Timeline of The Manhattan Project - 1946

1946

• February: News of the Canadian spy ring exposed by defector Igor Gouzenko is made public, creating a mild "atomic spy" hysteria, pushing American Congressional discussions about postwar atomic regulation in a more conservative direction.
• May 21: Louis Slotin, a physicist, received a fatal dose of radiation (2100 rems) when the screwdriver he was using to keep two beryllium hemispheres apart slipped; they were placed around the same plutonium core that had irradiated Daghilan. The upper hemisphere fell, causing a "prompt critical" reaction with a burst of hard radiation. Slotin lifted the upper hemisphere with his left hand and dropped it on the floor, so preventing a more serious accident. He was rushed to hospital, and died nine days later on May 30. Slotin had spent many hours with the dying Daghlian in 1945.
• July 1: Able test at Bikini Atoll as part of Operation Crossroads.
• July 25: Underwater Baker test at Bikini.
• August 1: Truman signs the Atomic Energy Act of 1946 into law, ending almost a year of uncertainty about the control of atomic research in the postwar United States.