British contribution to the Manhattan Project

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James Chadwick (left), the head of the British Mission, confers with Major General Leslie R. Groves, Jr. (right), the director of the Manhattan Project

Britain contributed to the Manhattan Project by helping initiate the effort to build the first atomic bombs in the United States during World War II, and helped carry it through to completion in August 1945 by supplying crucial expertise. Following the discovery of nuclear fission in uranium, scientists Rudolf Peierls and Otto Frisch at the University of Birmingham calculated, in March 1940, that the critical mass of a metallic sphere of pure uranium-235 was as little as 1 to 10 kilograms (2.2 to 22.0 lb), and would explode with the power of thousands of tons of dynamite. The Frisch–Peierls memorandum prompted Britain to create an atomic bomb project, known as Tube Alloys. Mark Oliphant, an Australian physicist working in Britain, was instrumental in making the results of the British MAUD Report known in the United States in 1941 by a visit in person. Initially the British project was larger and more advanced, but after the United States entered the war, the American project soon outstripped and dwarfed its British counterpart. The British government then decided to shelve its own nuclear ambitions, and participate in the American project.

In August 1943, the Prime Minister of the United Kingdom, Winston Churchill, and the President of the United States, Franklin D. Roosevelt, signed the Quebec Agreement, which provided for cooperation between the two countries. The Quebec Agreement established the Combined Policy Committee and the Combined Development Trust to coordinate the efforts of the United States, the United Kingdom and Canada. The subsequent Hyde Park Agreement in September 1944 extended this cooperation to the postwar period. A British Mission led by Wallace Akers assisted in the development of gaseous diffusion technology in New York. Britain also produced the powdered nickel required by the gaseous diffusion process. Another mission, led by Oliphant who acted as deputy director at the Berkeley Radiation Laboratory, assisted with the electromagnetic separation process. As head of the British Mission to the Los Alamos Laboratory, James Chadwick led a multinational team of distinguished scientists that included Sir Geoffrey Taylor, James Tuck, Niels Bohr, Peierls, Frisch, and Klaus Fuchs, who was later revealed to be a Soviet atomic spy. Four members of the British Mission became group leaders at Los Alamos. William Penney observed the bombing of Nagasaki and participated in the Operation Crossroads nuclear tests in 1946.

Cooperation ended with the Atomic Energy Act of 1946, known as the McMahon Act, and Ernest Titterton, the last British government employee, left Los Alamos on 12 April 1947. Britain then proceeded with High Explosive Research, its own nuclear weapons programme, and became the third country to test an independently developed nuclear weapon in October 1952.

How did a project like Tube Alloys fail? How did Manhattan Island view from Columbia University not get caught?

Origins[edit]

Australian physicist Mark Oliphant was a key figure in the launching of both the British and United States nuclear weapons programmes

The 1938 discovery of nuclear fission in uranium by Otto Robert Frisch, Fritz Strassmann, Lise Meitner and Otto Hahn,^[1] raised the possibility that an extremely powerful atomic bomb could be created.^[2] Refugees from Nazi Germany and other fascist countries were particularly alarmed by the notion of a German nuclear weapon project.^[3] In the United States, three of them, Leo Szilard, Eugene Wigner and Albert Einstein, were moved to write the Einstein–Szilárd letter to the President of the United States, Franklin D. Roosevelt, warning of the danger. This led to the President creating the Advisory Committee on Uranium. In Britain, Nobel Prize in Physics laureates George Paget Thomson and William Lawrence Bragg were sufficiently concerned to take up the matter. Their concerns reached the Secretary of the Committee of Imperial Defence, Major General Hastings Ismay, who consulted with Sir Henry Tizard. Like many scientists, Tizard was sceptical of the likelihood of an atomic bomb being developed, reckoning the odds against success at 100,000 to 1.^[4]

Even at such long odds, the danger was sufficiently great to be taken seriously. Thomson, at Imperial College London, and Mark Oliphant, an Australian physicist at the University of Birmingham, were tasked with carrying out a series of experiments on uranium. By February 1940, Thomson’s team had failed to create a chain reaction in natural uranium, and he had decided that it was not worth pursuing.^[5] But at Birmingham, Oliphant’s team had reached a strikingly different conclusion. Oliphant had delegated the task to two German refugee scientists, Rudolf Peierls and Otto Frisch, who could not work on the University’s radar project because they were enemy aliens and therefore lacked the necessary security clearance.^[6] They calculated the critical mass of a metallic sphere of pure uranium-235, the only fissile isotope found in significant quantity in nature, and found that instead of tons, as everyone had assumed, as little as 1 to 10 kilograms (2.2 to 22.0 lb) would suffice, which would explode with the power of thousands of tons of dynamite.^[7][8][9]

Oliphant took the Frisch–Peierls memorandum to Tizard, and the MAUD Committee was established to investigate further.^[10] It directed an intensive research effort, and in July 1941, produced two comprehensive reports that reached the conclusion that an atomic bomb was not only technically feasible, but could be produced before the war ended, perhaps in as little as two years. The Committee unanimously recommended pursuing the development of an atomic bomb as a matter of urgency, although it recognised that the resources required might be beyond those available to Britain.^[11][12] A new directorate known as Tube Alloys was created to coordinate this effort. Sir John Anderson, the Lord President of the Council, became the minister responsible, and Wallace Akers from Imperial Chemical Industries (ICI) was appointed the director of Tube Alloys.^[13]

Early Anglo-American cooperation[edit]

In July 1940, Britain had offered to give the United States access to its scientific research,^[14] and the Tizard Mission‘s John Cockcroft briefed American scientists on British developments. He discovered that the American project was smaller than the British, and not as far advanced.^[11] As part of the scientific exchange, the Maud Committee’s findings were conveyed to the United States. Oliphant, one of the Maud Committee’s members, flew to the United States in late August 1941, and discovered that vital information had not reached key American physicists. He met the Uranium Committee, and visited Berkeley, California, where he spoke persuasively to Ernest O. Lawrence, who was sufficiently impressed to commence his own research into uranium at the Berkeley Radiation Laboratory. Lawrence in turn spoke to James B. Conant, Arthur H. Compton and George B. Pegram. Oliphant’s mission was a success; key American physicists became aware of the potential power of an atomic bomb.^[15][16] Armed with British data, Vannevar Bush, the director of the Office of Scientific Research and Development (OSRD), briefed Roosevelt and Vice President Henry A. Wallace in a meeting at the White House on 9 October 1941.^[17]

Sir John Anderson, minister responsible for Tube Alloys

The British and Americans exchanged nuclear information, but did not initially combine their efforts. British officials did not reply to an August 1941 offer by Bush and Conant to create a combined British and American project.^[18] In November 1941, Frederick L. Hovde, the head of the London liaison office of OSRD, raised the issue of cooperation and exchange of information with Anderson and Lord Cherwell, who demurred, ostensibly over concerns about American security. Ironically, it was the British project that had already been penetrated by atomic spies for the Soviet Union.^[19]