German nuclear program during World War II

German nuclear energy project
The German experimental nuclear pile at Haigerloch
Active	1939-1945 (the program was cancelled due to the Fall of Berlin)
Country	Nazi Germany
Allegiance	Nazi Germany
Branch	Army Ordnance Office Reich Research Council
Type	Nuclear Weapon Research
Nickname(s)	Uranverein
Engagements	World War II

The German nuclear energy project in Nazi Germany, informally known as the Uranverein (Uranium Club), began in April 1939, just months after the discovery of nuclear fission in January 1939. The first effort ended in months, but the second effort began under the auspices of the German Army Ordnance Office on the day World War II began, 1 September 1939. The program eventually expanded into the following main efforts: the Uranmaschine (nuclear reactor), uranium and heavy water production, and uranium isotope separation. The zenith of the effort came when it was realized that nuclear fission would not contribute significantly to ending the war. In January 1942, the Army Ordnance Office turned the program over to the Reich Research Council, but continued to fund the program. At this time, the program split up between nine major institutes where the directors dominated the research and set their own objectives. At that time, the number of scientists working on applied nuclear fission began to diminish, with many applying their talents to more pressing war-time demands.

The most influential people in the Uranverein were Kurt Diebner, Abraham Esau, Walther Gerlach, and Erich Schumann; Schumann was one of the most powerful and influential physicists in Germany. Diebner, throughout the life of the nuclear energy project, had more control over nuclear fission research than did Walther Bothe, Klaus Clusius, Otto Hahn, Paul Harteck, or Werner Heisenberg. Abraham Esau was appointed as Hermann Göring’s plenipotentiary for nuclear physics research in December 1942; Walther Gerlach succeeded him in December 1943.

Politicization of the German academia under the National Socialist regime had driven many physicists and mathematicians out of Germany as early as 1933. Those of Jewish heritage who did not leave were quickly purged from German institutions, further decimating the academia. The politicization and purges, along with the demands for armed manpower, in time would all but eliminate a generation of physicists.

At the end of the war, the Allied powers competed to obtain surviving components of the nuclear industry (personnel, facilities, and materiel), as they did with the V-2 program.

Discovery of nuclear fission

Main articles: History of physics, History of nuclear weapons, and World War II

In December 1938, the German chemists Otto Hahn and Fritz Strassmann sent a manuscript to Naturwissenschaften reporting they had detected the element barium after bombarding uranium with neutrons; simultaneously, they communicated these results to Lise Meitner, who had in July of that year fled to The Netherlands and then went to Sweden. Meitner, and her nephew Otto Robert Frisch, correctly interpreted these results as being nuclear fission. Frisch confirmed this experimentally on 13 January 1939.

1^st Uranverein

Paul Harteck was director of the physical chemistry department at the University of Hamburg and an advisor to the Heereswaffenamt (HWA, Army Ordnance Office). On 24 April 1939, along with his teaching assistant Wilhelm Groth, Harteck made contact with the Reichskriegsministerium (RKM, Reich Ministry of War) to alert them to the potential of military applications of nuclear chain reactions. Two days earlier, on 22 April 1939, after hearing a colloquium paper by Wilhelm Hanle on the use of uranium fission in a Uranmaschine (uranium machine, i.e., nuclear reactor), Georg Joos, along with Hanle, notified Wilhelm Dames, at the Reichserziehungsministerium (REM, Reich Ministry of Education), of potential military applications of nuclear energy. The communication was given to Abraham Esau, head of the physics section of the Reichsforschungsrat (RFR, Reich Research Council) at the REM. On 29 April, a group, organized by Esau, met at the REM to discuss the potential of a sustained nuclear chain reaction. The group included the physicists Walther Bothe, Robert Döpel, Hans Geiger, Wolfgang Gentner (probably sent by Walther Bothe), Wilhelm Hanle, Gerhard Hoffmann, and Georg Joos; Peter Debye was invited, but he did not attend. After this, informal work began at the Georg-August University of Göttingen by Joos, Hanle, and their colleague Reinhold Mannkopff; the group of physicists was known informally as the first Uranverein (Uranium Club) and formally as Arbeitsgemeinschaft für Kernphysik. The group’s work was discontinued in August 1939, when the three were called to military training.

Another notification

The Auergesellschaft had a substantial amount of “waste” uranium from which it had extracted radium. After reading a June 1939 paper by Siegfried Flügge, on the technical use of nuclear energy from uranium, Riehl recognized a business opportunity for the company, and in July he went to the HWA (Heereswaffenamt, Army Ordnance Office) to discuss the production of uranium. The HWA was interested and Riehl committed corporate resources to the task. The HWA eventually provided an order for the production of uranium oxide, which took place in the Auergesellschaft plant in Oranienburg, north of Berlin.

