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 (Reichsforschungsrat) while continuing to fund the activity.

Diebner, throughout the life of the nuclear weapon project, had more control over nuclear-fission research than did Walther Bothe, Klaus Clusius, Otto Hahn, Paul Harteck, or Werner Heisenberg.

[2][3] With the war in Europe ending in the spring of 1945, various Allied powers competed with each other to obtain surviving components of the German nuclear industry (personnel, facilities, and materiel), as they did with the pioneering V-2 SRBM program.

On 19 December 1938, eighteen days before the publication, Otto Hahn communicated these results and his conclusion of a bursting of the uranium nucleus in a letter to his colleague and friend Lise Meitner, who had fled Germany in July to the Netherlands and then to Sweden.

[7][8] On 22 April 1939, after hearing a colloquium paper by his colleague Wilhelm Hanle at the University of Göttingen proposing the use of uranium fission in an 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 and economic applications of nuclear energy.

[13] Also independently of the first Uranverein, Nikolaus Riehl, the head of the scientific headquarters at Auergesellschaft (usually known as just "Auer"), a German industrial firm, read a June 1939 paper by Siegfried Flügge, on the technical use of nuclear energy from uranium.

[13] Army Ordnance eventually provided an order for the production of uranium oxide, which took place in the Auer plant in Oranienburg, north of Berlin.

In August 1939, just before the German invasion of Poland precipitated the formal start of World War II, the Army Ordnance Office (HWA) moved to take over the work of the Reichsforschungsrat (RFR, Reich Research Council) of the Reich Education Ministry (REM), and ordered the RFR to halt all experiments and work on nuclear energy.

[19][20] The invitees to this meeting included Walther Bothe, Siegfried Flügge, Hans Geiger, Otto Hahn, Paul Harteck, Gerhard Hoffmann, Josef Mattauch, and Georg Stetter.

The meeting was a turning point in Nazi attitudes towards science, as well as recognition that the policies which drove Jewish scientists out of Germany were a mistake, as the Reich needed their expertise.

For example, his research on nuclear physics and high-frequency technology was financed by the Reichspostministerium (RPM, Reich Postal Ministry), headed by Wilhelm Ohnesorge.

It includes one of the most detailed presentations of contemporary German knowledge about the various processes of isotope separation, and recommends their combined usage to get to sufficient amounts of enriched uranium.

Walther Gerlach refused to print this textbook, but it is preserved as a typed manuscript and it appeared after the War in 1948 virtually unchanged (with just a few additions on the US atomic bomb released in 1945).

[48][49][50][51][52] The best known US denial and exploitation 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.

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.

[54][55] 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.

[57] 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.

Ultimately, nine of the prominent German scientists who published reports in Kernphysikalische Forschungsberichte as members of the Uranverein[59] 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.

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.

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 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.

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.

[67][68] 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[69] 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.

[17][70] 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.

[87] The United States, British, and Canadian governments worked together to create the Manhattan Project that developed the uranium and plutonium atomic bombs.

In June 1942, some six months before the American Chicago Pile-1 achieved man-made criticality for the first time anywhere, Döpel's L-IV "Uran-Maschine" was destroyed by a chemical explosion introduced by oxygen,[99] which finished the work on this topic at Leipzig.

Thereafter, despite increased expenditures, the Berlin groups and their extern[clarification needed] branches did not succeed in getting a reactor critical until the end of World War II.

German historian Klaus Hentschel summarizes the organizational differences as: The Manhattan Project's Alsos investigation ultimately concluded in a classified report, on the basis of documents and materials confiscated from research sites in Germany, Austria, and France, as well as interrogation of over 40 personnel connected with the program, that: In terms of financial and human resources, the comparisons between the Manhattan Project and the Uranverein are stark.