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The Maud Committee (Military Application of Uranium Detonation) was the beginning of the British atomic bomb project, before the United Kingdom joined forces with the United States in the Manhattan Project. It prompted the USA to begin its own atomic bomb project.
Frisch and Peierls
In February 1940, Otto Frisch and Rudolf Peierls, working at the University of Birmingham in the UK, considered the possibility of fast fission in uranium-235. They estimated the critical mass of pure U-235 was only "a pound or two", and that much of this mass would react before the rest was blown away by the explosion. They estimated the likely effects of the bomb, possible methods of assembly and made estimates on how feasible it was to separate the uranium-235. They prepared a memorandum, the Frisch–Peierls memorandum, on their discovery and gave a copy to their professor, Marcus Oliphant, who passed it to Henry Tizard, the chairman of the Committee on the Scientific Survey of Air Defence, which was the most important scientific committee for defense in Britain.
At Tizard's behest, the Maud Committee first met on 10 April 1940 to consider Britain's actions regarding the "uranium problem". A research programme on isotope separation and fast fission was agreed upon. In June 1940 Franz Simon was commissioned to research on isotope separation through gaseous diffusion. Ralph H. Fowler was also asked to send the progress reports to Lyman Briggs in America from that date.
There are differing theories on how the Maud Committee acquired its code name in July 1941. One theory is that MAUD stands for Military Applications of Uranium Detonation. Another story has it that there was actually no acronym behind the name, but that it arose from a misunderstanding of a telegram sent to England by Lise Meitner with news from Niels Bohr, and to "Please inform Cockcroft and Maud Ray Kent." Thomson, deciding that "maud ray kent" was an anagram for "radium taken," borrowed the word MAUD to name his committee in an enigmatic way. In reality, Maud Ray was an English governess from Kent who had taught Bohr's sons English. 
The MAUD Committee consisted of:
- Sir George Paget Thomson, Chairman
- Marcus Oliphant
- Patrick Blackett
- James Chadwick
- Philip Moon
- John Cockcroft
Although the original work had been done by Frisch and Peierls, one was German, one was Austrian and so were "officially" classified as "enemy aliens" and could not be a part of a wartime committee. (Later they both made significant contributions at Los Alamos as part of the British Mission.)
Franz Simon completed his work on isotopic separation in December 1940, concluding that it was possible. This included cost estimates and technical specifications for a large uranium enrichment plant. James Chadwick, author of the report's final draft, later wrote that at that time he "realised that a nuclear bomb was not only possible, it was inevitable. I had then to start taking sleeping pills. It was the only remedy."
In March 1941 the Department of Terrestrial Magnetism (DTM) at the Carnegie Institution measured the fast cross-section of U-235. Using it, Peierls calculated a new critical mass for U-235 at 18 pounds as a bare sphere, or 9–10 pounds when surrounded by a reflector. A report was produced in the same month by the Maud Committee, describing the importance of fast fission for bomb design and a copy was sent to the Uranium Committee in the USA. The secretary of the committee, Lyman Briggs, locked up the document on arrival in March 1941 and showed it to no one.
The Maud Report dismissed plutonium production, thermal diffusion, the electromagnetic method, and the centrifuge and recommended gaseous diffusion of uranium-235 on a massive scale. The British believed that uranium research could lead to the production of a bomb in time to affect the outcome of the war. While the Maud Report was supposed to provide encouragement to Americans by advocating a larger uranium research programme, it also served as a sobering reminder that fission had been discovered in Nazi Germany almost three years earlier, and that, since the spring of 1940, a large part of the Kaiser Wilhelm Institute in Berlin had been set aside for uranium research.
Chadwick's final draft, July 1941; telling the USA
After months of growing pressure from scientists in Britain and in the US (particularly Berkeley's Ernest Lawrence), Vannevar Bush at the National Defense Research Committee (NDRC) decided to review the prospects of nuclear energy further and engaged Arthur Compton and the National Academy of Sciences. Their report was issued 17 May 1941 but did not address the design or manufacture of a bomb in any detail.