2^nd Uranverein

The second Uranverein began after the Heereswaffenamt (HWA, Army Ordnance Office) squeezed out the Reichsforschungsrat (RFR, Reich Research Council) of the Reichserziehungsministerium (REM, Reich Ministry of Education) and started the formal German nuclear energy project under military auspices. The second Uranverein was formed on 1 September 1939, the day World War II began, and it had its first meeting on 16 September 1939. The meeting was organized by Kurt Diebner, advisor to the HWA, and held in Berlin. The invitees included Walther Bothe, Siegfried Flügge, Hans Geiger, Otto Hahn, Paul Harteck, Gerhard Hoffmann, Josef Mattauch, and Georg Stetter. A second meeting was held soon thereafter and included Klaus Clusius, Robert Döpel, Werner Heisenberg, and Carl Friedrich von Weizsäcker. Also at this time, the Kaiser-Wilhelm Institut für Physik (KWIP, Kaiser Wilhelm Institute for Physics, after WW II the Max Planck Institute for Physics), in Berlin-Dahlem, was placed under HWA authority, with Diebner as the administrative director, and the military control of the nuclear research commenced.

When it was apparent that the nuclear energy project would not make a decisive contribution to ending the war effort in the near term, control of the KWIP was returned in January 1942 to its umbrella organization, the Kaiser-Wilhelm Gesellschaft (KWG, Kaiser Wilhelm Society, after WW II the Max-Planck Gesellschaft), and HWA control of the project was relinquished to the RFR in July 1942. The nuclear energy project thereafter maintained its kriegswichtig (important for the war) designation and funding continued from the military. However, the German nuclear power project was then broken down into the following main areas: uranium and heavy water production, uranium isotope separation, and the Uranmaschine (uranium machine, i.e., nuclear reactor). Also, the project was then essentially split up between a number of institutes, where the directors dominated the research and set their own research agendas. The dominant personnel, facilities, and areas of research were:

• Walther Bothe – Director of the Institut für Physik (Institute for Physcis) at the Kaiser-Wilhelm Institut für medizinische Forschung (KWImF, Kaiser Wilhelm Institute for Medical Research, after 1948 the Max-Planck Institut für medizinische Forschung), in Heidelberg.
  • Measurement of nuclear constants. (6 physicists)

• Klaus Clusius – Director of the Institute for Physical Chemistry at the Ludwig Maximilian University of Munich
  • Isotope separation and heavy water production. (ca. 4 physical chemists and physicists)

• Kurt Diebner – Director of the HWA Versuchsstelle (testing station) in Gottow; Diebner, was also director the RFR experimental station in Stadtilm, Thuringia. He was also an advisor to the HWA on nuclear physics.

• • Measurement of nuclear constants. (ca. 6 physicists)

• Otto Hahn – Director of the Kaiser-Wilhelm-Institut für Chemie (KWIC, Kaiser Wilhelm Institute for Chemistry, after WW II the Max Planck Institut für Chemie - Otto Hahn Institut), in Berlin-Dahlem.
  • Transuranic elements, fission products, isotope separation, and measurement of nuclear constants. (ca. 6 chemists and physicists)

• Paul Harteck – Director of the Physical Chemistry Department of the University of Hamburg.
  • Heavy water production and isotope production. (5 physical chemists, physicists, and chemists)

• Werner Heisenberg – Director of the Department of Theoretical Physics at the University of Leipzig and acting director of the Kaiser-Wilhelm-Institut für Physik (Kaiser Wilhelm Institute for Physics), in Berlin-Dahlem.
  • Uranmaschine, isotope separation, and measurement of nuclear constants. (ca. 7 physicists and physical chemists)

• Hans Kopfermann – Director of the Second Experimental Physics Institute at the Georg-August University of Göttingen.
  • Isotope separation. (2 physicists)

• Nikolaus Riehl – Scientific Director of the Auergesellschaft.
  • Uranium production. (ca. 3 physicists and physical chemists)

• Georg Stetter – Director of the II. Physikalisches Institut (Second Physics Institute) at the University of Vienna.
  • Transuranic elements and measurement of nuclear constants. (ca. 6 physicists and physical chemists)

The point in 1942, when the army relinquished its control of the German nuclear energy project, was the zenith of the project relative to the number of personnel devoting time to the effort. There were only about seventy scientists working on the project, with about forty devoting more than half their time to nuclear fission research. After this, the number of scientists working on applied nuclear fission diminished dramatically. Many of the scientists not working with the main institutes stopped working on nuclear fission and devoted their efforts to more pressing war related work.

