Atomic
Jim Baggott
ISBN: 9781848310827
The first fully realised popular account of the race between Nazi Germany, Britain, America and the Soviet Union to build atomic weapons.
Drawing on declassified material such as MI6âs Farm Hall transcripts, coded Soviet messages cracked by American cryptographers and interpretations by Russian scholars of documents from the Soviet archive, Jim Baggottâs monumental book spans ten historic years, from the discovery of nuclear fission in 1939 to âJoe-1â, the first Soviet atomic bomb test in August 1949.
It includes dramatic episodes such as the sabotage of the Vemork heavy water plant by Norwegian commandos and the infamous meeting between Niels Bohr and Werner Heisenberg, the subject of Michael Fraynâs stage play Copenhagen.
Baggott also tells of how Allied scientists were directly involved in the hunt for their German counterparts in war-torn Europe following D-Day; and brings to light the reactions of captured German scientists on hearing of the Allied success at Hiroshima.
Atomic is an epic story of science and technology at the very limits of human understanding; a tale barely believable as fiction, which just happens to be historical fact.
Chapter 10
Escape from Copenhagen
JanuaryâNovember 1943
Despite receiving numerous invitations to visit America shortly after the Nazi occupation of Denmark, Niels Bohr had nevertheless decided it was his duty to remain. He wanted to do what he could to preserve the scientific institutions which he had helped to build, and the scientists who worked within them. And, indeed, the work did continue. Bohr and his team had access to a cyclotron and high-tension apparatus suitable for fission experiments. The lack of materials, especially metals, was alleviated somewhat by the Carlsberg Foundation, a generous sponsor of Denmarkâs greatest physicist, which loaned Bohrâs institute a supply of metals from the Carlsberg brewery. Bohr probably thought he could sit out the war if not in comfort or free of concern, then at least in relative peace.
Eric Welsh thought rather differently. The veteran British SIS operative had figured that Bohr would be a valuable addition to Tube Alloys. Late in 1942 Tronstad had received a message indicating that Bohr would welcome the opportunity to see him again â interpreted as a hint that Bohr was ready to leave Denmark. Welsh talked to âCâ, Sir Stewart Menzies, the head of the SIS, and they agreed that an approach to Bohr should be made to sound him out about coming to Britain.
Shortly afterwards, in January 1943, Chadwick was approached by the SIS in Liverpool and asked if he would draft a letter of invitation to Bohr. Once the details of the proposed escape, or âex-filtrationâ plan had been explained, Chadwick agreed. His letter, dated 25 January, offered a warm welcome should Bohr decide to leave Denmark, freedom to work on any scientific problems of interest, and a veiled request for Bohrâs support on the atomic programme. âIndeed I have in mind a particular problem in which your assistance would be of the greatest helpâ, he wrote.
The letter was reduced to a microdot and smuggled to Bohr hidden in the hollow handle of a key, stored on a ring alongside a number of other keys. A second key on the ring contained a duplicate microdot. Bohr was alerted to the imminent arrival of the message by Captain Volmer Gyth, an officer in the information division of the Danish general staff with connections to the Danish resistance. Gyth passed him a set of instructions to the effect that: âProfessor Bohr should gently file the keys at the point indicated until the hole appears. The message can then be syringed or floated out onto a microscope slide ⌠It should be handled very delicately.â Perhaps somewhat uncertain of his own abilities in the tradecraft of a spy, when Gyth offered to recover the microdot and provide him with a written version of the letter, Bohr gratefully accepted.
Bohrâs judgement of the situation was, however, unchanged. His desire was to remain in Denmark and continue his work at the institute. As far as he understood, the possibility of extracting U-235 from natural uranium in sufficient quantities to make a bomb was completely impractical. He gave his reasons in a reply but he also left open the possibility of coming to Britain, recognising that his circumstances could easily change. âHowever,â he wrote, âthere may, and perhaps in a near future, come a moment where things look different and where I, if not in other ways, might be able modestly to assist in the restoration of international collaboration in human progress.â Gyth reduced Bohrâs letter to millimetre dimensions, wrapped it in foil and arranged to have it inserted in the hollow tooth of a courier, hidden beneath a filling.
