A sphere of plutonium, a screwdriver, and one small mistake.

☢️ One tiny mistake. One burst of radiation. One of the most infamous accidents in nuclear science. On May 21, 1946, physicist Louis Slotin was conducting a criticality experiment at Los Alamos National Laboratory. The experiment involved a plutonium core surrounded by beryllium reflector shells. Slotin was carefully bringing the shells closer together to study how close the assembly could get to criticality—the point where a nuclear chain reaction becomes self-sustaining. Then the screwdriver he was using to keep the shells separated slipped. The shells moved together, briefly driving the plutonium assembly into a critical state. Witnesses saw a blue flash caused by ionization of the surrounding air, accompanied by an intense burst of neutron and gamma radiation. Slotin immediately separated the shells, stopping the reaction, but he had already received a lethal radiation dose. He developed severe radiation sickness and died nine days later on May 30, 1946, at age 35. But the most chilling part? The same plutonium core had already been involved in another fatal criticality accident. On August 21, 1945, physicist Harry Daghlian accidentally caused the same core to go critical while working with neutron-reflecting bricks. He died 25 days later, on September 15, from radiation poisoning. After Slotin's death, the core became known as the “Demon Core.” The two accidents also transformed laboratory safety. Los Alamos moved criticality experiments toward remote operation, reducing the need for scientists to work directly beside dangerous assemblies. Two scientists. One plutonium core. Two fatal accidents. A terrifying reminder that in nuclear physics, the difference between safe and critical can be incredibly small. 👇 Would you have been willing to perform an experiment like this in 1946? 📚 Shared for educational and historical purposes. 📩 DM for credit or removal. Follow @astrashristi for daily physics, nuclear science, engineering, technology, and fascinating history. ☢️🚀 #DemonCore #LouisSlotin #HarryDaghlian #NuclearPhysics #Radiation #Criticality #ManhattanProject #NuclearScience #Physics #ScienceHistory #LosAlamos #AtomicHistory #Engineering #PhysicsFacts #ScienceFacts #STEM #NuclearTechnology #ScienceReels #Astrashristi