>>536017984
You've seen it before. This thing, an early component of the nuke.
Experimenting with it was volatile as you had to maintain a very small space of about a fraction of an inch and a slight deviation of that space would produce a instantaneous flash of light that would irradiate the researcher with a fatal dose of radiation. It killed two researchers in its time. First one died in 25 days. Second was 9 days.
>On the day of the accident, Slotin's screwdriver slipped outward a fraction of an inch while he was lowering the top reflector, allowing the reflector to fall into place around the core. Instantly, there was a flash of light; the core had become supercritical, releasing an intense burst of neutron radiation. Slotin quickly twisted his wrist, flipping the top shell to the floor. There was an estimated half-second between when the sphere closed to when Slotin removed the top reflector. Slotin received a lethal dose of 1,000 rad (10 Gy) neutron and 114 rad (1.14 Gy) gamma radiation in less than a second, while the position of Slotin's body over the apparatus shielded the others from much of the neutron radiation. Slotin died nine days later from acute radiation poisoning.