and suggested the Los Alamos Ranch School on the mesa. Dudley had rejected the school as not meeting Groves’ criteria, but as soon as Groves saw it he said in effect "This is the place". Oppenheimer became the laboratory's first director. During the Manhattan Project, Los Alamos hosted thousands of employees, including many Nobel Prize-winning scientists. The location was a total secret. Its only mailing address was a post office box, number 1663, in Santa Fe, New Mexico. Eventually two other post office boxes were used, 180 and 1539, also in Santa Fe. Though its contract with the University of California was initially intended to be temporary, the relationship was maintained long after the war. Until the atomic bombings of Hiroshima and Nagasaki, Japan, University of California president Robert Sproul did not know what the purpose of the laboratory was and thought it might be producing a "death ray". The only member of the UC administration who knew its true purpose—indeed, the only one who knew its exact physical location—was the Secretary-Treasurer Robert Underhill, who was in charge of wartime contracts and liabilities. The work of the laboratory culminated in several atomic devices, one of which was used in the first nuclear test near Alamogordo, New Mexico, codenamed "Trinity", on July 16, 1945. The other two were weapons, "Little Boy" and "Fat Man", which were used in the attacks on Hiroshima and Nagasaki. The Laboratory received the Army-Navy ‘E’ Award for Excellence in production on October 16, 1945. Post-war After the war, Oppenheimer retired from the directorship, and it was taken over by Norris Bradbury, whose initial mission was to make the previously hand-assembled atomic bombs "G.I. proof" so that they could be mass-produced and used without the assistance of highly trained scientists. Many of the original Los Alamos "luminaries" chose to leave the laboratory, and some even became outspoken opponents to the further development of nuclear weapons. The name officially changed to the Los Alamos Scientific Laboratory (LASL) on January 1, 1947. By this time, Argonne had already been made the first National Laboratory the previous year. Los Alamos would not become a National Laboratory in name until 1981. In the years since the 1940s, Los Alamos was responsible for the development of the hydrogen bomb, and many other variants of nuclear weapons. In 1952, Lawrence Livermore National Laboratory was founded to act as Los Alamos' "competitor", with the