Learn the story of the demonic core that killed two scientists

The world has recently been alerted by threats from North Korean dictator Kim Jong-Un to drop an atomic bomb on the US. But about 73 years ago, it was the US that dropped two atomic bombs on Japan, leaving the world very afraid that the act had been the trigger of a nuclear war.

The technology became militarily viable, but it was not safe. In addition to the artifacts' own destructive power, some cases of accidents were recorded during research. The total number is not known for certain, as the subject required secrecy, but they were usually deadly to those close to them.

The end of the war

The bombing, luckily for all mankind, had the desired effect, and Japan surrendered. Still, there was a third plutonium core prepared for another attack. He was under the responsibility of scientists at the Los Alamos National Laboratory and would be known as the Demon Core.

Part of one of the experiments.

Part of one of the experiments.

During a nuclear explosion, the radioactive nucleus is activated to initiate a chain reaction, and thereafter the speed of the reaction increases uncontrollably. This second phase is called supercritical and known to scientists, but they wanted to know what were the core boundaries to enter this mode.

One way to test this limit is to replay the neutrons released by the nucleus in it to further destabilize it. One group, called the “Critical Assembly Group”, developed a series of experiments involving the nucleus with materials that reflected the released neutrons, following the evolution of the activity.

Needless to say, studying boundary atomic reactions is a very dangerous activity. So much so that 12 days after the launch of the second bomb, even before Japan signed the surrender terms, the first accident occurred during the tests.

Physicist Harry Daghlian was alone in the lab, building a tungsten carbide shield around the core. During the process, neutrons were being reflected until the physicist positioned a piece of the shield that left the nucleus very cloistered. This activated the supercritical phase, and he was exposed to a lethal dose of radiation, dying 25 days later.

Resumption of Searches

Louis Slotin

Louis Slotin with one of the first US bombs

The accident did not cause the project to be canceled, so much so that 9 months later new tests began. At the time, a mechanism was developed that pushed the nucleus almost to the limit by lowering a beryllium dome over it.

Louis Slotin, a Canadian physicist, had become accustomed to operating the new experiment model. With one hand he held the dome while the other held a screwdriver that regulated the opening. Despite the extremely rudimentary method, this limited neutron reflection and kept core stability controlled.

In the last experiment performed, his hand slipped, and the dome closed completely, causing the nucleus to enter the supercritical state again. Seven other scientists were present in the room, but only Louis died nine days later.

Louis Slotin

Louis Slotin and the study that led to his death

In both cases, when the nucleus passed its limit and began the process of radiation emission, a blue light took over the environment. This was the result of the shock of highly energized particles with the air molecules, which released their energy as beams of light.

After the incident, the search was halted and the nucleus likely detonated in a test blast that took place 5 weeks after the event.