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1939 to 1941: Investigating Nuclear Weapons

1939 to 1941: Investigating Nuclear Weapons

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July 15, 1941

The MAUD Committee approves its final report and disbands. The report describes atomic bombs in some technical detail, provides specific proposals for developing them, and includes cost estimates. Although the contents of The MAUD Report reach Vannevar Bush at The Office of Scientific Research and Development immediately, he decides to wait for the report to be transmitted officially before taking any further action on fission development. In short, the report concludes that an atomic bomb is indeed feasible.

May 18, 1941

Emilio Segre and Glenn Seaborg determine that the slow cross-section of plutonium-239 is 170% of that of uranium-235, proving it to be an even better prospect for a nuclear explosive.

May 1941

Tokutaro Hagiwara at the University of Kyoto delivers a speech in which he discusses the possibility of a fusion explosion being ignited by an atomic bomb, apparently the first such mention.

May 1941

After months of growing pressure from scientists in Britain and the U.S. (particularly University of California at Berkeley's Ernest O. Lawrence), Vannevar Bush at The National Defense Research Committee decides to review the prospects of nuclear energy further and engages Arthur H. Compton and the National Academy of Sciences for the task. The report is issued May 17 and treats military prospects favorably for power production, but does not address the design or manufacture of a bomb in any detail.