On 15 July 1941 the MAUD Committee approved its two final reports and disbanded. One report was on 'Use of Uranium for a Bomb' and the other was on 'Use of Uranium as a Source of Power'. The first report concluded that a bomb was feasible, describing it in technical detail, providing specific proposals for developing a bomb and including cost estimates. It said that a bomb would contain about 12 kg of active material which would be equivalent to 1,800 tons of TNT and would release large quantities of radioactive substances which would make places near the explosion site dangerous to humans for a long period. It estimated that a plant to produce 1 kg of U-235 per day would cost £5 million and would require a large skilled labour force that was also needed for other parts of the war effort. It suggested that the Germans could also be working on the bomb, and so it recommended that the work should be continued with high priority in cooperation with the Americans, even though they seemed to be concentrating on the future use of uranium for power and naval propulsion.
The second MAUD Report concluded that the controlled fission of uranium could be used to provide energy in the form of heat for use in machines, as well as providing large quantities of radioisotopes which could be used as substitutes for radium. It referred to the use of heavy water and possibly graphite as moderators for the fast neutrons. It concluded that the 'uranium boiler' (i.e., a nuclear reactor) had considerable promise for future peaceful uses but that it was not worth considering during the present war. The Committee recommended that Hans von Halban and Lew Kowarski should move to the USA where there were plans to make heavy water on a large scale. The possibility that plutonium might be more suitable than U-235 was mentioned, and it suggested that this work should be continued in Britain.
Britain was at war and felt an atomic bomb was urgent; the USA was not at war. It was Marcus Oliphant who pushed the American programme into action. Oliphant flew to the United States in late August 1941 in an unheated bomber, ostensibly to discuss the radar programme, but was actually tasked to find out why the United States was ignoring the Maud Committee's findings. Oliphant reported: "The minutes and reports had been sent to Lyman Briggs, who was the Director of the Uranium Committee, and we were puzzled to receive virtually no comment. I called on Briggs in Washington, only to find out that this inarticulate and unimpressive man had put the reports in his safe and had not shown them to members of his committee. I was amazed and distressed."
Oliphant then met with the Uranium Committee. Samuel K. Allison was a new committee member, a talented experimentalist and a protégé of Arthur Compton at the University of Chicago. Oliphant "came to a meeting," Allison recalls, "and said 'bomb' in no uncertain terms. He told us we must concentrate every effort on the bomb and said we had no right to work on power plants or anything but the bomb. The bomb would cost 25 million dollars, he said, and Britain did not have the money or the manpower, so it was up to us." Allison was surprised that Briggs had kept the committee in the dark.
Oliphant then visited his friend Ernest Lawrence, James Conant and Enrico Fermi to explain the urgency. Lawrence then also contacted James Conant and Arthur Compton. In October 1941, Vannevar Bush presented the final Report draft to the President, who ordered Bush to obtain the blessing for a Bomb Project from the National Academy of Sciences; in December, Bush created the larger and more powerful Office of Scientific Research and Development (OSRD), which was empowered to engage in large engineering projects in addition to research, and became its director, leading to the creation of the Manhattan Project. Meanwhile in Britain a separate nuclear bomb programme continued under the code name Tube Alloys.
In 1943 the NKVD obtained a copy of the final report by the MAUD Committee. This led Stalin to order the start of a Soviet programme, but with very limited resources. Igor Kurchatov was appointed director of the nascent programme later that year.
- Brown, Andrew (1997). The Neutron and the Bomb: A Biography of Sir James Chadwick. Oxford University Press.
- Bundy, McGeorge (1988). Danger and Survival: Choices About the Bomb in the First Fifty Years. New York: Random House.
- Rhodes, Richard (1986). The Making of the Atomic Bomb. Simon & Schuster. ISBN 0-671-44133-7.
- World Nuclear Association - Outline History of Nuclear Energy
- Gowing, Margaret (1964). Britain and Atomic Energy, 1939-1945. quoted in Pierre, Andrew J Nuclear Politics : The British Experience With An Independent Strategic Force, 1939-1970 (1972), p16.
- Rhodes, Richard. Making of the Atomic Bomb. Simon and Schuster, New York, NY. 1996. pp. 340-341.