Tha Manhattan Project was the code name for the United States effort to develop the atomic bomb before the Germans did. This is was in large response to the first successful experiments in splitting a uranuim atom being carried out in the autumn of 1938 at the Kaiser Wilhelm Institute in Berlin. So the race was on.
The most complicated issue that faced the scientists working on the Manhattan Project was the production of ample amounts of "enriched" uranium to sustain a chain reaction. With the technology that was possessed back then, Uranium-235 was almost impossible to extract. Of the total Uranium ore mined, only about 1/500 of it ended up as Uranium metal. And of this Uranium metal, the Uranium-235 is so rare that it occurs at a ratio of 1 to 139. Seperating the one part Uranium-235 from the 139 parts Uranium-238 proved to be a challenge. You could not seperate the two isotopes using a cheimcal extraction, but only mechanical methods could effectively seperate the two. Scientist at Columbia University set out to solve this probelm.
A huge lab was built at Oak Ridge, Tennessee. H.V. Urey, and his associates at Columbia University designed a system that worked on the principle of gaseous diffusion. After this process was completed, Ernest O. Lawrence implemented a process involving magnetic separation of the two isotopes. Finally, a gas centrifuge was used to seperate the Uranium-235 from the Uranium-238. The Uranium-238 was forced to the bottom of the cylinder because it had more mass than the Uranium-235. In this procedure, the Uranium-235 was enriched from its normal 0.7% to weapons grade of more than 90%.
This Uranium was then transported a laboratory in Los Alamos New Mexico headed by J. Robert Oppenheimer. Oppenheimer was essentially the major force behind the Manhattan Project. Once the purified Uranium reached New Mexico, it was made into the components of a gun-type atomic weapon. The concept behind this was as follows: Two pieces of Uranium-235, individually not large enough to sustain a chain reaction, were brought together reapidly in a gun barrel to form a supercrital mass that exploded instantaneously. It was orginally nicknamed "Thin Man", after Roosevelt, but later renamed "Little Boy", after nobody. The scientists were so confident that the gun-type atomic bomb would work that no tests were conducted, and was immediatly dropped over Hiroshima, Japan, on Aug. 6, 1945.
Copyright @1998 Matt Fields