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How close did Hitler really come to getting ‘the Bomb’?
Today, that reassuring view is being nibbled away by the evidence from secret documents trickling out of private or former Soviet archives. Hidden for six decades, these papers confirm that Hitler's scientists indeed were way behind their Manhattan Project counterparts in building a Bomb. But the documents also suggest that by the end of the war in Europe, in May 1945, the Nazis had advanced farther down the nuclear road than is conventionally thought and had struck out in unexpected directions. As early as 1942, the Germans had already cracked some of the biggest conceptual problems behind making an atomic bomb. As the Reich's enemies closed in during the final months of the war, the scientists made some extraordinary technical strides. Using a prototype reactor hastily assembled in a disused beer cellar in southwestern Germany, a team nearly achieved a self-sustaining chain reaction, the key step to manufacturing nuclear explosive. According to two new documentary finds unveiled this year, Hitler's scientists even tested a nuclear weapon. The device that these days would be called a "dirty" bomb. The Reich scientists also sketched plans for the world's first mini-nuke missile. The Nazis were not at all close to having an atomic bomb like those dropped on Hiroshima and Nagasaki in August 1945. The German progress towards such weapons was comparable to what the Americans had achieved by the summer of 1942. During the last desperate year-and-a-half of war... a group of physicists who had been working on nuclear reactors, nuclear reactions and hollow-point arrangements of high explosives put them together to test a nuclear device. ~ Mark Walker, a professor of history at Union College in Schenectady, New York. Work in atomic physics before World War II led scientists in Germany, as well as in Britain and the United States, to speculate that an awesome release of energy could be obtained if the nucleus of a heavy atomic isotope was split apart, its neutrons wacking into other atoms in a chain reaction. Prompted by warnings from Albert Einstein to President Roosevelt of the Nazis' interest in a bomb, the United States launched the Manhattan Project on Dec. 7 1941, coincidentally the eve of the attack on Pearl Harbor that prompted its entry into World War II. The scheme would cost the equivalent of some 30 billion dollars and muster thousands of scientists and engineers, many of them Jewish scientists who had fled Nazi prosecution of their crimes. That same winter, the German military looked into the prospects for a Bomb and concluded the goal was so tough it was not worth the huge investment of billions. As a result, Germany's so-called "Uranium Project" was a diffuse affair, gathering between 50 and 100 scientists, scattered across the country and prone to disagrements. Many of them did not devote their efforts full-time to nuclear weapons research and their access to raw materials and brainpower was constrained by allied raids and conscription. After the war, American physicist Samuel Goudsmit investigated the Nazi nuclear effort. In his account, published in 1947, Goudsmit said the lead German physicist, the world-renowned theoretician Werner Heisenberg, had vastly overestimated the amount of uranium 235 needed for an explosion, or critical mass. Heisenberg also failed to understand that plutonium, a by-product of enriching uranium, could also be a fissile material and in fact was an even better fuel for a bomb than uranium 235, Goudsmit said. (Plutonium was used for the Nagasaki bomb). But the traditional picture of German incompetence has been proven wrong by documentary finds, says Walker. As early as February 1942, a German military overview of the Uranium Project concluded that critical mass could be achieved with "around 10-100 kilos" (22-220 pounds) of enriched uranium, a figure comparable to the Manhattan Project's own early estimate, of two to 100 kilos (4.4 to 220 pounds). And newly unearthed Russian documents show that in 1941 Heisenberg drafted a de-facto patent application for a plutonium bomb, although he referred to the substance as "element 94" in relation to its position on chemistry's periodic table, says Walker. What is already known is that Heisenberg's organisational rival, German army physicist Kurt Diebner, pushed ahead with a design for a reactor which was tested in February 1945 in the village of Haigerloch, near Tübingen. It came within a whisker of achieving a self-sustaining chain reaction, although if it had worked, the scientists would have been exposed to lethal levels of radiation, allied experts who discovered the device found. In a controversial book, Hitlers Bombe, published this March 2005, independent German historian Rainer Karlsch said Diebner's team also tested a nuclear device in Thuringia, eastern Germany, on March 4, 1945, killing several hundred inmates. The device was not a weapon in the Hiroshima style, Karlsch says. Instead, it appears to have been an attempt to use high explosives to provoke fission in a hoard of enriched uranium and fusion in a batch of deuterium compounds, creating a fierce, localised, highly radioactive blast. Karlsch bases his claim on eyewitness accounts and a Soviet military espionage report. But the details are sparse and Karlsch has been savaged in some quarters. Even so, this astonishing tale is clearly not over. "More archival material continues to be found, and is still trickling out of Russian archives right now," says Walker. "I do not expect any more major surprises...but that is what I thought in 1989, when my first book on the Nazis' nuclear program was published." |
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Saturday, March 5, 2005 Hitler won atomic bomb race, but couldn't drop it By Ernest Gill in Hamburg ADOLF Hitler had the atom bomb first but it was too primitive and ungainly for aerial deployment, says a new book that indicates the race to split the atom was much closer than is believed. Nazi scientists carried out tests of what would now be called a dirty nuclear device in the waning days of World War II, writes Rainer Karlsch, a German historian, in his book Hitler's Bomb, to be be published this month. Concentration camp inmates were used as human guinea pigs and "several hundred" died in the tests, conducted on the Baltic Sea island of Rügen and at an inland test in wooded hill country about 100 kilometres south of Berlin in 1944 and early 1945. Karlsch, 47, author of a number of books on Cold War espionage and the nuclear arms race, supports his findings on what his publishers call hitherto unpublished documents, scientific reports and blueprints.ONT> A US historian, Mark Walker, an expert on the Third Reich's atomic