Harteck said that he would have understood the words "uranium" or "nuclear (fission) bomb", but he had worked with atomic hydrogen and atomic oxygen and thought that American scientists might have succeeded in stabilising a high concentration of (separate) atoms; such a bomb would have had a tenfold increase over a conventional bomb. [10]
The scientists then contemplated how the American bomb was made and why Germany did not produce one. 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; in fact, it is estimated that they would have never been able to produce the amount they needed in the four years they wanted to create an atomic bomb. [11] Heisenberg specifically thought that the amount of Uranium 235 needed at critical mass was about a thousand times more than what would make an atomic bomb explode. [12]
Some of the scientists indicated that they were happy that they had not been able to build a nuclear bomb for Adolf Hitler, while others more sympathetic to the Nazi party (Diebner and Gerlach) 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." [13]
All were physicists except for Hahn and Harteck, who were chemists, and all except Max von Laue had participated in the German nuclear project. During his incarceration in Farm Hall, Hahn was awarded the 1944 Nobel Prize for Chemistry "for his discovery of the fission of heavy nuclei". [14]
A group of eight people, including Peter Ganz, led by Major T. H. Rittner, was responsible for eavesdropping, recording, copying and translating. Only relevant technical or political information, about ten percent of all words heard, was recorded, transcribed and translated. The recordings were made with six to eight machines on shellac-coated metal discs. After the selective transcriptions had been made, the discs and recordings were destroyed. The transcripts were sent as reports to London and the American consulate, and were then forwarded to General Leslie Groves of the Manhattan Project [3] in 24 reports, over 250 pages.
In February 1992 the transcripts were declassified and published.
On 24 February 1992 the BBC broadcast a Horizon drama-documentary entitled Hitler's Bomb based on the events at Farm Hall and examining the reasons for the failure of the German nuclear weapons program. The documentary was produced by David Sington with dramatic reconstructions written by Nick Perry.
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 titled Operation Epsilon by Alan Brody, based on the original transcripts, received its first reading as part of the Catalyst Collaborative at MIT (Boston) in 2008, followed by a workshop reading in New York in 2010, directed by Andy Sandberg and produced by Ellen Berman. Brody and Sandberg subsequently developed the play in a 2011 workshop at the Asolo Repertory Theatre (Sarasota, Florida). Prior to its world premiere production in early 2013 with the Nora Theatre Company at Central Square Theater (Cambridge, Massachusetts).
A further adaptation, Farm Hall by Katherine M. Moar, was performed as a staged reading at the Theatre Royal, Bath on 21 September 2019. It was later revived as a full production directed by Stephen Unwin at Jermyn Street Theatre and the Theatre Royal, Bath in 2023, and as a tour of the same production at Cambridge Arts Theatre, Perth Theatre, Yvonne Arnaud Theatre, Oxford Playhouse and Richmond Theatre later in 2023. Farm Hall transferred to the Theatre Royal Haymarket in London with the original cast for a short run in August 2024. [15]
Werner Karl Heisenberg was a German theoretical physicist, one of the main pioneers of the theory of quantum mechanics, and a principal scientist in the Nazi nuclear weapons program during World War II. He published his Umdeutung paper in 1925, a major reinterpretation of old quantum theory. In the subsequent series of papers with Max Born and Pascual Jordan, during the same year, his matrix formulation of quantum mechanics was substantially elaborated. He is known for the uncertainty principle, which he published in 1927. Heisenberg was awarded the 1932 Nobel Prize in Physics "for the creation of quantum mechanics".
Otto Hahn was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner discovered radioactive isotopes of radium, thorium, protactinium and uranium. He also discovered the phenomena of atomic recoil and nuclear isomerism, and pioneered rubidium–strontium dating. In 1938, Hahn, Meitner and Fritz Strassmann discovered nuclear fission, for which Hahn alone, was awarded the 1944 Nobel Prize for Chemistry. Nuclear fission was the basis for nuclear reactors and nuclear weapons.
The Alsos Mission was an organized effort by a team of British and United States military, scientific, and intelligence personnel to discover enemy scientific developments during World War II. Its chief focus to investigate the progress that Nazi Germany was making in the area of nuclear technology, and to seize any German nuclear resources that would either be of use to the Manhattan Project or worth denying to the Soviet Union. It also investigated German chemical and biological weapon development and the means to deliver them, and any other advanced Axis technology it was able to get information about in the course of the other investigations.
Walther Gerlach was a German physicist who co-discovered, through laboratory experiment, spin quantization in a magnetic field, the Stern–Gerlach effect. The experiment was conceived by Otto Stern in 1921 and successfully conducted first by Gerlach in early 1922.
Erich Rudolf Bagge was a German scientist. Bagge, a student of Werner Heisenberg for his doctorate and Habilitation, was engaged in German Atomic Energy research and the German nuclear energy project during the Second World War. He worked as an Assistant at the Kaiser-Wilhelm-Institut für Physik in Berlin. Bagge, who became associated professor at the University of Hamburg in 1948, was in particular involved in the usage of nuclear power for trading vessels, and he was one of the founders of the Society for the Usage of Nuclear Energy in Ship-Building and Seafare.
Carl Friedrich Freiherr von Weizsäcker was a German physicist and philosopher. He was the longest-living member of the team which performed nuclear research in Nazi Germany during the Second World War, under Werner Heisenberg's leadership. There is ongoing debate as to whether or not he and the other members of the team actively and willingly pursued the development of a nuclear bomb for Germany during this time.