On 9 June 1942, Adolf Hitler issued a decree for the reorganization of the RFR as a separate legal entity under the Reichsministerium für Bewaffnung und Munition (RMBM, Reich Ministry for Armament and Ammunition, after autumn 1943 the Reich Ministry for Armament and War Production); the decree appointed Reich Marshal Hermann Göring as the president. The reorganization was done under the initiative of Reich Minister for Armament and Ammunition Albert Speer; it was necessary as the RFR under Minister Bernhard Rust was ineffective and not achieving its purpose. It was the hope that Göring would manage the RFR with the same discipline and efficiency as he had in the aviation sector. A meeting was held on 6 July 1942 to discuss the function of the RFR and set its agenda. The meeting was a turning point in National Socialism’s attitude towards science, as well as recognition that its policies which drove Jewish scientists out of Germany were a mistake, as the Reich needed their expertise. Abraham Esau was appointed on 8 December 1942 as Hermann Göring’s Bevollmächtiger (plenipotentiary) for nuclear physics research under the RFR; in December 1943, Esau was replaced by Walther Gerlach. In the final analysis, placing the RFR under Göring’s administrative control had little effect on the German nuclear energy project.

Over time, the HWA and then the RFR controlled the German nuclear energy project. The most influential people were Kurt Diebner, Abraham Esau, Walther Gerlach, and Erich Schumann. Schumann was one of the most powerful and influential physicists in Germany. Schumann was director of the Physics Department II at the Frederick William University (later, University of Berlin), which was commissioned and funded by the Oberkommando des Heeres (OKH, Army High Command) to conduct physics research projects. He was also head of the research department of the HWA, assistant secretary of the Science Department of the OKW, and Bevollmächtiger (plenipotentiary) for high explosives. Diebner, throughout the life of the nuclear energy project, had more control over nuclear fission research than did Walther Bothe, Klaus Clusius, Otto Hahn, Paul Harteck, or Werner Heisenberg.

Reichspostministerium

In 1928, Manfred von Ardenne came into his inheritance with full control as to how it could be spent, and he established his private research laboratory the Forschungslaboratoriums für Elektronenphysik, in Berlin-Lichterfelde, to conduct his own research on radio and television technology and electron microscopy. He financed the laboratory with income he received from his inventions and from contracts with other concerns. For example, his research on nuclear physics and high-frequency technology was financed by the Reichspostministerium (RPM, Reich Postal Ministry), headed by Wilhelm Ohnesorge. Von Ardenne attracted top-notch personnel to work in his facility, such as the nuclear physicist Fritz Houtermans, in 1940. Ardenne also conducted research on isotope separation.

Heinz Ewald, a member of the Uranverein, had proposed an electromagnetic isotope separator, which was thought applicable to U²³⁵ production and enrichment. Von Ardenne picked up on this and began building a prototype for the RPM. The work was hampered by war shortages and ultimately ended by the war.

Internal reports

Reports from the research conducted were published in Kernphysikalische Forschungsberichte (Research Reports in Nuclear Physics), an internal publication of the Uranverein. The reports 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. The reports are available at the Karlsruhe Nuclear Research Center and the American Institute of Physics.

Individual reports are cited on the pages for some of the research participants in the Uranverein; see for example Friedrich Bopp, Kurt Diebner, Klara Döpel, Robert Döpel, Siegfried Flügge, Paul Harteck, Walter Herrmann, Karl-Heinz Höcker, Fritz Houtermans, Horst Korsching, Georg Joos, Heinz Pose, Carl Ramsauer, Fritz Strassmann, Karl Wirtz, and Karl Zimmer.

Politicization

Two factors which had deleterious effects on the nuclear energy project were the politicization of the education system under National Socialism and the rise of the Deutsche Physik movement, which was anti-Semitic and had a bias against theoretical physics, especially including quantum mechanics.

Emigrations

Adolf Hitler took power on 30 January 1933. On 7 April, the Law for the Restoration of the Professional Civil Service was enacted; this law, and its subsequent related ordnances, politicized the education system in Germany. This had immediate deleterious effects on the physics capabilities of Germany. Furthermore, combined with the deutsche Physik movement, the deleterious effects were intensified and prolonged. The consequences to physics in Germany and its subfield of nuclear physics were multifaceted.