weapons program, lent his support to Karlsch's claims on Thursday. "I consider the arguments very convincing," he said. However, Hitler's atomic weapon did not approach the devastating potential of the US bombs dropped on Hiroshima and Nagasaki, said Professor Walker, a history professor at Union College in Schenectady, New York state. He said the weapon secretly developed and tested by Nazi scientists was more comparable to a dirty bomb, nuclear material encased in explosives. Professor Walker praised Karlsch for writing "a whole new chapter" on Hitler's search for the "wonder weapon". Hitler's claims that his scientists were working on the "wonder weapon" have been dismissed as the rantings of a desperate and deranged man. But Karlsch's book lends credence to the possibility that Hitler may have been closer to getting his hands on that weapon than anyone has previously believed. It was known that German scientists had carried out heavy-water experiments in an attempt to split the atom, using research facilities in Norway and elsewhere. But it was widely believed that Nazi scientists had been hampered by a lack of pure-grade uranium, which was almost non-existent outside North America and Africa. It was also surmised that Hitler had favoured conventional weapons over nuclear arms because his limited grasp of strategic warfare prevented him from seeing the ramifications of nuclear capability. It was believed that he had discouraged development of the atom bomb. But Karlsch says he found documented proof of the existence of a nuclear reactor and nuclear weapons testing sites. His publishers, Deutsche Verlags-Anstalt, said his work was based on four years of painstaking research and interviews with independent historians. Among the most compelling pieces of evidence is a 1941 patent draft for a plutonium bomb, said Markus Desaga, a spokesman for the publisher. "He also based his research on contemporary research reports, construction blueprints, aerial surveillance photos, notebooks of some of the scientists involved as well as espionage reports by US and Soviet agents," Mr Desaga said. "He also based his findings on radiation measurements and soil analysis." |
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Book: By Tony Czuczka BERLIN - Nazi scientists trying to build an atomic bomb set off a test explosion two months before the end of World War II, killing hundreds of people in eastern Germany, a German researcher claims in a book published Monday. "Hitler's Bomb" theorizes that the March 1945 device didn't achieve fission, but did scatter telltale radioactive particles at the Ohrdruf test site. It also claims that Nazi Germany briefly had a working nuclear reactor, something historians generally dispute. Author Rainer Karlsch, an economic historian, offers no first-hand proof, saying his account is an interpretation of available evidence and he hopes it will spur more research. He said soil samples from the Ohrdruf site he had analyzed for his book turned up above-average levels of radioactive isotopes such as cesium 137 and cobalt 60, though he quotes the testers as saying the site poses no radiation hazard. However, access to what he believes was ground zero was barred because of old munitions at the site, which served as a Soviet military training area in East Germany after the war. A U.S. mission that arrived in Germany with American troops in 1945 to investigate the German atomic bomb program concluded that the Germans were nowhere near making a nuclear weapon. Karlsch doesn't claim they were near. But based on witness accounts recorded after the war, postwar Allied aerial photos and Soviet military intelligence reports, he argues that a test blast happened March 3, 1945, at Ohrdruf -- then being run as a Nazi concentration camp. He says there probably were several previous tests. "Hitler's bomb -- a tactical nuclear weapon with a potential for destruction far below that of the two American atomic bombs -- was tested successfully several times shortly before the end of the war," the book says. Gerald Holton, a professor of physics and the history of science at Harvard University, said the main scientists in the Nazi atomic bomb program never mentioned a test blast or having built a working nuclear reactor. British intelligence bugged the scientists -- including a key planner, Walther Gerlach -- while they were interned at Farm Hall manor in England after the war. Any claims of a Nazi test blast "would have to have a lot of documentary evidence behind it," Holton said. "It also would have to be checked against the remarks that Gerlach made during his period at Farm Hall ... where none of that sort of planning was discussed by him or anyone else." Karlsch says scientists around Gerlach had "a certain amount" of enriched uranium from an as yet unknown source. The German device probably was a 2-ton cylinder containing enriched uranium, he writes. The amount of uranium was small, meaning the conventional explosives used to trigger the device did not set off a vastly more destructive nuclear chain reaction, Karlsch said. That would mesh with an account Karlsch said he found in Soviet military archives, apparently based on information from a German informant, that said the blast felled trees within a radius of about 500 to 600 yards. Witnesses reported a bright flash of light and a column of smoke over the area that day, and residents said they had nausea and nosebleeds for days afterward, Karlsch says. One witness said he helped burn heaps of corpses inside the military area the next day. They were hairless and some had blisters and "raw, red flesh." Karlsch concludes that the blast killed several hundred prisoners of war and inmates forced to work at the site. Two months later, on May 8, 1945, Nazi Germany surrendered after the Soviets captured Berlin. The book also seeks to turn attention from famous physicists like Werner Heisenberg and Carl Friedrich von Weizsäcker -- who historians believe were often ambivalent about building a nuclear bomb for Hitler -- to lesser-known but fiercely ambitious scientists and Nazi officials who Karlsch theorizes were directly involved in the testing program. Physicist Jeremy Bernstein, who edited the Farm Hall transcripts for the book "Hitler's Uranium Club: The Secret Recordings at Farm Hall," said a key question was where the enriched uranium could have come from. "To enrich uranium, you need an plant the size of Oak Ridge, and the Germans never had one," he said, referring to the sprawling U.S. facility that produced enriched uranium for the Hiroshima bomb. Russian officials were unaware of any such test by the Germans, said Nikolai Shingaryov, a spokesman for Russia's Federal Nuclear Agency. "Of course we don't know everything, but we don't have data about this," he said.
