Nuclear chain reaction the last one called ""Perfectionnement aux charges explosives"" was the first patent for the atomic bomb and is filed as patent n°445686 by the Caisse nationale de Recherche Scientifique. In parallel, Szilárd and Enrico Fermi in New York made the same analysis. This discovery prompted the letter from Szilárd and signed by Albert Einstein to President Franklin D. Roosevelt, warning of the possibility that Nazi Germany might be attempting to build an atomic bomb. On December 2, 1942, a team led by Enrico Fermi produced the first artificial self-sustaining nuclear chain reaction with the Chicago Pile-1 (CP-1) experimental reactor in
Enrico Fermi He was the third child of Alberto Fermi, a division head ("") in the Ministry of Railways, and Ida de Gattis, an elementary school teacher. His sister, Maria, was two years older than him, and his brother Giulio was a year older. After the two boys were sent to a rural community to be wet nursed, Enrico rejoined his family in Rome when he was two and a half. Although he was baptised a Roman Catholic in accordance with his grandparents' wishes, his family was not particularly religious; Enrico was an agnostic throughout his adult life. As a young boy