The first contact with the government was made by G.
The S-1 Committee held its meeting on 18 December "pervaded by an atmosphere of enthusiasm and urgency"  in the wake of the attack on Pearl Harbor and the subsequent United States declaration of war upon Japan and then on Germany.
Lawrence and his team at the University of California, Berkeleyinvestigated electromagnetic separationwhile Eger Murphree and Jesse Wakefield Beams 's team looked into gaseous diffusion at Columbia Universityand Philip Abelson directed research into thermal diffusion at the Carnegie Institution of Washington and later the Naval Research Laboratory.
Styerthe chief of staff of Major General Brehon B. Somervell 's Services of Supplywho had been designated the Army's representative on nuclear matters. Robert Oppenheimer of the University of California, Berkeley, to take over research into fast neutron calculations —the key to calculations of critical mass and weapon detonation—from Gregory Breitwho had quit on 18 May because of concerns over lax operational security.
Manleya physicist at the Metallurgical Laboratory, was assigned to assist Oppenheimer by contacting and coordinating experimental physics groups scattered across the country.
They tentatively confirmed that a fission bomb was theoretically possible. The properties of pure uranium were relatively unknown, as were those of plutonium, an element that had only been discovered in February by Glenn Seaborg and A history of the manhattan project and the atomic bombing team.
The scientists at the Berkeley conference envisioned creating plutonium in nuclear reactors where uranium atoms absorbed neutrons that had been emitted from fissioning uranium atoms. At this point no reactor had been built, and only tiny quantities of plutonium were available from cyclotrons.
The simplest was shooting a "cylindrical plug" into a sphere of "active material" with a "tamper"—dense material that would focus neutrons inward and keep the reacting mass together to increase its efficiency.
Tolmanand the possibility of autocatalytic methodswhich would increase the efficiency of the bomb as it exploded. Edward Teller pushed for discussion of a more powerful bomb: The fusion idea was put aside to concentrate on producing fission bombs. It somehow got into a document that went to Washington" and was "never laid to rest".
Marshall to head the Army's part of the project in June Marshall created a liaison office in Washington, D. He had permission to draw on his former command, the Syracuse District, for staff, and he started with Lieutenant Colonel Kenneth Nicholswho became his deputy.
Robbinsand his deputy, Colonel Leslie Groves. Reybold, Somervell, and Styer decided to call the project "Development of Substitute Materials", but Groves felt that this would draw attention. Since engineer districts normally carried the name of the city where they were located, Marshall and Groves agreed to name the Army's component of the project the Manhattan District.
This became official on 13 August, when Reybold issued the order creating the new district. Unlike other districts, it had no geographic boundaries, and Marshall had the authority of a division engineer. Development of Substitute Materials remained as the official codename of the project as a whole, but was supplanted over time by "Manhattan".
The War Production Board recommended sites around Knoxville, Tennesseean isolated area where the Tennessee Valley Authority could supply ample electric power and the rivers could provide cooling water for the reactors.
After examining several sites, the survey team selected one near Elza, Tennessee. Conant advised that it be acquired at once and Styer agreed but Marshall temporized, awaiting the results of Conant's reactor experiments before taking action.
The first step was to obtain a high priority rating for the project. Claythe deputy chief of staff at Services and Supply for requirements and resources, felt that the highest rating he could assign was AA-3, although he was willing to provide a AAA rating on request for critical materials if the need arose.
The white overshoes prevented fallout from sticking to the soles of their shoes. He wanted the project placed under a senior policy committee, with a prestigious officer, preferably Styer, as overall director.
Nelson initially balked but quickly caved in when Groves threatened to go to the President. It soon transpired that for the routine requirements of the project the AAA rating was too high but the AA-3 rating was too low.
After a long campaign, Groves finally received AA-1 authority on 1 July Most everything proposed in the Roosevelt administration would have top priority.
That would last for about a week or two and then something else would get top priority". The obvious choice was one of the three laboratory heads, Urey, Lawrence, or Compton, but they could not be spared.
Compton recommended Oppenheimer, who was already intimately familiar with the bomb design concepts. However, Oppenheimer had little administrative experience, and, unlike Urey, Lawrence, and Compton, had not won a Nobel Prizewhich many scientists felt that the head of such an important laboratory should have.
There were also concerns about Oppenheimer's security status, as many of his associates were Communistsincluding his brother, Frank Oppenheimer ; his wife, Kitty; and his girlfriend, Jean Tatlock. A long conversation on a train in October convinced Groves and Nichols that Oppenheimer thoroughly understood the issues involved in setting up a laboratory in a remote area and should be appointed as its director.
Groves personally waived the security requirements and issued Oppenheimer a clearance on 20 July British contribution to the Manhattan Project The British and Americans exchanged nuclear information but did not initially combine their efforts. Britain rebuffed attempts by Bush and Conant in to strengthen cooperation with its own project, codenamed Tube Alloysbecause it was reluctant to share its technological lead and help the United States develop its own atomic bomb.After the bombings at Hiroshima and Nagasaki, a number of Manhattan Project physicists founded the Bulletin of the Atomic Scientists, which began as an emergency action undertaken by scientists who saw urgent need for an immediate educational program about atomic weapons.
The atomic bomb project thus became known as the Manhattan Engineer District (MED), or Manhattan Project for short. Its first major funding came in December, when President Roosevelt ordered an initial allotment of $ million. In December , the government launched the Manhattan Project, the scientific and military undertaking to develop the bomb.
A Letter to the President In August , Einstein wrote to U.S. President Franklin Roosevelt to warn him that the Nazis were working on a new and powerful weapon: an atomic bomb.
During World War II, American physicists and engineers began a race against Nazi Germany to create the first atomic bomb. This secret endeavor lasted from until under the codename “the Manhattan Project.” In the end, it would be a success in that it forced Japan to surrender and.
Also used was the report on "The Atomic Bombings of Hiroshima and Nagasaki" in the official Manhattan District History, produced by the War Department in at the direction of Leslie Groves, especially pages ; the "Atomic Bombings" document is available in the University Publications of America microfilm collection, Manhattan Project: Official History and Documents (Washington: ), reel .
Jul 26, · Watch video · Legacy of the Manhattan Project ; Sources ; The Manhattan Project was the code name for the American-led effort to develop a functional atomic weapon during World War II.