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The German nuclear energy project was an endeavor by scientists during World War II in Nazi Germany to develop nuclear energy and an atomic bomb for practical use. Unlike the competing Allied effort to develop a nuclear weapon the German effort resulted in two rival teams, one working for the military, the second, a civilian effort co-ordinated by the German Post Office. Overview The nuclear research effort most widely discussed was that of the Kaiser Wilhelm Institute team led by the physicist Werner Heisenberg. The second was a military team under the scientific leadership of Prof. Kurt Diebner. This military team was also associated with Dr. Paul Harteck who helped to develop the gaseous uranium centrifuge invented by Dr. Erich Bagge in 1942. Their team was part of the German Army (Heereswaffenamt Forschungsstelle E), the Kriegsmarine (navy) had a subsidiary team looking at nuclear propulsion for U-boats under Dr. Otto Haxel. Konteradmiral Karl Witzell and Konteradmiral Wilhelm Rein were military leaders of the naval nuclear project. The intentions of Heisenberg's team are a matter of historical controversy, centering on whether or not the scientists involved were genuinely attempting to build an atomic bomb for Nazi dictator Adolf Hitler. The project was not a military success by any measure. Effectiveness and implications It is generally accepted that the Nuclear Age began with the 1938 publication by Otto Hahn and Fritz Strassman of results that proved Enrico Fermi had observed the bursting of a uranium nucleus, in other words: nuclear fission. Immediately afterwards, Lise Meitner and Otto Robert Frisch described the theoretical mechanisms of fission and revealed that large amounts of binding energy was released in the process. Thus by the beginning of World War II the scientific community was well aware of the early German lead in this area of theoretical physics. The threat of a Nazi atomic bomb was one of the primary driving forces behind the creation of the British TUBE ALLOYS project which would eventually lead to the Allied nuclear weapons effort under Robert Oppenheimer: the Manhattan Project. (Several Germans eventually would make significant contributions to the Allied nuclear effort.) The German government never did finance a full crash program to develop weapons, as they estimated it could not be completed in time for use in the war, thus the German program was much more limited in capacity and ability when compared to the eventual size and priority of the Manhattan Project. In 1945, a U.S. investigation called Project ALSOS determined that German scientists had only almost reached the point that Allied scientists had reached in 1942, the creation of a sustained nuclear chain reaction, a crucial step for creating a nuclear reactor (which in turn could be used for either peaceful purposes, or for creating plutonium, needed for nuclear weapons). There has been a historical debate, however, as to whether the German scientists purposefully sabotaged the project by under-representing their chances at success, or whether their estimates were based in either error or inadequacy. Post war After the war, a number of German scientists including Heisenberg, Otto Hahn (who had co-discovered nuclear fission), and Max von Laue (an ardent anti-Nazi), were taken captive by Allied forces and put under secret watch at Farm Hall, England, as part of Operation Epsilon. Their conversations were recorded as Allied analysts attempted to discover the extent of German knowledge about nuclear weapons. The results were inconclusive, but they allowed them to hear the results of the atomic bombing of Hiroshima, Japan, which sent Hahn into a near-suicidal despair. By the next morning, Heisenberg claimed to have worked out exactly how the American atomic bomb must have worked, judging from reports of the damage and explosive size, and gave a lecture to the rest of the captive scientists on the effort. While it is clear that Heisenberg had a firm understanding of the principles involved, he most likely greatly overestimated the amount of fissionable material required by several orders of magnitude. Heisenberg's 1941 meeting with Bohr In 1941, Werner Heisenberg met with his former mentor Niels Bohr in occupied Denmark and had a conversation outside of any other witnesses. The exact content of their conversation has, since the 1950s, been a matter of some controversy. The meeting and its controversy was the subject of a Tony Award-winning play from 1998 by Michael Frayn, Copenhagen. There is considerable speculation on what occurred at the real-life meeting, and the actual accounts of it from the parties involved differ. The pro-Bohr version of the story asserts that Heisenberg was seeking to recruit Bohr to the Nazi nuclear effort, and offering him academic advancement in return. The pro-Heisenberg version asserts that Heisenberg was attempting to give Bohr information about the state of the German atomic programme, in the hope that he might pass it to the Allies through clandestine contacts. At that point