An immediate consequence upon passage of the Law for the Restoration of the Professional Civil Service was that it produced both quantitative and qualitative losses to the physics community. Numerically, it has been estimated that a total of 1,145 university teachers, in all fields, were driven from their posts, which represented about 14% of the higher learning institutional staff members in 1932-1933. Out of 26 German nuclear physicists cited in the literature before 1933, 50% emigrated. Qualitatively, 10 physicists and four chemists who had won or would win the Nobel Prize emigrated from Germany shortly after Hitler came to power, most of them in 1933. These 14 scientists were: Hans Bethe, Felix Bloch, Max Born, Albert Einstein, James Franck, Peter Debye, Dennis Gabor, Fritz Haber, Gerhard Herzberg, Victor Hess, George de Hevesy, Erwin Schrödinger, Otto Stern, and Eugene Wigner. Britain and the USA were often the recipients of the talent which left Germany. The University of Göttingen had 45 dismissals from the staff of 1932-1933, for a loss of 19%. Ironically, eight students, assistants, and colleagues of the Göttingen theoretical physicist Max Born left Europe after Hitler came to power and eventually found work on the Manhattan Project, thus helping the USA, Britain and Canada to develop the atomic bomb; they were Enrico Fermi, James Franck, Maria Goeppert-Mayer, Robert Oppenheimer, Edward Teller, Victor Weisskopf, Eugene Wigner, and John von Neumann. Otto Robert Frisch, who with Rudolf Peierls first calculated the critical mass of U-235 needed for an explosive , was also a Jewish refugee.

Max Planck, the father of the quantum, had been right in assessing the consequences of National Socialist policies. In 1933, Max Planck, as president of the Kaiser Wilhelm Gesellschaft (Kaiser Wilhelm Society), met with Adolf Hitler. During the meeting, Planck told Hitler that forcing Jewish scientists to emigrate would mutilate Germany and the benefits of their work would go to foreign countries. Hitler responded with a rant against Jews and Planck could only remain silent and then take his leave. The National Socialist regime would only come around to the same conclusion as Planck in the 6 July 1942 meeting regarding the future agenda of the Reichsforschungsrat (RFR, Reich Research Council), but by then it was too late.

Heisenberg affair

The politicization of the education system essentially replaced academic tradition and excellence with ideological adherence and trappings, such as membership in National Socialist organizations, such as the Nationalsozialistische Deutsche Arbeiterpartei (NSDAP, National Socialist German Workers Party), the Nationalsozialistischer Deutscher Dozentenbund (NSDDB, National Socialist German University Lecturers League), and the Nationalsozialistischer Deutscher Studentenbund (NSDStB, National Socialist German Student League). The politicization can be illustrated with the conflict which evolved when a replacement for Arnold Sommerfeld was sought in view of his emeritus status. The conflict involved one of the prominent Uranverein participants, Werner Heisenberg.

On 1 April 1935 Arnold Sommerfeld, Heisenberg’s teacher and doctoral advisor at the University of Munich, achieved emeritus status. However, Sommerfeld stayed on as his own temporary replacement during the selection process for his successor, which took until 1 December 1939. The process was lengthy due to academic and political differences between the Munich Faculty’s selection and that of both the Reichserziehungsministerium (REM, Reich Education Ministry) and the supporters of Deutsche Physik. In 1935, the Munich Faculty drew up a candidate list to replace Sommerfeld as ordinarius professor of theoretical physics and head of the Institute for Theoretical Physics at the University of Munich. There were three names on the list: Werner Heisenberg, who received the Nobel Prize in Physics in 1932, Peter Debye, who would receive the Nobel Prize in Chemistry in 1936, and Richard Becker - all former students of Sommerfeld. The Munich Faculty was firmly behind these candidates, with Heisenberg as their first choice. However, supporters of deutsche Physik and elements in the REM had their own list of candidates and the battle commenced, dragging on for over four years. During this time, Heisenberg, came under vicious attack by the supporters of deutsche Physik. One such attack was published in Das Schwarze Korps, the newspaper of the Schutzstaffel, or SS, headed by Heinrich Himmler. In the editorial, Heisenberg was called a “White Jew” who should be made to “disappear.” These verbal attacks were taken seriously, as Jews were subject to physical violence and incarceration at the time. Heisenberg fought back with an editorial and a letter to Himmler, in an attempt to get a resolution to this matter and regain his honor. At one point, Heisenberg’s mother visited Himmler’s mother to help bring a resolution to the affair. The two women knew each other as a result of Heisenberg’s maternal grandfather and Himmler’s father being rectors and members of a Bavarian hiking club. Eventually, Himmler settled the Heisenberg affair by sending two letters, one to SS-Gruppenführer Reinhard Heydrich and one to Heisenberg, both on 21 July 1938. In the letter to Heydrich, Himmler said Germany could not afford to lose or silence Heisenberg as he would be useful for teaching a generation of scientists. To Heisenberg, Himmler said the letter came on recommendation of his family and he cautioned Heisenberg to make a distinction between professional physics research results and the personal and political attitudes of the involved scientists. The letter to Heisenberg was signed under the closing “Mit freundlichem Gruss und, Heil Hitler!” (With friendly greetings, Heil Hitler!”) Overall, the settlement of the Heisenberg affair was a victory for academic standards and professionalism. However, the replacement of Sommerfeld by Wilhelm Müller on 1 December 1939 was a victory of politics over academic standards. Müller was not a theoretical physicist, had not published in a physics journal, and was not a member of the Deutsche Physikalische Gesellschaft (DPG, German Physical Society); his appointment as a replacement for Sommerfeld was considered a travesty and detrimental to educating a new generation of theoretical physicists.

