A softball-sized lump of plutonium sat on a Los Alamos workbench in 1945, close enough to fission that a slipped screwdriver could kill a man. It did — twice. This is the story of the core that 'tickled the dragon's tail' and the physicists who paid for it with agonizing, radioactive deaths.
The full narrative in one video: how a 6.2 kg plutonium sphere meant for a third atomic bomb became the deadliest object in the lab. Start here for the human arc before you dive into the physics.
The reference dossier on the object itself: 89mm across, 14 pounds, beryllium reflectors, and the two supercriticality events that gave it its nickname after the war ended and it was no longer needed for a bomb.
August 21, 1945. Harry Daghlian, alone at night, drops a tungsten-carbide brick onto the core and watches it flash blue. He would die 25 days later. The first warning nobody heeded.
'Tickling the tail of the dragon' — how criticality demonstrations became casual lab theater, and why it took two deaths to end hands-on experiments forever.
May 21, 1946. Slotin held two plutonium hemispheres apart with the blade of a screwdriver. It slipped. A blue glow, a wave of heat, and he knew instantly he was dead — but he yanked them apart and saved seven colleagues.
The nine days that followed: the vomiting, the reddening skin, the disintegration of a man who had just committed one of history's most public acts of self-sacrifice-by-physics.
The clinical afterlife of the accidents: what the radiation actually did to Daghlian's and Slotin's bodies, and how their deaths became foundational data for radiation medicine.