the German atomic programme was not progressing well (the Nazi government had decided not to undertake the investment required to develop a weapon during the war); Heisenberg may have suspected that the Allies had a viable atomic program, and hoped that by disabusing them of the idea that the German program was also successful he could dissuade the Allies from using an atom bomb on Germany. Much of the initial "controversy" resulted from a 1956 letter Heisenberg sent to the journalist Robert Jungk after reading the German edition of Jungk's book Brighter than a Thousand Suns (1956). In the letter, Heisenberg described his role in the German bomb project. Jungk published an extract from the letter in the Danish edition of the book in 1956 which, out of context, made it look as if Heisenberg was claiming to have purposely derailed the German bomb project on moral grounds. (The letter's whole text shows Heisenberg was careful not to claim this.) Bohr was outraged after reading this extract in his copy of the book, feeling that this was false and that the 1941 meeting had proven to him that Heisenberg was quite happy with producing nuclear weapons for Germany. After the play inspired numerous scholarly and media debates over the 1941 meeting, the Niels Bohr Archive in Copenhagen released to the public all heretofore sealed documents related to the meeting, a move intended mostly to settle historical arguments over what they contained. Among the documents were the original drafts of letters Bohr wrote to Heisenberg in 1957 about Jungk's book and other topics. The documents added little to the historical record but were interpreted by the media as supporting the "Bohr" version of the events. According to the archivists, the letters were released "to avoid undue speculation about the contents of the draft letter", which had been known about but not been open to historians previously. Analysis and Legacy There have been numerous other cited factors for the failure of the German program. One is that the repressive policies under Hitler encouraged many top scientists to flee Europe, including many who worked on the Allied project (Heisenberg himself was a target of party propaganda for some time during the Deutsche Physik movement). Another, put forth by ALSOS scientific head Samuel Goudsmit, was that the stifling, utilitarian political atmosphere adversely affected the quality of the science done. Another is that the German homeland was nowhere as secure from air attack as was the USA. Had the many massive centralized factories and production facilities constructed for the US bomb project been built in Germany, they would have been prime targets for Allied bombing raids. In 2005, Berlin historian Rainer Karlsch published a book, Hitlers Bombe (in German), which was reported in the press as claiming to provide evidence that Nazi Germany had tested crude nuclear weapons on Rügen island and near Ohrdruf, Thuringia, killing many war prisoners under the supervision of the SS. Some press reports, however, have reported the book as only having claimed to provide evidence that the Nazis have been successful with a radiological weapon (a "dirty bomb"), not a "true" nuclear weapon powered by nuclear fission. Karlsch's primary evidence, according to his publisher's reports, are "vouchers" for the "tests" and a patent for a plutonium weapon from 1941. Karlsch cites a witness to the Ohrdruf blast and another to the scorched bodies of victims afterwards. He also claims to have radioactive samples of soil from the sites. At the Nuremburg trials in 1946 Nazi munitions minister Albert Speer was questioned by prosecutors about the Ohrdruf blast, in an attempt to hold Speer accountable for its victims. Mainstream American historians have expressed skepticism towards any claims that Nazi Germany was in any way close to success at producing a true nuclear weapon, citing the copious amounts of evidence which seem to indicate the contrary. Others counter that Prof. Kurt Diebner had a project which was far more advanced than that of Dr. Werner Heisenberg. A recent article in Physics Today by the respected American historian Mark Walker has presented some of Karlsch's less controversial claims — that the Germans had done research on fusion, that they were aware that a bomb could potentially be made with plutonium, that they had engaged in some sort of test of some sort of device, that a patent on a plutonium device (of unspecified detail) had been filed and found — as substantiated. The Germans’ only source of heavy water, a necessary component of some of their bomb research, was Norsk Hydros plant in Vemork, Norway. In February 1943, a Norwegian commando unit sabotaged the plant. Whether this affected the German program is not clear. It is noteworthy, though, that Germany had already had a significant amount of heavy water and could have built a small reactor with it. The problem of the supply of uranium was solved in 1940 when over 1,000 tons of mixed uranium products were captured at Oolen in Belgium. Germany had everything ready, but just seemed unable to do anything with it.
