Demon Core

Demon Core ( dt demons core ) is the nickname of a 6.2 kg heavy plutonium core, which reached a supercritical mass in two accidents in the Los Alamos National Laboratory. In both accidents, the triggering scientist died of the consequences.

First incident on August 21, 1945

Physicist Harry K. Daghlian Jr. worked alone in an experiment on the effect of tungsten carbide as a neutron reflector. He stacked bars of tungsten carbide around the plutonium core. When he wanted to create an additional bars on the stack, showed him a scintillation counter that the neutron radiation had increased. He realized that the next bars, the mass would be critical, and he withdrew his hand. In this case, the ingot has been dropped onto the core, and resulted in the release of ionizing radiation. He removed the bars immediately but still a lethal dose of radiation has been suspended. Daghlian died 25 days later, on 15 September 1945.

Second incident on May 21, 1946

The Canadian physicist Louis Slotin and seven of his colleagues were working on an experiment in which the initial phase of a chain reaction should be initiated. To this end, they arranged two beryllium hemispheres as neutron reflectors around a plutonium core. Was decisive was that the beryllium hemispheres were not allowed to put in a complete sphere around the plutonium core. Slotin had already carried out similar experiments and the danger was aware. The experimental setup was also tickling the dragon 's tail (Eng. " the dragon 's tail tickle " ) called. Normally, the safety distance between the two Berylliumhälften was ensured by a mechanism on rails, which pushed slowly toward the beryllium hemispheres of plutonium and thus increased the reactivity. A spacer prevented contact between the two hemispheres. Day of the accident, the test was changed: Slotin kept the beryllium hemisphere in the hand and led her slowly towards the plutonium. Instead of the spacer it uses a screwdriver in order to prevent the contact of the two hemispheres beryllium. Here, the screw slipped out of the core is completely enclosed by plutonium beryllium, and it has been triggered a chain reaction, leading to the release of a high radiation dose. Slotin was able to stop the reaction, he pulled away by a hemisphere, and prevented so that the other attendees were given lethal doses. He died nine days later from acute radiation sickness. His assistant, who was standing right next to him, suffered serious injuries and permanent damage. In some sources it is assumed that three other scientists died years later at the after-effects of the accident.

Subsequent use of the plutonium core

The Demon Core was installed in a Mk.3 - atomic bomb and fired on July 1, 1946 at Able - nuclear test in Bikini Atoll during Operation Crossroads.

Pop culture

The accidents were summarized in the movie " Fat Man and Little Boy" from 1989.