Timeline of The Manhattan Project - 1940

1940

• March 2: John R. Dunning's team at Columbia University verify Niels Bohr's hypothesis that Uranium 235 is responsible for fission by slow neutrons.
• March: Otto Frisch and Rudolph Peierls author the Frisch-Peierls memorandum, calculating that an atomic bomb might need as little as 1 pound (0.45 kg) of enriched uranium to work. This is given to Mark Oliphant, who in turn hands it over to Sir Henry Tizard.
• April 10: MAUD Committee established by Henry Tizard to investigate feasibility of an atomic bomb.
• May 21: George Kistiakowsky suggests using gaseous diffusion as a means of isotope separation.
• June 12: Roosevelt creates the National Defense Research Committee (NDRC) under Vannevar Bush, which absorbs the Uranium Committee.
• September 6: Bush tells Briggs that NDRC will provide $40,000 for the Uranium project.