It may or may not be significant that, since early spring, no accounts of research on nuclear fission have been heard from Germany — not even from discoverer Hahn. It is not unlikely that the German government, spotting a potentially powerful weapon of war, has imposed military secrecy on all recent German investigations. A large concentration of isotope 235, subjected to neutron bombardment, might conceivably blow up all London or Paris. New light on Hitler's bomb
Controversial new historical evidence suggests that German physicists built and tested a nuclear bomb during the Second World War. Rainer Karlsch and Mark Walker outline the findings and present a previously unpublished diagram of a German nuclear weapon This year marks the 60th anniversary of the American nuclear attack on the Japanese cities of Hiroshima and Nagasaki. The atomic bombs that were dropped on Japan in August 1945 were the fruit of a herculean wartime effort by the American, British and émigré scientists involved in the Manhattan Project. They had to overcome great obstacles and were only able to test their first atomic bomb after Germany surrendered in May of that year. The main motivation for these scientists when the project began in 1941 was the possibility that they were engaged in a race with their German counterparts to harness nuclear fission for war. Even Albert Einstein had been involved, signing a letter to President Roosevelt in 1939 urging that the US take nuclear weapons seriously. And in December 1943 the Danish physicist Niels Bohr visited Los Alamos - the home of the Manhattan Project - to offer both scientific and moral support. But when the war was over, it was clear that the Germans did not have atomic bombs like those used against Japan. The German "uranium project" - which had been set up in 1939 to investigate nuclear reactors, isotope separation and nuclear explosives - amounted to no more than a few dozen scientists scattered across the country. Many of them did not even devote all of their time to nuclear-weapons research. The Manhattan Project, in contrast, employed thousands of scientists, engineers and technicians, and cost several billion dollars. Not surprisingly, historians have concluded that Germany was not even close to building a working nuclear device. However, newly discovered historical material makes this story more complicated - and much more interesting. Germany and the bomb: a turbulent tale Our understanding of the German nuclear-weapons project during the Second World War has changed over time because important new sources of information keep turning up. For example, in 1992 the British government released transcripts of secretly recorded conversations between 10 German scientists who had been interned at Farm Hall near Cambridge in 1945. With the exception of Max van Laue, all the scientists - Erich Bagge, Kurt Diebner, Walther Gerlach, Otto Hahn, Paul Harteck, Werner Heisenberg, Horst Korsching, Carl Friedrich von Weizsäcker and Karl Wirtz - had been involved in the uranium project. What was most interesting was the surprise with which the scientists greeted the news that Hiroshima had been bombed. Ironically, at the end of the war German scientists had been convinced that they were ahead of the Allies in the race for nuclear energy and nuclear weapons. Further intriguing material appeared in 2002 when the Niels Bohr Archives in Copenhagen released drafts of letters that had been written by Bohr in the late 1950s about a visit to occupied Denmark by Heisenberg and von Weizsäcker in September 1941. After the war, the two German physicists claimed that they had merely gone to Copenhagen to assist Bohr and enlist his help in their efforts to forestall all nuclear weapons. But in the letters, Bohr denied that their actions or motivations had been so noble. The intrigue surrounding the visit has been well dramatized in Michael Frayn's play Copenhagen. We now have an extra twist to the tale with new documents that were recently discovered in Russian archives, including papers from the Kaiser Wilhelm Institute of Physics in Berlin. There are four particularly notable items among this material: an official report written by von Weizsäcker after a visit to Copenhagen in March 1941; a draft patent application written by von Weizsäcker sometime in 1941; a revised patent application in November of that year; and the text of a popular lecture given by Heisenberg in June 1942. One of us (RK) has used these documents - as well as many other sources - as the basis of a new book Hitlers Bombe. The book, which was published in March, prompted a heated debate about how close Germany was to acquiring nuclear weapons and how significant these weapons were (see Physics World April 2005 p7). Working with the journalist Heiko Petermann, RK discovered that a group of German scientists had carried out a hitherto-unknown nuclear-reactor experiment and tested some sort of a nuclear device in Thüringia, eastern Germany, in March 1945. According to eyewitness accounts given at the end of that month and two decades later, the test killed several hundred prisoners of war and concentration-camp inmates. Although it is not clear if the device worked as intended, it was designed to use nuclear fission and fusion reactions. It was, therefore, a nuclear weapon. Following the publication of Hitlers Bombe, another document has turned up from a private archive. Written immediately after the end of the war in Europe, the undated document contains the only known German drawing of a nuclear weapon. What did German scientists know? Over the years, several authors have concluded that Heisenberg and his colleagues did not understand how an atomic bomb would work. These authors include the physicist Samuel Goudsmit, who in 1947 published the results of a US Army investigation - entitled Alsos - into Germany's bomb effort. The historian Paul Lawrence Rose came to the same conclusion in his 1998 book Heisenberg and the Nazi Atomic Bomb Project 1939-1945. These critics argue that the German scientists did not understand the physics of a nuclear-fission chain reaction, in which fast neutrons emitted by a uranium-235 or plutonium nucleus trigger further fission reactions. Both Goudsmit and Rose also say the Germans failed to realize that plutonium can be a nuclear explosive. These criticisms of the Germans' scientific incompetence are apparently reinforced by the Farm Hall conversations, which reveal that Heisenberg initially responded to the news of Hiroshima with a flawed calculation of critical mass, although within a few days he had improved it and provided a very good estimate. However, there was other evidence that, no matter how Heisenberg responded at Farm Hall, he and his colleagues understood that atomic bombs would use fast-neutron chain reactions and that both plutonium and uranium-235 were fissionable materials. For example, in February 1942 the German army officials who were responsible for weapons development described the progress of the uranium project in a report