Nazi Germany undertook several research programs relating to nuclear technology, including nuclear weapons and nuclear reactors, before and during World War II. These were variously called Uranverein or Uranprojekt. The first effort started in April 1939, just months after the discovery of nuclear fission in Berlin in December 1938, but ended only a few months later, shortly ahead of the September 1939 German invasion of Poland, for which many notable German physicists were drafted into the Wehrmacht. A second effort under the administrative purview of the Wehrmacht's Heereswaffenamt began on September 1, 1939, the day of the invasion of Poland. The program eventually expanded into three main efforts: Uranmaschine development, uranium and heavy water production, and uranium isotope separation. Eventually, the German military determined that nuclear fission would not contribute significantly to the war, and in January 1942 the Heereswaffenamt turned the program over to the Reich Research Council while continuing to fund the activity.
Friedrich Wilhelm Strassmann was a German chemist who, with Otto Hahn in December 1938, identified the element barium as a product of the bombardment of uranium with neutrons. Their observation was the key piece of evidence necessary to identify the previously unknown phenomenon of nuclear fission, as was subsequently recognized and published by Lise Meitner and Otto Frisch. In their second publication on nuclear fission in February 1939, Strassmann and Hahn predicted the existence and liberation of additional neutrons during the fission process, opening up the possibility of a nuclear chain reaction.
Kurt Diebner was a German nuclear physicist who is well known for directing and administering parts of the German nuclear weapons program, a secretive program aiming to build nuclear weapons for Nazi Germany during World War II. He was appointed the project's administrative director after Adolf Hitler authorized it.
Erich Schumann was a German physicist who specialized in acoustics and explosives, and had a penchant for music. He was a general officer in the army and a professor at the University of Berlin and the Technische Hochschule Berlin. When Adolf Hitler came to power he joined the Nazi Party. During World War II, his positions in the Army Ordnance Office and the Army High Command made him one of the most powerful and influential physicists in Germany. He ran the German nuclear energy program from 1939 to 1942, when the army relinquished control to the Reich Research Council. His role in the project was obfuscated after the war by the German physics community's defense of its conduct during the war. The publication of his book on the military's role in the project was not allowed by the British occupation authorities. He was director of the Helmholtz Institute of Sound Psychology and Medical Acoustics.
Karl Eugen Julius Wirtz was a German nuclear physicist, born in Cologne. He was arrested by the allied British and American Armed Forces and incarcerated at Farm Hall for six months in 1945 under Operation Epsilon.
Horst Korsching was a German physicist. He was arrested by the allied British and American Armed Forces and incarcerated at Farm Hall for six months in 1945 under Operation Epsilon.
Paul Karl Maria Harteck was an Austrian physical chemist. In 1945 under Operation Epsilon in "the big sweep" throughout Germany, Harteck was arrested by the allied British and American Armed Forces for suspicion of aiding the Nazis in their nuclear weapons program and he was incarcerated at Farm Hall, an English house fitted with covert electronic listening devices, for six months.
Kernphysikalische Forschungsberichte was an internal publication of the German Uranverein, which was initiated under the Heereswaffenamt in 1939; in 1942, supervision of the Uranverein was turned over to the Reichsforschungsrat under the Reichserziehungsministerium. Reports in this publication were classified Top Secret, they had very limited distribution, and the authors were not allowed to keep copies. The reports were confiscated under the Allied Operation Alsos and sent to the United States Atomic Energy Commission for evaluation. In 1971, the reports were declassified and returned to Germany. Many of the reports are available at the Karlsruhe Nuclear Research Center and the Niels Bohr Library of the American Institute of Physics. Many of them are reprinted and transcribed in the book "Collected Works / Gesammelte Werke" listed below which is available in most libraries. There are reports numbered G-1 to G-395.
The industrial firm Auergesellschaft was founded in 1892 with headquarters in Berlin. Up to the end of World War II, Auergesellschaft had manufacturing and research activities in the areas of gas mantles, luminescence, rare earths, radioactivity, and uranium and thorium compounds. In 1934, the corporation was acquired by the German corporation Degussa. In 1939, their Oranienburg plant began the development of industrial-scale, high-purity uranium oxide production. Special Soviet search teams, at the close of World War II, sent Auergesellschaft equipment, material, and staff to the Soviet Union for use in their nuclear weapon project. In 1958 Auergesellschaft merged with the Mine Safety Appliances Corporation, a multinational US corporation. Auergesellschaft became a limited corporation in 1960.
Robert Abraham Esau was a German physicist.
Wilhelm Hanle was a German experimental physicist. He is known for the Hanle effect. During World War II, he made contributions to the German nuclear energy project, also known as the Uranium Club. From 1941 until emeritus status in 1969, he was an ordinarius professor of experimental physics and held the chair of physics at the University of Giessen.
Gerhard Hoffmann was a German nuclear physicist. During World War II, he contributed to the German nuclear energy project, also known as the Uranium Club.
Klaus Paul Alfred Clusius was a German physical chemist from Breslau (Wrocław), Silesia. During World War II, he worked on the German nuclear energy project, also known as the Uranium Club; he worked on isotope separation techniques and heavy water production. After the war, he was a professor of physical chemistry at the University of Zurich. He died in Zurich.
Wilhelm Groth was a German physical chemist. During World War II, he worked on the German nuclear energy project, also known as the Uranium Club; his main activity was the development of centrifuges for the enrichment of uranium. After the war, he was a professor of physical chemistry at the University of Hamburg. In 1950, he became director of the Institute of Physical Chemistry at the University of Bonn. He was a principal in the 1956 shipment of three centrifuges for uranium enrichment to Brazil.