Missing generation of physicists

Politicization of the academic community, combined with the impact of the deutsche Physik movement and other policies, such as drafting physicists to fight in the war (e.g., Paul O. Müller, a member of the Uranverein who was killed at the Russian front), had the net effect of bringing about a missing generation of physicists. At the close of the war, physicists born between 1915 and 1925 were almost nonexistent.

Autonomy and accommodation

Members of the Uranverein, Wolfgang Finkelnburg, Werner Heisenberg, Carl Ramsauer, and Carl Friedrich von Weizsäcker were effective in countering the politicization of academia and effectively putting an end to the influence of the deutsche Physik movement. However, in order to do this they were, as were many scientists, caught between autonomy and accommodation. Essentially, they would have to legitimize the National Socialist system by compromise and collaboration.

During the period in which deutsche Physik was gaining prominence, a foremost concern of the great majority of scientists was to maintain autonomy against political encroachment. Some of the more established scientists, such as Max von Laue, could demonstrate more autonomy than the younger and less established scientists. This was, in part, due to political organizations, such as the Nationalsozialistischer Deutscher Dozentenbund (National Socialist German University Lecturers League), whose district leaders had a decisive role in the acceptance of an Habilitationsschrift, which was a prerequisite to attaining the rank of Privatdozent necessary to becoming a university lecturer. While some with ability joined such organizations out of tactical career considerations, others with ability and adherence to historical academic standards joined these organizations to moderate their activities. This was the case of Finkelnburg. It was in the summer of 1940 that Finkelnburg became an acting director of the NSDDB at Technische Hochschule Darmstadt. As such, he organized the Münchner Religionsgespräche, which took place on 15 November 1940 and was known as the Munich Synod . The Münchner Religionsgespräche was an offensive against deutsche Physik. While the technical outcome may have been thin, it was a political victory against deutsche Physik. Also, in part, it was Finkelnburg’s role in organizing this event that influenced Carl Ramsauer, as president of the Deutsche Physikalische Gesellschaft, to select Finkelnburg in 1941 as his deputy. Finkelnburg served in this capacity until the end of World War II.

Early in 1942, as president of the DPG, Ramsauer, on Felix Klein’s initiative and with the support of Ludwig Prandtl, submitted a petition to Reich Minister Bernhard Rust, at the Reichserziehungsministerium (Reich Education Ministry). The petition, a letter and six attachments, addressed the atrocious state of physics instruction in Germany, which Ramsauer concluded was the result of politicization of education.

Exploitation and denial

Near the end of World War II, the principal Allied war powers 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 exploitations, denial was an element of their efforts, i.e., the Americans and Russians conducted their respective operations to try to deny German technology, personnel, and materiel to the other party. Application of denial often meant getting there first, which to some extent put the Russians at a disadvantage in some geographic locations, even if the area was to be in the Russian zone of occupation. When it came to applications of exploitation and denial, all parties were sometimes heavy-handed.

A general United States denial and exploitation effort was Operation Paperclip. 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 Russian operation, if it had one, it has been referred to by 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 latter years of the war.

Unfortunately for the Russians, 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 Ludwig Bewilogua, who was in charge of the exponential uranium pile.

Nine of the prominent German scientists who published reports in Kernphysikalische Forschungsberichte as members of the Uranverein were picked up by Operation Alsos and incarcerated in England under 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 energy project. Goudsmit, the chief scientific advisor to Operation Alsos, thought von Laue might be beneficial to the postwar rebuilding of Germany and would benefit from the high level contacts he would have in England.

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 strength’s of the Degussa corporation’s capabilities in metals production.

The Auergesellschaft 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 Auergesellschaft 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 Russian troops would get there before the 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 Russians. 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 Russians and said that the facility was mostly destroyed. Riehl also recalled long after the war that the Russians 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, when most of the KWIP was evacuated to Hechingen in Southern Germany due to air raids on Berlin, he went there too, and he was the Institute’s Deputy Director there. 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 Russian 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 Hermann Schüler, 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 “requisition” equipment, materiel, intellectual property, and personnel useful to the Soviet atomic bomb project. The exploitation teams were under the Soviet Alsos and they were headed by Lavrentij 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 Berlin (today, the 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: Werner Czulius, 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 in Sungul’.

