Near the end of World War II, the principal Allied war powers each made plans for exploitation of German science. In light of the implications of nuclear weapons, German nuclear fission and related technologies were singled out for special attention. In addition to exploitation, denial of these technologies, their personnel, and related materials to rival allies was a driving force of their efforts. This typically meant getting to these resources first, which to some extent put the Soviets at a disadvantage in some geographic locations easily reached by the Western Allies, even if the area was allotted to the Soviet zone of occupation at the
Potsdam Conference. At times, all parties were heavy-handed in their pursuit and denial to others. The best known US effort was
Operation Paperclip, a broad dragnet that encompassed a wide range of advanced fields, including jet and rocket propulsion, nuclear physics, and other developments with military applications such as infrared technology. Operations directed specifically towards German nuclear fission were
Operation Alsos and
Operation Epsilon, the latter being done in collaboration with the British. In lieu of the codename for the Soviet operation, it is referred to by the historian Oleynikov as the
Russian "Alsos".
American and British Berlin had been a location of many German scientific research facilities. To limit casualties and loss of equipment, many of these facilities were dispersed to other locations in the later years of the war.
Operation Big Unfortunately for the Soviets, the
Kaiser-Wilhelm-Institut für Physik (KWIP, Kaiser Wilhelm Institute for Physics) had mostly been moved in 1943 and 1944 to
Hechingen and its neighboring town of
Haigerloch, on the edge of the
Black Forest, which eventually became the French occupation zone. This move allowed the Americans to take into custody a large number of German scientists associated with nuclear research. The only section of the institute which remained in Berlin was the low-temperature physics section, headed by , who was in charge of the experimental uranium pile. American Alsos teams carrying out Operation Big raced through
Baden-Württemberg near the war's end in 1945, uncovering, collecting, and selectively destroying
Uranverein elements, including capturing a prototype reactor at Haigerloch and records, heavy water, and uranium ingots at Tailfingen (today part of
Albstadt). These were all shipped to the US for study and utilization in the US atomic program. Although many of these materials remain unaccounted for, the
National Museum of Nuclear Science & History displayed a cube of uranium attained from this mission from March 2020.
Operation Epsilon, and Farm Hall A major goal of the
Operation Alsos effort in Germany was the location, capture, and interrogation of German nuclear scientists. This involved some significant effort as many of them had become scattered during the chaotic last weeks of the war in Europe. Ultimately, nine of the prominent German scientists who published reports in
Kernphysikalische Forschungsberichte as members of the
Uranverein were picked up by the Alsos team and incarcerated in England as part of what was called
Operation Epsilon:
Erich Bagge,
Kurt Diebner,
Walther Gerlach,
Otto Hahn,
Paul Harteck,
Werner Heisenberg,
Horst Korsching,
Carl Friedrich von Weizsäcker, and
Karl Wirtz. Also incarcerated was
Max von Laue, although he had nothing to do with the nuclear weapon project.
