It went critical in 1946, and was used for scientific experiments until 1953, when it was dismantled. Hall's research interests included nuclear reactor development, X-ray crystallography and neutron physics, and cosmic rays. In 1951 she informed Robert Oppenheimer of the results of the Operation Greenhouse George nuclear test, in which the yield of an atomic bomb was "boosted" by the addition of a small capsule containing less than of deuterium and tritium, which nonetheless increased the yield by . Hall became associate director of the Los Alamos National Laboratory in 1958. That year she was an American delegate at the Atoms for Peace Conference in Geneva. She was secretary of the General Advisory Committee (GAC) of the Atomic Energy Commission (AEC) from 1956 until 1959, and was a member of the GAC from 1966 to 1972. When President Lyndon Johnson appointed her in 1966, she became the first woman to serve on the GAC. She was also a member of the AEC Advisory committee on Nuclear Materials and Safeguards from 1967 to 1972. She retired from the Los Alamos National Laboratory in 1970. In October of that year, the chairman of the AEC, Glenn Seaborg, presented her with the Atomic Energy Commission Citation and gold medal. She died in November 1981.