Nuclear fission the Manhattan Project during World War II (September 1, 1939 – September 2, 1945) carried out most of the early scientific work on fission chain reactions, culminating in the three events involving fission bombs that occurred during the war. The first fission bomb, codenamed "The Gadget", was detonated during the Trinity Test in the desert of New Mexico on July 16, 1945. Two other fission bombs, codenamed "Little Boy" and "Fat Man", were used in combat against the Japanese cities of Hiroshima and Nagasaki in on August 6 and 9, 1945 respectively. Even the first fission bombs were thousands of
Raemer Schreiber Raemer Schreiber Raemer Edgar Schreiber (November 11, 1910 – December 24, 1998) was an American physicist from McMinnville, Oregon who served Los Alamos National Laboratory during World War II, participating in the development of the atomic bomb. He saw the first one detonated in the Trinity nuclear test in July 1945, and prepared the Fat Man bomb that was used in the bombing of Nagasaki. After the war, he served at Los Alamos as a group leader, and was involved in the design of the hydrogen bomb. In 1955, he became the head of its Nuclear Rocket Propulsion (N) Division,