Further correspondence ensued, though the manner of transmission of subsequent messages was rather more conventional. Bohr explained in more detail why he thought a fission bomb was impossible.
Separate ways
After successfully completing their sabotage mission, the Norwegian commandos of Swallow and Gunnerside went separate ways, as Falkenhorst and Reichskommisar Josef Terboven ordered a massive search. Rønneberg led Idland, Kayser, Strømsheim and Storhaug north towards the Swedish border. They arrived on Swedish soil fifteen days later, exhausted from a 250-mile trek that had not been without incident but which had been relatively straightforward. On reaching London they were greeted warmly and given a nice cup of tea.
Poulsson and Helberg headed for Oslo, intending to lay low for a while before making contact with the Norwegian underground. From Oslo, Poulsson escaped into Sweden before returning to Britain for a short while. Helberg, who had done time in a Swedish prison and was therefore known to the authorities, planned to head back to the Hardanger Plateau when the dust had settled. Acting on incorrect advice, on 25 March 1943 he arrived back in an area that was still crawling with German troops. Realising he had been spotted, he set off on skis as three German soldiers gave chase. Two gave up after an hour. After two hours, Helberg turned and faced his pursuer. The German emptied his Luger, missing with every shot. Now it was Helbergâs turn. He gave chase, bringing the German down with a single shot from his Colt .32.
More adventures were to follow. In darkness, Helberg fell over a precipice and broke his left shoulder. He reached his destination, a house he knew in the village of Rauland, only to find it full of German troops. He bluffed his way through the next two nights, drinking and playing cards with the troops, and even managed to get medical attention for his shoulder. He moved to a hotel in Dalen, where he was unfortunate to get caught up in an altercation between Terboven, who was staying in the next room, and a young, attractive Norwegian woman who had spurned Terbovenâs amorous advances. Helberg was rounded up with the other Norwegians in the hotel on the orders of a now incensed Terboven, and was told they were all to be sent to Grini concentration camp. Helberg jumped from the bus on the way to Oslo, avoiding grenades and pistol shots. He eventually managed to get to Sweden, avoided imprisonment, and boarded a plane bound for Britain on 2 June.
Haugland and Skinnarland moved their makeshift wireless operation to a location high in the mountains. They took cover under the snow and watched the German troops make a mess of the search on the Hardanger Plateau. Haugland completed Skinnarlandâs wireless training before joining his brother, whom he was surprised to find leading the resistance in Oslo. He provided the resistance with further SOE-style training in the use of explosives.
Haukelid and Kjelstrup headed west on the Hardanger Plateau, where they stayed for much of the summer of 1943. Kjelstrupâs health began to suffer, and he returned to Britain to recuperate.
Somewhat improved apparatus
The loss of heavy water production from the Vemork plant was a major setback to the German programme. The loss was to prove temporary, however. Tronstad and Brun had believed that the destruction of the high concentration cells would halt production for a few years. But the damage was already repaired by 17 April 1943, and the plant was again producing small quantities of heavy water by the end of June.
By this time, the German War Office had ceased to take any interest in the programme. Diebner and his research team were transferred back to the broader Uranverein under the auspices of the Reich Research Council, although the team was allowed to continue working at the Army Ordnance laboratory in Gottow. The two million Reichsmarks that had been promised by the War Office never materialised, and the Reich Research Council was left with the task of finding the money for itself. Speer remained an enthusiastic patron, however, and adequate funding was forthcoming.
Diebner may not have been a leading light in German theoretical physics, but he was an accomplished experimentalist. The reactor experiments that had been carried out so far under Heisenbergâs overall guidance had relied on configurations in which uranium metal plates and quantities of the heavy water moderator were organised in layers. Diebner had devised an alternative configuration based on a three-dimensional lattice of equally spaced cubes of uranium oxide or uranium metal immersed in a volume of moderator. Ingeniously, he further figured that he could do without an enveloping container of aluminium by freezing the heavy water moderator solid. In effect, the âheavy iceâ would function both as moderator and support structure.
