Omega
Post by beth on Jul 18, 2010 16:40:56 GMT -5
The two types of fission weapon designs pursued during the Manhattan Project.
April 5: At Los Alamos, Emilio Segrè receives the first sample of reactor-bred plutonium from Oak Ridge, and within ten days discovers that the spontaneous fission rate is too high for use in a gun-type fission weapon.
May: Fermi at Los Alamos tests the world's third reactor, LOPO, the first aqueous homogeneous reactor, and the first fueled by enriched uranium.
July 4: Oppenheimer reveals Segrè's final measurements to the Los Alamos staff, and the development of the gun-type plutonium weapon "Thin Man" is abandoned. Designing a workable "implosion" design becomes top priority of the laboratory.
July 20: The Los Alamos organizational structure is completely changed to reflect the new priority of "implosion".
July 25: First preliminary test of the RaLa Experiment series performed
September 2: chemists Peter N. Bragg, Jr. [2] and Douglas P. Meigs [3] are killed, and Arnold Kramish almost killed, while attempting to unclog a uranium enrichment device which is part of the pilot thermal diffusion plant at the Philadelphia Navy Yard. Two soldiers, George LeFevre and John Tompkins, also receive extensive injuries. An explosion of liquid uranium hexafluoride burst nearby steam pipes, and steam combined with the uranium hexafluoride to spray them with highly corrosive hydrofluoric acid. See also [4] [5] and [6]
September 22: First RaLa test with a radioactive source performed
December 9: 509th Composite Group of USAAF constituted to deliver the bomb
December 14: Definite evidence of achievable compression obtained in a RaLa test
Mid-December: Successful test of explosive lens for Fat Man.