May 15, 1942
President Franklin D. Roosevelt signs into law legislation creating the Women's Army Auxiliary Corps (converted into the Women's Army Corps in 1943).
President Franklin D. Roosevelt signs into law legislation creating the Women's Army Auxiliary Corps (converted into the Women's Army Corps in 1943).
Chemical separation of reactor-produced plutonium begins, using fuel from the X-10 Graphite Reactor pile.
Emilio Segre measures the spontaneous fission rate of U-235 at Los Alamos, NM, and finds it lower than expected. This allows a substantial reduction in performance of the planned gun assembly method for uranium.
After attempts to bring the first Alpha racetrack into operation fail, the Y-12 Plant is shut down for equipment rebuilding.
The first B-29 modifications begin at Wright Field, Ohio to adapt it for carrying atomic bombs.
The X-10 Graphite Reactor pile goes critical at Oak Ridge, TN. This air-cooled experimental pile begins producing the first substantial (gram) amounts of plutonium to assist research into its properties. The world supply of plutonium at this time is 2.5 mg, produced by cyclotrons. Also, a Manhattan Project Governing Board meeting approves an ambitious implosion research program, intended to develop it to the point of usability in six months.
The world's first sample of plutonium in metal form is produced by reducing PuF4 with Ba at the Chicago Met Lab.
The Navy approves Philip Abelson's plan to build a liquid thermal diffusion pilot plant for enriching uranium, the S-50 Plant.
The top experts in England on fission weapons, many former members of the MAUD committee, depart England for the US to assist the atomic bomb project. Included are Niels Bohr, Otto Frisch, Rudolf Peierls, James Chadwick, William Penney, George Placzek, Philip B. Moon, James Tuck, Egon Bretscher, and Klaus Fuchs.
First concrete is poured for the K-25 Plant building at Oak Ridge, TN.