It's also memeable due to Louis Slotins blasé approach to safety, as the demon core was kept from going critical merely by shoving a screwdriver between the two half-sphere neutron-reflectors that it was kept inside.
If, or rather when (because it occurred twice), allowed to completely enclose it, they would cause it to go critical, emitting lethal amounts of radiation, instantly.
Louis and one other researcher died due to incidents involving accidental supercriticality. Many more were severely irradiated.