Science : Have you ever heard about the demon core?

Have you ever heard about the demon core?

Specially the accidental death of Louis Slotin?


On May 21, 1946, physicist Louis Slotin and seven other Los Alamos personnel were in a Los Alamos laboratory conducting another experiment to verify the closeness of the core to criticality by the positioning of neutron reflectors. Slotin, who was leaving Los Alamos, was showing the technique to Alvin C. Graves, who would use it in a final test before the Operation Crossroads nuclear tests scheduled a month later at Bikini Atoll. It required the operator to place two half-spheres of beryllium (a neutron reflector) around the core to be tested and manually lower the top reflector over the core using a thumb hole on the top. As the reflectors were manually moved closer and farther away from each other, scintillation counters measured the relative activity from the core. The experimenter needed to maintain a slight separation between the reflector halves in order to stay below criticality. The standard protocol was to use shims between the halves, as allowing them to close completely could result in the instantaneous formation of a critical mass and a lethal power excursion. Under Slotin's own unapproved protocol, the shims were not used and the only thing preventing the closure was the blade of a standard flat-tipped screwdriver manipulated in Slotin's other hand. Slotin, who was given to bravado, became the local expert, performing the test on almost a dozen occasions, often in his trademark blue jeans and cowboy boots, in front of a roomful of observers. Enrico Fermi reportedly told Slotin and others they would be "dead within a year" if they continued performing the test in that manner.[12] Scientists referred to this flirting with the possibility of a nuclear chain reaction as "tickling the dragon's tail", based on a remark by physicist Richard Feynman, who compared the experiments to "tickling the tail of a sleeping dragon".

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 blue light and a wave of heat across Slotin's skin; the core had become supercritical, releasing an intense burst of neutron radiation estimated to have lasted about a half second. Slotin quickly twisted his wrist, flipping the top shell to the floor. The heating of the core and shells stopped the criticality within seconds of its initiation,[15] while Slotin's reaction prevented a recurrence and ended the accident. The position of Slotin's body over the apparatus also shielded the others from much of the neutron radiation, but he received a lethal dose of 1,000 rad (10 Gy) neutron and 114 rad (1.14 Gy) gamma radiation in under a second and died nine days later from acute radiation poisoning. The nearest person to Slotin, Graves, who was watching over Slotin's shoulder and was thus partially shielded by him, received a high but non-lethal radiation dose. Graves was hospitalized for several weeks with severe radiation poisoning and developed chronic neurological and vision problems as a result of the exposure. He died 20 years later, at age 55, of a heart attack. It may have been caused by hidden complications from radiation exposure, but could also have been genetic in nature, as his father had died from the same cause.

https://en.wikipedia.org/wiki/Demon_core


From Wikipedia: A re-creation of the 1946 experiment. The half-sphere is seen, but the core inside is not. The beryllium hemisphere is held up with a screwdriver.


This video tells the whole story



"Have you paid your dues, Jack? Yessir, the check is in the mail."

Re: Have you ever heard about the demon core?

That's interesting. This makes me think of the Watchmen incident with Dr. Manhattan.

Re: Have you ever heard about the demon core?

This makes me think of the Watchmen incident with Dr. Manhattan.
Right?!

"Have you paid your dues, Jack? Yessir, the check is in the mail."

Re: Have you ever heard about the demon core?

I heard Michio Kaku talk about that on an episode of Art Bell, maybe a couple or more episodes. Pretty crazy to play with those things like they're toys. I was reading about nuclear accidents recently. Louis Slotin absorbed a big dose with 10 Gy but Cecil Kelley wins with 36 Gy.

Re: Have you ever heard about the demon core?

[…] but Cecil Kelley wins with 36 Gy.
Wow. I wasn't aware of that event. Thanks for mentioning it.

"Have you paid your dues, Jack? Yessir, the check is in the mail."

Re: Have you ever heard about the demon core?

Fascinating, and I had never heard of that before. The end of the video reminded me of the door sequence from MST3K.





Schrodinger's Cat walks into a bar, and doesn't. 😼

Re: Have you ever heard about the demon core?

We have to admit those guys had balls. Sloting was essentially operating a nuclear reactor with his bare hands and a screwdriver.

"Have you paid your dues, Jack? Yessir, the check is in the mail."

Re: Have you ever heard about the demon core?

Real men handled nuclear bomb material with no shirts on back in the day.

Harold,the singing angel harks.

Re: Have you ever heard about the demon core?

Yes, great big ones! So big that you could hear them clank when they walked!



Schrodinger's Cat walks into a bar, and doesn't. 😼
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