Thin Man (nuclear bomb) Thin Man (nuclear bomb) "Thin Man" was the code name for a proposed plutonium gun-type nuclear bomb using plutonium-239 which the United States was developing during the Manhattan Project. They aborted its development when they discovered that the spontaneous fission rate of their nuclear reactor-bred plutonium was too high for use in a gun-type design, due to the high concentration of the isotope plutonium-240. In 1942, prior to the Army taking over wartime atomic research, Robert Oppenheimer held conferences in Chicago in June and Berkeley, California, in July at which various engineers and physicists discussed nuclear bomb design issues. A
Riazuddin (physicist) preferred to use the scientific research rationale. The Theoretical Physics Group began its research and directly reported to Abdus Salam. In 1977 both MPG and TPG scientists completed the design and calculation of an atomic bomb. Along with Qadir, Riazuddin continued to develop the theoretical designs of the atomic weapon during 1978. In 1982 the PAEC finally developed the device under the leadership of Munir Ahmad Khan. The PAEC carried out the first cold-test of the TPG's theoretical design by May 1983 at Kirana Hills. The test teams were headed by Ishfaq Ahmad, a nuclear physicist, and Munir Ahmad Khan