DARK HISTORY: THE DEMON CORE

Ninetoes digs out the Gieger Counter to reaccount the beginning of the USA’s nuclear program, and the experiments of the infamous DEMON CORE

Hey there, history lovers! It is your old pal, Ninetoes, coming to you from Ninetoes HQ. Today, I am looking at The Demon Core Experiments. I have coffee in my system and my thinking cap on, so let’s get to it!

The Demon Core was a sphere of a plutonium-gallium alloy that was made in 1945 by the Manhattan Project. The core itself was around the size of a softball, 3.5 inches in diameter, and it weighed roughly 14 pounds. It was prepared to ship to the Pacific theater to be used as the third nuclear bomb dropped on Japan. When Japan surrendered, the core was then kept for testing and a possible later use if the need should arise. Two experiments proved fatal with the core.

The experiments were designed to see how much neutron reflection was required to get to supercriticality. The reflectors were arranged to guarantee the core reached the critical point. On August 21, 1945, the core produced a burst of neutron radiation that resulted in the death of Harry Daghilan’s death. He was working alone (there was a guard named Private Robert J. Hemmerly who was sitting at his desk 12 feet away), performing neutron reflector experiments on the core. The core was positioned within a stack of tungsten carbide bricks. The addition of bricks brought the core closer to criticality. When he went to stack another brick, it slipped and hit the core, causing it to go into supercriticality. He quickly moved the brick but received a lethal dose of (200 rads) radiation. He died 25 days later from acute radiation poisoning. The guard received 8 rads and died 33 years later of acute myelogenous leukemia.

The second incident occurred on May 21, 1946. Physicist Louis Slotin was showing a technique to his replacement, Alvin C. Graves. It involved placing two half-spherical shells of beryllium (a neutron reflector) around the core. The experiments needed to maintain slight separation between the halves using shims. If the halves closed completely, critical mass would be achieved immediately. Slotin did not use shims. He used screwdrivers. On the day of the accident, his screwdriver slipped a fraction of an inch, allowing the reflector to fall into place around the core. The core instantly became supercritical, and there was a flash of light and a burst of neutron radiation. Slotin quickly twisted his wrists to flip the top half of the sphere to the floor. There was a half second in which the shell was closed. That was enough time to give Slotin a dose of 1,000 rads of neutron radiation and 114 rads of gamma radiation.

The position of Slotin’s body pretty much shielded everyone else in the room from a lethal dose of radiation, but he knew that the damage to himself was done. He quickly sketched to show the placement of everyone in the room to help medical teams calculate specific dosages of radiation received by the survivors.

After these incidents, hands-on criticality experiments were stopped and were done by remote control machines and video cameras, with the personnel at a quarter-mile distance. This process was designed by Raemer Edgar Schreiber, a physicist and survivor of the Slotin experiment.

The Demon Core was to be shipped to the Marshal Islands for test code-named “Charlie”, but was never used after the incident involving the experiment code-named “Baker”. The core was melted down, and its material was recycled to be used in other cores.

Until the next time, I bid you successful research!

Darren “Ninetoes” Perdue is a book and media reviewer. When he is not reading, he is watching true crime shows, cooking for his family, or working on a plan for universal domination. If you see him on his porch, say hi. He does not bite…much.

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