Goudsmit, the chief scientific advisor to Operation Alsos, thought von Laue might be beneficial to the post-war rebuilding of Germany and would benefit from the high level contacts he would have in England. The ten scientists were secretly relocated and kept confined and incommunicado with the broader world in
Farm Hall, a manor house in
Godmanchester. The legal authority for this, the legal status of the prisoners, and the ultimate intentions of the British were unclear to all involved, to the great discomfort of the scientists. The manor house was wired with
covert listening devices, and conversations between the German scientists were monitored and translated into English. It is unclear whether the scientists were aware, or whether they suspected, that they were being monitored. Prior to the announcement of Hiroshima, the German scientists, though worried about the future, expressed confidence in their value to the Allies on the basis of their advanced knowledge of nuclear matters. The British then told the scientists that the
BBC had announced the use of the atomic bomb after the attack on Hiroshima. Reactions from the Germans varied; Hahn expressed guilt for his role in the discovery of nuclear fission, while many others, including Heisenberg, expressed incredulity at the report ("I don’t believe a word of the whole thing"). Later that evening, the scientists were allowed to listen to a longer BBC announcement, which invited further debate. Throughout all of this, Heisenberg made arguments that it would take very large amounts of enriched uranium ("about a ton") to make such a weapon. In justifying his reasoning, he gave a brief explanation of how one would calculate the critical mass for an atomic bomb which contained serious errors. The transcripts were declassified in 1992, and this particular section of discussion was subjected to expert scrutiny. Two scientists on the Manhattan Project,
Edward Teller and
Hans Bethe, concluded after reading the transcripts that Heisenberg had never done the calculation before. Heisenberg himself, in the transcript, said that, "quite honestly I have never worked it [the critical mass calculation for an atomic bomb] out as I never believed one could get pure [uranium-]235." A week after the bombing, Heisenberg had given a more formal lecture to his colleagues on the physics of the atomic bomb, which corrected many of his early mistakes and indicated a much smaller critical mass. Historians have cited Heisenberg's error as evidence of the degree to which his role in the project had been confined almost entirely to reactors, as the original equation is much more similar to how a reactor would work than to an atomic bomb. At Farm Hall, the German scientists discussed why Germany did not create an atomic bomb, and the United States and United Kingdom did. The transcripts reveal them developing what has been called the
Lesart ("version"). The
Lesart argued that the German scientists
chose not to build a bomb for Hitler, either by dragging their feet, being insufficiently enthusiastic, or, in some versions, active sabotage. The
Lesart both offers up an explanation for their "failure" and also elevates their moral authority above the Allied scientists, despite the fact that they worked for the Nazis. After the war, von Weizsäcker and Heisenberg and several others spread this version of the story to journalists and historians, like
Robert Jungk, who reprinted and amplified it uncritically in the 1950s. Already by that time, the historical accuracy of the
Lesart had been challenged forcefully by von Laue (who coined the term
Lesart) and nowadays most professional historians of science with knowledge of the subject do not believe that the
Lesart is true. As the historian and physicist
Jeremy Bernstein put it in an annotated edition of the Farm Hall transcripts: The
Lesart has been perpetuated in many popular accounts of the German nuclear program, notably in
Michael Frayn's 1998 play
Copenhagen, which itself was based heavily on the
Lesart-endorsing work of popular history, ''Heisenberg's War'' (1993), by the journalist
Thomas Powers.
Oranienburg plant With the interest of the
Heereswaffenamt (HWA, Army Ordnance Office),
Nikolaus Riehl, and his colleague
Günter Wirths, set up an industrial-scale production of high-purity uranium oxide at the
Auergesellschaft plant in
Oranienburg. Adding to the capabilities in the final stages of metallic uranium production were the strengths of the Degussa corporation's capabilities in metals production. The Oranienburg plant provided the uranium sheets and cubes for the
Uranmaschine experiments conducted at the KWIP and the
Versuchsstelle (testing station) of the
Heereswaffenamt (Army Ordnance Office) in Gottow. The G-1 experiment performed at the HWA testing station, under the direction of
Kurt Diebner, had lattices of 6,800 uranium oxide cubes (about 25 tons), in the nuclear moderator paraffin. Work of the American Operation Alsos teams, in November 1944, uncovered leads which took them to a company in Paris that handled rare earths and had been taken over by the
Auergesellschaft. This, combined with information gathered in the same month through an Alsos team in
Strasbourg, confirmed that the Oranienburg plant was involved in the production of uranium and thorium metals. Since the plant was to be in the future Soviet zone of occupation and the Red Army's troops would get there before the Western Allies, General
Leslie Groves, commander of the
Manhattan Project, recommended to General
George Marshall that the plant be destroyed by aerial bombardment, in order to deny its uranium production equipment to the Soviets. On 15 March 1945, 612
B-17 Flying Fortress bombers of the
Eighth Air Force dropped 1,506 tons of high-explosive and 178 tons of incendiary bombs on the plant. Riehl visited the site with the Soviets and said that the facility was mostly destroyed. Riehl also recalled long after the war that the Soviets knew precisely why the Americans had bombed the facility—the attack had been directed at them rather than the Germans.