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 Electrochemisty, today the Fritz Haber Institute of the Max-Planck Society), and Max Volmer, director of the Physical Chemistry Institute at the Berlin Technische Hochschule, 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 Nationalsozialistische Deutsche Arbeiterpartei, 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 of the Manhattan Project and the Uranverein

The joint American, British, and Canadian Manhattan Project developed the uranium and plutonium atomic bombs, which helped bring an end to hostilities with Japan during World War II. Its success is attributable to meeting all four of the following conditions:

1. A strong initial drive, by a small group of scientists, to launch the project.
2. Unconditional government support from a certain point in time.
3. Essentially unlimited manpower and industrial resources.
4. A concentration of brilliant scientists devoted to the project.

Even with all four of these conditions in place the Manhattan Project succeeded only after the war in Europe had been brought to a conclusion. In Germany however only the first condition was met, and then only in a weaker sense than for the Manhattan Project. Further, mutual distrust existed between the German government and the scientists.

For the Manhattan Project, the second condition was met on 9 October 1941 or shortly thereafter. Significant here is that by the end of 1941 it was already apparent that the German nuclear energy project would not make a decisive contribution to ending the German war effort in the near term, and control of the project was relinquished by the Heereswaffenamt (HWA, Army Ordnance Office) to the Reichsforschungsrat (RFR, Reich Research Council) in July 1942, making it in essence a mere research project with objectives far short of making a weapon.

Concerning condition three, the needs in materiel and manpower for a large-scale project necessary for the separation of isotopes for a uranium-based bomb and heavy water production for reactors for a plutonium-based bomb may have been possible in the early years of the war, but in the latter years it would have been impossible to mount such an effort. Also, these large-scale facilities would have been recognized and included as targets for the Allied bombing missions, which grew in intensity as the war continued.

As to condition four, the high priority allocated to the Manhattan Project allowed for the recruitment and concentration of capable scientists on the project; in Germany, the priority and a focused project for such recruitment and concentration of personnel did not exist past mid-1942.

Thus, weakly meeting only the first of these four conditions, Germany fell far short of what was required to make an atomic bomb.

Recent developments

A book by Rainer Karlsch, Hitlers Bombe, published in 2005, alleged that Diebner's team tested conducted the first successful nuclear weapon test of some type of nuclear related device in Ohrdruf, Thuringia on 4 March 1945.. However, Karlsch has been criticized for displaying "a catastrophic lack of understanding of physics" by physicist Michael Schaaf, who is himself the author of an earlier book about Nazi atomic research, while Karlsch himself has acknowledged that he lacked absolute proof for the claims made in his book.

Science historian Mark Walker also published his analysis in 2005., and in 2005 Karlsch and Walker published an article on the controversial historical evidence, briefly referenced in the article. The Physikalisch-Technische Bundesanstalt (PTB, Federal Physical and Technical Institute) tested soil samples in the area of the alleged test, and in 2006 it issued its results: keinen Befund (nothing found). Karlsch published a follow-on book with Heinko Petermann to elaborate on issues raised in his first book.

See also

• Copenhagen (play)
• Enriched uranium
• Hanford Site
• History of nuclear weapons
• Isotope separation
• Japanese atomic program
• List of countries with nuclear weapons
• Los Alamos National Laboratory
• Manhattan Project
• Metallurgical Laboratory
• Norwegian heavy water sabotage
• Nuclear weapon
• Oak Ridge, Tennessee
• Operation Alsos
• Soviet atomic bomb project
• Zippe-type centrifuge

Bibliography

• Bernstein, Jeremy Hitler’s Uranium Club: The Secret Recording’s at Farm Hall (Copernicus, 2001) ISBN 0-387-95089-3

• Bernstein, Jeremy Heisenberg and the critical mass, Am. J. Phys. Volume 70, Number 9, 911-916 (2002)

• Bernstein, Jeremy Heisenberg in Poland, Am. J. Phys. Volume 72, Number 3, 300-304 (2004). See also Letters to the Editor by Klaus Gottstein and a reply by Jeremy Bernstein in Am. J. Phys. Volume 72, Number 9, 1143-1145 (2004).

• Beyerchen, Alan D. Scientists Under Hitler: Politics and the Physics Community in the Third Reich (Yale, 1977) ISBN 0-300-01830-4

• Gimbel, John U.S. Policy and German Scientists: The Early Cold War, Political Science Quarterly Volume 101, Number 3, 433-451 (1986)

• Gimbel, John Science, Technology, and Reparations: Exploitation and Plunder in Postwar Germany (Stanford, 1990)

• Goudsmit, Samuel with an introduction by R. V. Jones Alsos (Toamsh, 1986)

• Heisenberg, Werner Research in Germany on the Technical Applications of Atomic Energy, Nature Volume 160, Number 4059, 211-215 (August 16, 1947). See also the annotated English translation: Document 115. Werner Heisenberg: Research in Germany on the Technical Application of Atomic Energy [August 16, 1947] in Hentschel, Klaus (editor) and Ann M. Hentschel (editorial assistant and translator) Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996) 361-379.

