{"id":623774,"date":"2026-01-18T22:10:47","date_gmt":"2026-01-18T21:10:47","guid":{"rendered":"https:\/\/cronologia-universale.it\/1943-1944\/"},"modified":"2026-01-18T22:10:47","modified_gmt":"2026-01-18T21:10:47","slug":"december-1940","status":"publish","type":"post","link":"https:\/\/cronologia-universale.it\/en\/december-1940\/","title":{"rendered":"December 1940"},"content":{"rendered":"<p>Emilio Segre&#8217; and Enrico Fermi discuss the possible use of a controlled reaction with Uranium 238 (element 92) to first obtain an isotope of Neptunium 239 (element 93) and then, by radioactive decay (2.3 days), an isotope of Plutonium 239 (element 94). 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