French From 1941 to 1947,
Fritz Bopp was a staff scientist at the KWIP, and worked with the
Uranverein. In 1944, he went with most of the KWIP staff when they were evacuated to
Hechingen in Southern Germany due to air raids on Berlin, and became the institute's deputy director. When the
American Alsos Mission evacuated Hechingen and
Haigerloch, near the end of World War II, French armed forces occupied Hechingen. Bopp did not get along with them and described the initial French policy objectives towards the KWIP as exploitation, forced evacuation to France, and seizure of documents and equipment. The French occupation policy was not qualitatively different from that of the American and Soviet occupation forces, it was just carried out on a smaller scale. In order to put pressure on Bopp to evacuate the KWIP to France, the French Naval Commission imprisoned him for five days and threatened him with further imprisonment if he did not cooperate in the evacuation. During his imprisonment, the
spectroscopist , who had a better relationship with the French, persuaded the French to appoint him as deputy director of the KWIP. This incident caused tension between the physicists and spectroscopists at the KWIP and within its umbrella organization the
Kaiser-Wilhelm Gesellschaft (Kaiser Wilhelm Society).
Soviet At the close of World War II, the Soviet Union had special search teams operating in Austria and Germany, especially in Berlin, to identify and obtain equipment, material, intellectual property, and personnel useful to the
Soviet atomic bomb project. The exploitation teams were under the
Soviet Alsos and they were headed by
Lavrentiy Beria's deputy,
Colonel General A. P. Zavenyagin. These teams were composed of scientific staff members, in
NKVD officer's uniforms, from the bomb project's only laboratory, Laboratory No. 2, in Moscow, and included
Yulij Borisovich Khariton,
Isaak Konstantinovich Kikoin, and
Lev Andreevich Artsimovich.
Georgij Nikolaevich Flerov had arrived earlier, although Kikoin did not recall a vanguard group. Targets on the top of their list were the
Kaiser-Wilhelm Institut für Physik (KWIP,
Kaiser Wilhelm Institute for Physics), the Frederick William University (today, the
University of Berlin), and the
Technische Hochschule in Charlottenburg (now
Technische Universität Berlin). German physicists who worked on the
Uranverein and were sent to the
Soviet Union to work on the
Soviet atomic bomb project included: ,
Robert Döpel,
Walter Herrmann,
Heinz Pose,
Ernst Rexer,
Nikolaus Riehl, and
Karl Zimmer.
Günter Wirths, while not a member of the
Uranverein, worked for Riehl at the
Auergesellschaft on reactor-grade uranium production and was also sent to the Soviet Union. Zimmer's path to work on the Soviet atomic bomb project was through a prisoner of war camp in
Krasnogorsk, as was that of his colleagues
Hans-Joachim Born and
Alexander Catsch from the
Kaiser-Wilhelm Institut für Hirnforschung (KWIH,
Kaiser Wilhelm Institute for Brain Research, today the
Max-Planck-Institut für Hirnforschung), who worked there for
N. V. Timofeev-Resovskij, director of the
Abteilung für Experimentelle Genetik (Department of Experimental Genetics). All four eventually worked for Riehl in the Soviet Union at
Laboratory B.
Von Ardenne, who had worked on isotope separation for the
Reichspostministerium (Reich Postal Ministry), was also sent to the Soviet Union to work on their atomic bomb project, along with
Gustav Hertz, Nobel laureate and director of Research Laboratory II at
Siemens,
Peter Adolf Thiessen, director of the
Kaiser-Wilhelm Institut für physikalische Chemie und Elektrochemie (KWIPC, Kaiser Wilhelm Institute for Chemistry and Electrochemistry, today the
Fritz Haber Institute of the Max-Planck Society), and
Max Volmer, director of the Physical Chemistry Institute at the
Technische Hochschule in Charlottenburg (now
Technische Universität Berlin), who all had made a pact that whoever first made contact with the Soviets would speak for the rest. Before the end of World War II, Thiessen, a member of the
Nazi Party, had Communist contacts. On 27 April 1945, Thiessen arrived at von Ardenne's institute in an armored vehicle with a major of the Soviet Army, who was also a leading Soviet chemist, and they issued Ardenne a protective letter (
Schutzbrief). ==Comparison to the Manhattan Project==