entitled "Energy production from uranium". This overview, which was discovered in the 1980s, drew upon all classified material from Hahn, Harteck, Heisenberg and the other scientists working on the project. The report concluded that pure uranium-235 - which forms just 0.7% of natural uranium, the rest being non-fissionable uranium-238 - would be a nuclear explosive a million times more powerful than conventional explosives. It also argued that a nuclear reactor, once operating, could be used to make plutonium, which would be an explosive of comparable force. The critical mass of such a weapon would be "around 10-100 kg", which was comparable to the Allies' estimate from 6 November 1941 of 2-100 kg that is recorded in the official history of the Manhattan Project - the so-called Smyth report. Von Weizsäcker's draft patent application of 1941, which is perhaps the most surprising find from the new Russian documents, makes it crystal clear that he did indeed understand both the properties and the military applications of plutonium. "The production of element 94 [i.e. plutonium] in practically useful amounts is best done with the 'uranium machine' [nuclear reactor]," the application states. "It is especially advantageous - and this is the main benefit of the invention - that the element 94 thereby produced can easily be separated from uranium chemically." Von Weizsäcker also makes it clear that plutonium could be used in a powerful bomb. "With regard to energy per unit weight this explosive would be around ten million times greater than any other [existing explosive] and comparable only to pure uranium 235," he writes. Later in the patent application, he describes a "process for the explosive production of energy from the fission of element 94, whereby element 94...is brought together in such amounts in one place, for example a bomb, so that the overwhelming majority of neutrons produced by fission excite new fissions and do not leave the substance". This is nothing less than a patent claim on a plutonium bomb On 3 November 1941 the patent application was resubmitted with the same title: "Technical extraction of energy, production of neutrons, and manufacture of new elements by the fission of uranium or related heavier elements". This submission differed in two significant ways. First, the patent was now filed on behalf of the entire Kaiser Wilhelm Institute, instead of just von Weizsäcker. Second, every mention of nuclear explosive or bomb had been removed. The removal of any reference to weapons could reflect the change of fortunes in the Second World War: in November 1941 a quick German victory no longer appeared as certain as it had done earlier in the year. Another possible explanation is that von Weizsäcker and his colleagues had a change of heart - perhaps their initial enthusiasm for the military applications of nuclear fission had cooled. This would support Heisenberg's and von Weizsäcker's post-war claims that they had visited Bohr in September 1941 because they were ambivalent about working on nuclear weapons. Perhaps the most forceful exponent of this thesis is Thomas Powers in his 1993 book Heisenberg's War. But another of the new Russian documents - von Weizsäcker's report on his visit to Copenhagen in spring 1941 - suggests that, at least at that time, he was enthusiastic about the uranium work. Indeed, we know that, after the war, scientists from Bohr's institute accused Heisenberg and von Weizsäcker of acting as German spies when they came to Copenhagen. There may at least be some truth to this because in March 1941, when Germany had not yet invaded the Soviet Union and victory appeared likely, von Weizsäcker reported the following to the Army. "The technical extraction of energy from uranium fission is not being worked on in Copenhagen. They know that in America Fermi has started research into these questions in particular; however, no more news has arrived since the beginning of the war. Obviously Professor Bohr does not know that we are working on these questions; of course, I encouraged him in this belief...The American journal Physical Review was complete in Copenhagen up to the January 15, 1941 issue. I have brought back photocopies of the most important papers. We arranged that the German Embassy will regularly photocopy [make photographs of] the issues for us." The spotlight turns to Diebner RK's book Hitlers Bombe draws upon what was already known about the German wartime work on nuclear reactors and isotope separation, and uses documents from Russian archives, oral history and industrial archaeology to open up a new chapter in the history of German nuclear weapons. For most of the war, there were two competing groups working on nuclear reactors: a team under the Army physicist Kurt Diebner in Gottow near Berlin; and scientists directed by Werner Heisenberg in Leipzig and Berlin. Whereas the experiments under Heisenberg used alternating layers of uranium and moderator, Diebner's team developed a superior 3D lattice of uranium cubes embedded in moderator. Heisenberg never gave Diebner and the scientists working under him the credit they were due, but the Nobel laureate did take up Diebner's design for the last experiment carried out in Haigerloch in south-west Germany. RK now reveals that Diebner managed to carry out one last experiment in the last months of the war. The exact details of the experiment are unclear. After a series of measurements had been taken, Diebner wrote a short letter to Heisenberg on 10 November 1944 that informed him of the experiment and hinted that there had been problems with the reactor. Unfortunately, no more written sources have been found relating to this final reactor experiment in Gottow. Industrial archaeology done at the site during 2002 and 2003 suggests that this reactor sustained a chain reaction - if only for a short period of time - and may have ended in an accident. In 1955 Diebner submitted a patent application for a new type of "two-stage" reactor that could breed plutonium. An internal section would use enriched uranium to achieve a self-sustaining chain reaction, while a much larger external section would surround the internal reactor and run at a subcritical level. Plutonium could then be removed from internal section. It appears likely that Diebner's 1955 patent application drew upon his last wartime experiment. More surprising, if not shocking, is another revelation in RK's book: a group of scientists under Diebner built and tested a nuclear weapon with the strong support of both Walther Gerlach - an experimental nuclear physicist who by 1944 was in charge of the uranium project for the Reich Research Council. (Hahn, Heisenberg, von Weizsäcker and most of the better-known scientists in the uranium project apparently were not informed about this weapon.) This device was designed to use fission reactions, but it was not an "atomic" bomb like the weapons used against Nagasaki and Hiroshima (figures 1a and b). And although it was also designed to exploit fusion reactions, it was nothing like the "hydrogen" bombs tested by the US and the Soviet Union in the 1950s. Instead, conventional high explosives were formed into a hollow shape, rather than a solid mass, to focus the energy and heat from the explosion to one point inside the shell (figure 1c). Small amounts of enriched uranium, as well as a source of neutrons, were combined with a deuterium-lithium mixture inside the shell. This weapon would have been more of a tactical than a strategic weapon, and could not have won the war for Hitler in any case. It is not clear how successful this design was and whether fission and fusion reactions were provoked. But what is important is the revelation that a small group of scientists working in the last desperate months of the war were trying to do this. Blueprint for a bomb
