# Oppenheimer Robert J. Oppenheimer (1904-1967), American physicist, director (1942-1945) of the laboratory at Los Alamos, New Mexico, that designed and built the first atomic bombs. Oppenheimer later became a main proponent of the civilian and international control of atomic energy. Oppenheimer strongly opposed, on both technical and moral grounds, the development of the hydrogen bomb. He was suspended from the chairmanship of the US Atomic Energy Commission in 1953 as an alleged security risk.