• Hentschel, Klaus (editor) and Ann M. Hentschel (editorial assistant and translator) Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996) ISBN 0-8176-5312-0. [This book is a collection of 121 primary German documents relating to physics under National Socialism. The documents have been translated and annotated, and there is a lengthy introduction to put them into perspective.]

• Hoffmann, Dieter Between Autonomy and Accommodation: The German Physical Society during the Third Reich, Physics in Perspective 7(3) 293-329 (2005)

• Kant, Horst Werner Heisenberg and the German Uranium Project / Otto Hahn and the Declarations of Mainau and Göttingen, Preprint 203 (Max-Planck Institut für Wissenschaftsgeschichte, 2002)

• Landsman, N. P. Getting even with Heisenberg, Studies in History and Philosophy of Modern Physics Volume 33, 297-325 (2002)

• Macrakis, Kristie Surviving the Swastika: Scientific Research in Nazi Germany (Oxford, 1993)

• Mehra, Jagdish and Helmut Rechenberg The Historical Development of Quantum Theory. Volume 6. The Completion of Quantum Mechanics 1926-1941. Part 2. The Conceptual Completion and Extension of Quantum Mechanics 1932-1941. Epilogue: Aspects of the Further Development of Quantum Theory 1942-1999. (Springer, 2001) ISBN 978-0-387-95086-0

• Norman M. Naimark The Russians in Germany: A History of the Soviet Zone of Occupation, 1945-1949 (Belkanp, 1995)

• Riehl, Nikolaus and Frederick Seitz Stalin’s Captive: Nikolaus Riehl and the Soviet Race for the Bomb (American Chemical Society and the Chemical Heritage Foundations, 1996) ISBN 0-8412-3310-1.

• Oleynikov, Pavel V. German Scientists in the Soviet Atomic Project, The Nonproliferation Review Volume 7, Number 2, 1 – 30 (2000). The author has been a group leader at the Institute of Technical Physics of the Russian Federal Nuclear Center in Snezhinsk (Chelyabinsk-70).

• Walker, Mark German National Socialism and the Quest for Nuclear Power 1939–1949 (Cambridge, 1993) ISBN 0-521-43804-7

• Walker, Mark Eine Waffenschmiede? Kernwaffen- und Reaktorforschung am Kaiser-Wilhelm-Institut für Physik, Forschungsprogramm „Geschichte der Kaiser-Wilhelm-Gesellschaft im Nationalsozialismus“ Ergebnisse 26 (2005)

Further reading

• Albrecht, Ulrich, Andreas Heinemann-Grüder, and Arend Wellmann Die Spezialisten: Deutsche Naturwissenschaftler und Techniker in der Sowjetunion nach 1945 (Dietz, 1992, 2001) ISBN 3320017888

• Bernstein, Jeremy and David Cassidy Bomb Apologetics: Farm Hall, August 1945, Physics Today Volume 48, Issue 8, Part I, 32-36 (1995)

• Beyerchen, Alan What We Know About Nazism and Science, Social Research Volume 59, Number 3, 615-641 (1992)

• Bethe, Hans A. The German Uranium Project, Physics Today Volume 53, Issue 7, 34-36

• Cassidy, David C. Heisenberg, German Science, and the Third Reich, Social Research Volume 59, Number 3, 643-661 (1992)

• Cassidy, David C. Uncertainty: The Life and Science of Werner Heisenberg (Freeman, 1992)

• Cassidy, David C. A Historical Perspective on Copenhagen, Physics Today Volume 53, Issue 7, 28 (2000). See also Heisenberg’s Message to Bohr: Who Knows, Physics Today Volume 54, Issue 4, 14ff (2001), individual letters by Klaus Gottstein, Harry J. Lipkin, Donald C. Sachs, and David C. Cassidy.

• Eckert, Michael Werner Heisenberg: controversial scientist physicsweb.org (2001)

• Heisenberg, Werner Die theoretischen Grundlagen für die Energiegewinnung aus der Uranspaltung, Zeitschrift für die gesamte Natruwiessenschaft, Volume 9, 201-212 (1943). See also the annotated English translation: Document 95. Werner Heisenberg. The Theoretical Basis for the Generation of Energy from Uranium Fission [February 26, 1942] in Hentschel, Klaus (editor) and Ann M. Hentschel (editorial assistant and translator) Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996) 294-301.