He set up such a configuration in the low-temperature laboratory of the Reich Institute for Technical Chemistry. Reactor G-II consisted of about 230 kilos of uranium in the form of cubes and 210 kilos of heavy ice, arranged in a sphere about 75 centimetres in diameter. No self-sustaining chain reaction was generated but there was clear evidence for neutron multiplication, about one and a half times greater than the corresponding neutron multiplication in L-IV. Diebner was convinced that a self-sustaining chain reaction would be achieved with sufficient uranium and heavy water.
Heisenberg, however, made light of Diebnerâs achievements. In a conference held in Berlin on 6 May he acknowledged the results from Diebnerâs group but declared that the latterâs âsomewhat improved apparatusâ had âyielded the same resultâ as the previous yearâs L-IV design. Heisenberg was planning a large-scale reactor experiment and had no intention of moving away from the layer configuration.
Subsequent experiments at the Gottow laboratory bore out Diebnerâs conviction. The team repeated the uraniumâheavy ice experiment with the same quantities of materials but this time with a lattice of uranium cubes suspended on fine alloy wires in a volume of liquid heavy water at normal laboratory temperatures. A further experiment with over 560 kilos of uranium and nearly 600 kilos of heavy water yielded even more promising results. It was clear that the lattice design was superior to anything that had yet been produced in Berlin or Leipzig.
Diebner started to draw up plans for an even larger reactor, but now ran into conflict with the demands of Heisenbergâs experiments. Heisenberg preferred to continue with the layer configuration despite the evidence suggesting that the lattice arrangement might work better. At issue here was the very different experimental philosophies adopted by the two research groups. Heisenberg was content to build understanding of the physics through a series of reactor experiments designed to allow measurement of the values of fundamental nuclear constants. As Heisenberg later confided to Harteck, he preferred the layer configuration because the theory was much simpler.
Diebner was less concerned about the theory and wanted to build a working reactor as quickly as possible. When subsequent theoretical studies pointed to the superiority of Diebnerâs lattice configuration, Heisenberg remained stubborn. Professional pride may have been a factor, but the simple truth was that for Heisenberg the nuclear project was no longer his major preoccupation.
More ominously, perhaps, Heisenberg had so far perceived no need for cadmium control rods of the kind that had been used in the Chicago uraniumÂâgraphite pile, although he understood that these would be required in a working reactor. In truth, without control rods an experimental nuclear reactor reaching criticality would precipitate a major disasterÂ.
A lot of experience in microfilm work
âOh, I think that is trueâ, Oppenheimer said, in answer to Pashâs question concerning other groups interested in the work going on at the Rad Lab. âBut,â he went on to say, âI have no firsthand knowledge. I think it is true that a man, whose name I never heard, who was attached to the Soviet consul, has indicated indirectly through intermediary people concerned in this project that he was in a position to transmit, without danger of leak, or scandal, or anything of that kind, information which they might supply.â
Oppenheimer explained that, speaking frankly, he was âfriendlyâ to the idea that the Russians â as allies of America in the war against Nazi Germany â be advised of the American work on the atomic bomb, but that he would not want this kind of information to get to the Soviets through the âback doorâ.
Pash was all ears.
âCould you give me a little more specific information as to exactly what information you have?â Pash enquired. âYou can readily realise that phase would be, to me, as interesting, pretty near, as the whole project is to you.â
âWell, I might say,â replied Oppenheimer, âthat the approaches were always to other people, who were troubled by them, and sometimes came and discussed them with me.â He went on: â[T]o give more ⌠than one name would be to implicate people whose attitude was one of bewilderment rather than one of co-operation.â
In Oppenheimerâs reply, the Chevalier incident had suddenly become one of several approaches, to several physicists working on the programme. Two of these physicists, Oppenheimer explained, were working with him at Los Alamos, and the other was a Rad Lab physicist who had departed, or was about to, for the Oak Ridge facility in Tennessee. It was, as he later admitted, a âcock and bull storyâ, designed â if Oppenheimerâs flustered response could be called that â to throw Pash off the scent.
Oppenheimer had already named Eltenton, who, he now explained, was to arrange contact with someone from the Soviet consulate âwho had a lot of experience in microfilm work, or whatever the hellâ. But Oppenheimer did not want to name Chevalier, who he believed had acted as an innocent messenger. When pressed by Pash to name his friend, Oppenheimer replied: âI think it w...
