Editing Nuclear weapon design (section)

===Los Alamos===
{{Main|Los Alamos National Laboratory}}
At Los Alamos, it was found in April 1944 by [[Emilio Segrè]] that the proposed [[Thin Man nuclear bomb|Thin Man]] Gun assembly type bomb would not work for plutonium because of predetonation problems caused by [[Pu-240]] impurities. So Fat Man, the implosion-type bomb, was given high priority as the only option for plutonium. The Berkeley discussions had generated theoretical estimates of critical mass, but nothing precise. The main wartime job at Los Alamos was the experimental determination of critical mass, which had to wait until sufficient amounts of fissile material arrived from the production plants: uranium from [[Oak Ridge, Tennessee]], and plutonium from the [[Hanford Site]] in Washington.{{Citation needed|date=June 2021}}

In 1945, using the results of critical mass experiments, Los Alamos technicians fabricated and assembled components for four bombs: the ''[[Trinity test|Trinity]]'' [[the gadget|Gadget]], Little Boy, Fat Man, and an unused spare Fat Man. After the war, those who could, including Oppenheimer, returned to university teaching positions. Those who remained worked on levitated and hollow pits and conducted weapon effects tests such as [[Operation Crossroads|Crossroads]] Able and Baker at [[Bikini Atoll]] in 1946.{{Citation needed|date=June 2021}}

All of the essential ideas for incorporating fusion into nuclear weapons originated at Los Alamos between 1946 and 1952. After the [[Teller-Ulam design|Teller-Ulam]] radiation implosion breakthrough of 1951, the technical implications and possibilities were fully explored, but ideas not directly relevant to making the largest possible bombs for long-range Air Force bombers were shelved.{{Citation needed|date=June 2021}}

Because of Oppenheimer's initial position in the H-bomb debate, in opposition to large thermonuclear weapons, and the assumption that he still had influence over Los Alamos despite his departure, political allies of [[Edward Teller]] decided he needed his own laboratory in order to pursue H-bombs. By the time it was opened in 1952, in [[Lawrence Livermore National Laboratory|Livermore]], California, Los Alamos had finished the job Livermore was designed to do.{{Citation needed|date=June 2021}}