1942 to 1943: Early Manhattan Project

1942 to 1943: Early Manhattan Project

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Chicago Pile Argonne

1942 Nov 16

Enrico Fermi's group begins constructing Chicago Pile-1 at Stagg Field using round-the-clock shifts. Also, Groves and Oppenheimer visit the Los Alamos, NM mesa in New Mexico and select it for "Site Y."

1942 Nov 3

Glenn Seaborg reports that due to plutonium's high alpha activity, slight amounts of light element impurities can cause a serious problem with neutron emission from alpha -> n reactions. This issue caused major concern with many project leaders, including Leslie Groves and James B. Conant, not only due to its own significance, but because it raised apprehension about the impact of other unexplored phenomena. (This issue later became moot due to the problems with Pu-240 contamination). Later in the month the Lewis Committee is formed to review progress and make recommendations.

1942 Oct 5

Gen. Leslie Groves visits the Chicago Met Lab and meets the key scientists, including J. Robert Oppenheimer. He orders key engineering decisions for plutonium production, under debate for months, be made in 5 days.

1942 Oct

James B. Conant recommends to Vannevar Bush that information exchange with Britain, already largely one-way (UK --> US), be sharply restricted. Bush passes this recommendation to President Roosevelt. As a result the US loses access to British work in gaseous diffusion, which seriously delays successful plant completion.