MAUD & TUBE ALLOYS

See Also: NUCLEAR WEAPONS; NUCLEAR WEAPONS Chain Reaction; AN OLE IN OLBORN; THE SECOND WORLD WAR The Scientists

In 1933 the Nazis seized control of the German state. The German-born physicist Otto Frisch went into exile. After a spell of working with Patrick Blackett at Birkbeck College, he took up a position with Niels Bohr in Copenhagen.

Mark Oliphant was an Australian-born physicist who had worked under Lord Rutherford at the Cavendish Laboratory in Cambridge. The former had concluded that heavy hydrogen might be a potential source of power, the latter held the idea to be fanciful. Oliphant judged that the time had come for him to move on. In 1936 he was appointed to a chair in physics at Birmingham University. The following year he engineered the appointment of the German exile Rudolf Peierls as one of his colleagues.

In late 1938, in Germany, Otto Hahn and Friedrich Strassmann collided a neutron and a uranium nucleus. One of the resulting products that they identified was barium. They appreciated that this meant that they had split the atom. However, they did not understand the physics of how it had happened. Frisch heard news of the experiment while he was in Stockholm visiting his aunt Lise Meitner, who was a noted physicist. The pair worked out an explanation for what had occurred. They appreciated the nucleus's excessive electric charge and were able to calculate how much energy had been released. Frisch dubbed the process fission . Physicists around the world soon appreciated that the phenomenon opened up the prospect of a man-induced chain reaction.

British involvement in the Second World War commenced on 3 September 1939. At the time, Frisch was visiting Peierls in Birmingham. The start of the conflict meant that he was unable to return to Denmark, therefore, he stayed on. The prevailing academic approach to fission ignored the possibility of its being a fast-neutron process because, with uranium-238, such was taken to be impractical. Frisch was open to the idea of using uranium-235 instead. The pair worked out that, if the isotope could be extracted from uranium-238, the total amount that would be needed to create a chain reaction would be only a single kilogram. In March 1940 they wrote down their conclusions in a memorandum. This they gave to Oliphant who appreciated that it opened a realistic path towards the development of a nuclear bomb. His involvement in how the technology of radio location could be improved meant that he had already had dealings with Henry Tizard, the chairman of the Air Ministry's Committee for the Scientific Survey of Air Warfare. Upon receiving the memorandum, the Committee set up the Maud Committee to assess whether Britain could develop an atomic weapon.¹ This new body was chaired by George Thomson of Imperial College. He had failed to consider fast-neutron fission and so was able to appreciate the adroitness of two exiles insight.

In June 1941 the Maud Committee issued its findings. The principal author of its report was James Chadwick of Liverpool University. The two-part document concluded that a British atomic bomb could be built by 1943. Patrick Blackett of the University of Manchester was the only member of the Committee to dissent from this view. He declared that the work should not be undertaken by Britain alone but that instead it should be done in partnership with the United States. The Frisch-Peierls memorandum and the Maud report were communicated to the United States's Briggs Advisory Committee on Uranium.

The project to develop a British-made nuclear weapon was overseen by the Department of Scientific & Industrial Research. The scheme was named Tube Alloys in an attempt to conceal the true character of what was being done. The chemical company ICI was informed that Britain was going to develop an atomic bomb. The firm made a bid to run the whole project. This was rebuffed. However, the ICI executive Wallace Akers, a physical chemist by education, was identified as having the potential to manage the undertaking.² He was recruited as a temporary civil servant and appointed as the Director of Tube Alloys. His new colleagues included Chadwick.

When Tube Alloys was set up most British- and Empire-born physicists were already deeply engaged in war-related work. This created the paradox that a high proportion of those who were recruited to work on the development of the most lethal weapon ever created had been born and educated in Germany. Working closely together, the Berliners, Peierls and Francis Simon concluded that the most effective way to separate uranium-235 from natural uranium would be by gaseous diffusion.³ However, this would require a large industrial facility. Even if such a plant could be built in Britain in the prevailing conditions, it would be nigh on impossible to operate it once the Luftwaffe had concluded that such a large new undertaking must be something of strategic importance. The logic of this finding was that, if the bomb was to be built in the shortest time possible, then, it would have to be made outside of the United Kingdom.

The Americans had not made any substantive response to either the Frisch-Peierls memorandum or the Maud report. In August 1941 Oliphant visited the United States on radio location business. He learned that Lyman J. Briggs, upon receiving the papers, had placed them in a safe and had not communicated their substance to any of his colleagues. The Australian conducted a series of meetings with the likes of Arthur Compton, James Bryant Conant, and Ernest Lawrence to inform them of the memorandum, what Maud had concluded, and what had been done since. His audience was receptive and made it their business to initiate an American atomic weapons programme. On the day before Pearl Harbour was attacked, the United States government committed itself to developing a nuclear bomb.

That Akers had a background as a senior executive within one of Britain's principal companies made him an object of suspicion to the Americans. They swiftly came to the view that the United Kingdom was planning to maximise its economic benefit from the new technology. General Leslie Groves, the head of the Manhattan Project, refused to have any dealings with the man. In summer 1942 the United States Army chose to block the flow of information to the British about its development of a nuclear weapon. This development was not known of at the highest governmental levels.

Eventually Winston Churchill and Franklin both became aware that Anglo-American co-operation on the construction of an atomic bomb had stopped almost as soon as it had started. The Quebec Agreement of summer 1943 restarted the process. Chadwick was appointed to liaise with the Americans. He proved to be able to win Groves's full confidence and became with him one of only three people to have a full knowledge of the Manhattan Project. There was a major inflow of British scientists into its Los Alamos Laboratory.⁴

Website: www.lanl.gov (Los Alamos National Laboratory)

¹. The name Maud was intended to mask the subject that the committee was assessing.

². Some within the Civil Service were of the belief that it had been Akers who had induced I.C.I. to make its audacious bid.

³. Peierls used Klaus Fuchs as an assistant to handle some of the calculations. (Fuchs had been born in R sselsheim.)

⁴. Included in the number, at Peierl's insistence, was Fuchs. In 1950 the by then deputy chief scientific officer at Atomic Energy Research Establishment's facility at Harwell in Oxfordshire was arrested for espionage. He was tried, found guilty, and served a nine-year prison sentence.

David Backhouse 2024