• Heisenberg, Werner, introduction by David Cassidy, translation by William Sweet A Lecture on Bomb Physics: February 1942, Physics Today Volume 48, Issue 8, Part I, 27-30 (1995)

• Hentschel, Klaus The Metal Aftermath: The Mentality of German Physicists 1945-1949 (Oxford, 2007)

• Hoffmann, Dieter Zwischen Autonomie und Anpassung: Die Deutsche Physikalische Gesellschaft im Dritten Reich, Max-Planck-Institut für Wissenschafts Geschichte Preprint 192 (2001)

• Hoffmann, Dieter and Mark Walker The German Physical Society Under National Socialism, Physics Today 57(12) 52-58 (2004)

• Hoffmann, Dieter Between Autonomy and Accommodation: The German Physical Society during the Third Reich, Physics in Perspective 7(3) 293-329 (2005)

• Hoffmann, Dieter and Mark Walker Zwischen Autonomie Und Anpassung, Physik Journal Volume 5, Number 3, 53-58 (2006)

• Hoffmann, Dieter and Mark Walker Peter Debye: “A Typical Scientist in an Untypical Time” Deutsche Physikalische Gesellschaft (2006)

• Hoffmann, Dieter and Mark Walker (editors) Physiker Zwischen Autonomie Und Anpassung (Wiley-VCH, 2007)

• Karlsch Rainer Hitlers Bombe. Die geheime Geschichte der deutschen Kernwaffenversuche. (Dva, 2005)

• Karlsch, Rainer and Heiko Petermann Für und Wider “Hitlers Bombe” (Waxmann, 2007)

• Krieger, Wolfgang The Germans and the Nuclear Question German Historical Institute Washington, D.C., Occasional Paper No. 14 (1995)

• Pash, Boris T. The Alsos Mission (Award, 1969)

• Powers, Thomas Heisenberg’s War: The Secret History of the German Bomb (Knopf, 1993)

• Renneberg, Monika and Mark Walker Science, Technology and National Socialism (Cambridge, 1994, first paperback edition 2002)

• Rhodes, Richard The Making of the Atomic Bomb (Simon and Schuster, 1986)

• Rose, Paul Lawrence, Heisenberg and the Nazi Atomic Bomb Project: A Study in German Culture (California, 1998). For a critical review of this book, please see: Landsman, N. P. Getting even with Heisenberg, Studies in History and Philosophy of Modern Physics Volume 33, 297-325 (2002).

• Schaaf, Michael Heisenberg, Hitler und die Bombe. Gespraeche mit Zeitzeugen. (GNT-Verlag, 2001)

• Schumann, Erich Wehrmacht und Froschung in Richard Donnevert (editor) Wehrmact und Partei second expanded edition, (Barth, 1939) 133-151. See also the annotated English translation: Document 75. Erich Schumann: Armed Forces and Research [1939] in Hentschel, Klaus (editor) and Ann M. Hentschel (editorial assistant and translator) Physics and National Socialism: An Anthology of Primary Sources (Birkhäuser, 1996) 207-220.

• Sime, Ruth Sime From Exceptional Prominence to Prominent Exception: Lise Meitner at the Kaiser Wilhelm Institute for Chemistry Ergebnisse 24 Forschungsprogramm Geschichte der Kaiser-Wilhelm-Gesellschaft im Nationalsozialismus (2005).

• Ruth Lewin Sime The Politics of Memory: Otto Hahn and the Third Reich, Physics in Perspective Volume 8, Number 1, 3-51 (2006). Sime is retired from teaching chemistry at Sacramento City College.

• Walker, Mark National Socialism and German Physics, Journal of Contemporary Physics Volume 24, 63-89 (1989)

• Walker, Mark Heisenberg, Goudsmit and the German Atomic Bomb, Physics Today Volume 43, Issue 1, 52-60 (1990)

• Walker, Mark Nazi Science: Myth, Truth, and the German Atomic Bomb (Perseus, 1995)

• Walker, Mark German Work on Nuclear Weapons, Historia Scientiarum; International Journal for the History of Science Society of Japan, Volume 14, Number 3, 164-181 (2005)

• Walker, Mark Eine Waffenschmiede? Kernwaffen- und Reaktorforschung am Kaiser-Wilhelm-Institut für Physik, Forschungsprogramm „Geschichte der Kaiser-Wilhelm-Gesellschaft im Nationalsozialismus“ Ergebnisse 26 (2005)

• Mark Walker Otto Hahn: Responsibility and Repression, Physics in Perspective Volume 8, Number 2, 116-163 (2006). Mark Walker is Professor of History at Union College in Schenectady, New York.

External links

• (February 2002) Aaserud, Finn Release of documents relating to 1941 Bohr-Heisenberg meeting
• GlobalSecurity.org German Special Weapons
• Niels Bohr Archive Release of documents relating to 1941 Bohr-Heisenberg meeting (6 February 2002)
• (June 2008) Annotated bibliography on the German atomic bomb project from the Alsos Digital Library for Nuclear Issues
• Walker, Mark Nazi's & the Bomb from Public Broadcasting Service Nova episode, Hitler's Sunken Secret (originally aired 2005-11-08).