The diagram is schematic and is far removed from a practical blueprint for an atomic bomb Although the weapon is shown to be a fission device based on plutonium, the report also reveals that German scientists had worked intensively on the theory of a hydrogen bomb What the report does demonstrate is that the knowledge that uranium could be used to make powerful new weapons was fairly widespread in the German technical community during the war, and it contains the only known German diagram of a nuclear weapon. This diagram is schematic and is far removed from a practical blueprint for an "atomic bomb". The unknown author also mentions a critical mass of slightly more than 5 kg for a plutonium bomb. This estimate is fairly accurate, because the use of a tamper to reflect neutrons back into the plutonium would cut the critical mass by a factor of two. Moreover, this estimate is particularly significant because such detailed information was not included in the Smyth report. The new report is also interesting because it makes clear that German scientists had worked intensively on theoretical questions concerned with the construction of a hydrogen bomb. Two additional sources confirm this. The papers of Erich Schumann, director of the Army's weapons-research department, include many documents and theoretical calculations of nuclear fusion. The Viennese physicist Hans Thirring also discussed this topic in his book The History of the Atomic Bomb, which was published in the summer of 1946. Not the last word Historians, scientists and others have debated for decades whether Heisenberg and von Weizsäcker wanted to build atomic bombs.Taken together, the new revelations change our picture of German nuclear weapons. None of this new information supports in any way either the interpretation of Heisenberg and his colleagues as resistance fighters (Powers) or as incompetents with Nazi sympathies (Rose). However, these new documents and RK's revelations do place Heisenberg and von Weizsäcker in a different context by making their ambivalence about nuclear weapons much clearer. Although they continued to work on nuclear reactors and isotope separation, and dangled the prospect of nuclear weapons in front of powerful men in the Nazi state, they did not try as hard as they could to create nuclear weapons for Hitler's regime. Other scientists were doing that, notably Walther Gerlach,Kurt Diebner and the researchers working under him. It would be rash indeed to believe that this is the last word on the matter. The German atomic bomb is like a zombie: just when we think we know what happened, how and why, it rises again from the dead. Heisenberg's role During the Second World War, Werner Heisenberg was one of the most influential scientists in Germany and its leading theoretical physicist. He had won a Nobel prize for his work on quantum mechanics and the uncertainty principle, had become one of the youngest full professors in Germany when he began teaching at the University of Leipzig, and in 1942 at the age of 40 was appointed director of the prestigious Kaiser Wilhelm Institute for Physics as well as professor at the University of Berlin. However, in the early years of the Third Reich, Heisenberg had been attacked by his fellow Nobel laureate Johannes Stark in an SS publication for being a "white Jew" and "Jewish in spirit". A subsequent investigation by the SS ended in 1939 with his public and political rehabilitation. The result was that, by 1942, Heisenberg enjoyed the support of influential figures in the Nazi regime, including the armaments minister Albert Speer, as well as the industrialist Albert Vögler, who was president of the Kaiser Wilhelm Society. Pulled both ways In February 1942 Heisenberg gave a popular lecture to an influential audience of politicians, bureaucrats, military officers and industrialists. At the time, the future of Germany's uranium project was in doubt because the Army was only interested in weapons that could be delivered in time to influence the outcome of the war. As we know from a transcript of the talk, which was discovered by the historian David Irving in the 1960s, Heisenberg emphasized both the potential of nuclear weapons and how difficult it would be to make them. His conclusion was clear. 1) Energy generation from uranium fission is undoubtedly possible, provided the enrichment of isotope uranium-235 is successful. Isolating uranium-235 would lead to an explosive of unimaginable potency. 2) Common uranium can also be exploited to generate energy when layered with heavy water. In a layered arrangement these materials can transfer their great energy reserves over a period of time to a heat-engine. It thus provides a means of storing very large amounts of energy that are technically measurable in relatively small quantities of substances. Once in operation, the machine can also lead to the production of an incredibly powerful explosive. However, by the summer of 1942, the uranium project had been transferred from the German Army to the civilian Reich Research Council and the German uranium-project scientists once again enjoyed secure institutional support. In June of that year Heisenberg gave a lecture at the Kaiser Wilhelm Society in Berlin before Speer and other military and industrial leaders of the Nazi state. The lecture has become famous because of the story that Heisenberg responded to a question about the size of an atomic bomb by saying that it would be about as big as a pineapple. This anecdote was first reported in Irving's 1968 book The Virus House, but a transcript of the talk had never been found. However, it has now been discovered in the new Russian documents. The text of the June lecture - entitled "The work on uranium problems" - differs significantly from the February talk. Heisenberg begins by mentioning the discovery of nuclear fission in 1939, noting that interest in this new development had been "exceptionally great", especially in the US. "A few days after the discovery," he notes, "American radio provided extensive reports and half a year later a large number of scientific papers had appeared on this subject." Heisenberg continues by describing Germany's work on isotope separation and nuclear reactors since the start of the