On 2 December of 1942 (I quote the site of the National Institute of Nuclear Physics), “Under the bleachers of the stadium of the University of Chicago, Fermi put into operation the first atomic pile in the presence of about forty colleagues and technicians. Twenty-eight minutes later the reaction was arrested: Wigner uncorked a bottle of Chianti that he had been saving for weeks for the occasion and Compton phoned the rector of Harvard University giving him the message of Fermi’s success in code: Jim, you’ll be glad to know that the Italian navigator recently arrived in the new world“.
Americans, they have an epic sense of history, they tell it this way: “The Atomic Era began inside a huge tent on a squash court under the stands of the University of Chicago’s Stagg Field.” To get some context you need to go on the website of the Enrico Fermi Center in Rome, where it is explained that the scientist had now been living for some years in the United States, where he had fled with his family following the racial laws; and on 2 December 1942 it ended the construction of the “first artificial nuclear fission reactor in the world“. It was called Chicago Pile-1 and was made up of a pile of uranium and graphite blocks: “The pile had a core made up of uranium pellets, which produced neutrons; the pellets were separated by graphite blocks to moderate the speed of the neutrons ”.
Construction should have been done at Argonne National Laboratory, but due to a strike it was not possible, then Fermi chose to do so at an abandoned stadium: “At 3.25 pm on December 2, the Cp-1 reactor had reached the critical mass to self-feed the chain reaction. Fermi personally checked the neutron activity e after 28 minutes he decided to turn off the machine. A little less than thirty minutes had been enough to demonstrate that a self-propelled chain reaction could be activated ”.
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