war, cautioning that "naturally a series of scientific and practical problems will have to be cleared up before the technical goals can be realized". Mid-way through the talk, Heisenberg makes his only mention of nuclear weapons in a rather understated way. "Given the positive results achieved up until now," he says, "it does not appear impossible that, once an uranium burner has been constructed, we will one day be able to follow the path revealed by von Weizsäcker to explosives that are more than a million times more effective that those currently available." But even if that did not happen, the nuclear reactor would have an "almost unlimited field of technical applications". These include boats and even planes that could travel long distances on small amounts of fuel, as well as new radioactive substances that could be useful for many scientific and technical problems. Heisenberg concludes by saying that new discoveries of "the greatest significance for technology" will be made "in the next few years". Since the Germans knew that "many of the best laboratories" in America were working on this problem, they could hardly afford "not to follow these questions", Heisenberg points out. Even if "most such developments take a long time", they had to reckon with the possibility that - if the "war with America lasted for several years" - the "technical realization of atomic nuclear energies" might "play a decisive role in the war". Heisenberg was right about that, of course. But fortunately for him and his countrymen, the first atomic bombs fell on Hiroshima and Nagasaki instead of Frankfurt and Berlin. A timeline to the bomb
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In March and April of 1945, US General George S. Patton and his Third Army were not racing towards Berlin, but across southern Bavaria. They were, claims author Joseph P. Farrell, in his book, Reich of the Black Sun, making haste towards (1) the huge Skoda munitions works at Pilsen; (2) Prague; and (3) a region of the Harz Mountains in Thuringia. Supposedly the maneuver was meant to stymie any attempted Nazi last stand in their Alpine National Redoubt, a series of fortified mountains stretching from the Alps to the Harz Mountains. The true reason for Patton's haste, however, was to prevent Germany from exploding an atomic bomb. Deep within his embattled Führerbunker in Berlin, Adolf Hitler had boasted that Germany was on the verge of using weapons that would win the war for them at "five minutes past midnight." "The desperate ravings of a lunatic" is history's too pat answer to Hitler's intriguing claim. Yet Farrell, Nick Cook (author of The Hunt For Zero Point), and others have argued that the Nazis indeed had developed amazing technologies. Not only did General Patton and his Third Army stop an atomic nightmare, they also secured the evidence of Germany's secret scientific advances based upon bizarre physics
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Alsos was an effort at the end of World War II by the Allies (principally Britain and the United States), branched off from the Manhattan Project, to investigate the German nuclear energy project, seize German nuclear resources, materials and personnel to further American research and to prevent their capture by the Soviets, and to discern how far the Germans had gone towards creating an atomic bomb. The personnel of the project followed close behind the front lines, first into Italy, and then into France and Germany, searching for personnel, records, material, and sites involved. Alsos is sometimes mistakenly written ALSOS by sources including the U.S. Army, perhaps because it does not look like a usual English word and is thus falsely assumed to be an acronym. In fact, Alsos is Greek for "grove", and so this designation is a play on the name of Major General Leslie M. Groves, the military director of the Manhattan Engineer District (the Manhattan Project), the Allied wartime effort to develop an atomic bomb (which itself was sparked out of fears of a German weapon). Groves was the major impetus behind the project, in part because of his desire to make sure that German technology and personnel did not fall into Soviet hands, so as to prolong the anticipated American monopoly on nuclear weapons as long as possible. Samuel Goudsmit was the technical/scientific leader of Alsos, and Lt. Col. Boris Pash, a former Manhattan Project security officer, was its military leader. Major league baseball player, attorney, and linguist, Moe Berg contributed in various phases. The project managed to find and remove many of the German research effort's personnel and a good bit of the surviving records and equipment. Most of the senior research personnel (including Werner Heisenberg, Otto Hahn, and Carl Friedrich von Weizsäcker) were sequestered at Farm Hall in England for several months. Their discussions were secretly taped, and transcripts of those tapes have been released. In the end, Alsos concluded that the Allies had surpassed the German atomic bomb effort monumentally by 1942. Compared to the Manhattan Project, one of the largest scientific endeavors of all time, the German project was considerably underfunded and understaffed, and it is questionable whether Germany would have had the resources or isolation which were required for the Allies to produce such a weapon. Goudsmit, in a monograph published two years after the end of the war, further concluded that a principal reason for the failure of the German project was that science could not flourish under totalitarianism — an argument seemingly rebutted by the German advances on other technologies, such as world’s first jet fighter Messerschmitt Me 262, first stealth fighter-bomber Horten Ho 229, first ballistic missile V-2 and Soviet Union's development of a nuclear weapon by 1949. The Soviets, however, benefited from Stalin's extensive spy network, which included at least two well-informed scientists at Los Alamos, Klaus Fuchs and Theodore Hall. Both worked to prevent the United States from holding a nuclear monopoly over the world.
Operation Big was a part of the overarching Allied effort (called Operation Alsos) to capture German nuclear secrets during the final days of World War II. In this portion of the operation, nuclear intelligence teams moved quickly from Freudenstadt through Horb to Haigerloch in southwest Germany. Troops taking part in this operation (dubbed "Task Force A") captured a German atomic pile at Haigerloch that only needed additional heavy water to become operational. Nearby at Hechingen they uncovered the heavy water plant shipped from Norway after the Operation Freshman and Operation Gunnerside attacks. The operation was conducted in April 1945.
Harborage teams were directed toward the cities of Hechingen, Bisingen and Haigerloch. These centers of the German nuclear effort were all scheduled to be occupied by the French. By ensuring American technical intelligence units swept the area, the French were locked out of the lively post-war trade in nuclear scientists. |
