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It's all in the wiki: https://en.wikipedia.org/wiki/Demon_core https://en.wikipedia.org/wiki/Demon_core > It required the operator to place two half-spheres of

It's all in the wiki: https://en.wikipedia.org/wiki/Demon_core https://en.wikipedia.org/wiki/Demon_core > 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 at the polar point. As the reflectors were manually moved closer and farther away from each other, neutron detectors indicated the core's neutron multiplication rate. The experimenter needed to maintain a slight separation between the reflector halves to allow enough neutrons to escape from the core 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. > Because in my head, a proper experiment has data collection and precise measurements. In your head yes, in early nuclear science it seems protocols weren't that important as long as it went boom in the end. As with many industries, regulations are written in blood

dale_glass 2y ago
I've read that and it doesn't really answer those questions. How can you measure the core's neutron multiplication rate if you're not exactly controlling the distance? Isn't the measurement going to be all over the place?
- kstrauser 2y ago
  In a demonstration, not an experiment, it’s sufficient to have the Geiger counter go clicky at different rates while the demonstrator plays the sphere like a theremin. The point was to show it to people, not to collect data.
  - eichin 2y ago
    > plays the sphere like a theremin Wow, that's a brilliantly horrifying image. (Are there other analogous ones? Does anyone do musical timing of building demolitions, or something like that?)
    - Terr_ 2y ago
      I have the vague feeling like the last 40 years of movies must have contained at least one scene where a villainous figure makes conductor-motions as things explode to music, but I can't recall anything specific. There was the V For Vendetta movie where landmarks exploded to the 1812 Overture, but no gesturing was involved.
      - kstrauser 2y ago
        The forgettable “Virtuosity” had Russell Crowe doing something like that, but it was awful.
      - Terr_ 2y ago
        P.S.: I was wrong, the ending scene didn't have that because [spoiler omitted], but there's a much earlier scene [0] that fits the bill. [0] https://www.youtube.com/watch?v=VCaT6tU7V8Q https://www.youtube.com/watch?v=VCaT6tU7V8Q
      - account42 2y ago
        It's not just V For Vendetta, 1812 Overture is supposed to include explosions (artillery/cannon fire) in its composition.
    - deleted 2y ago
      [deleted]
- lm28469 2y ago
  It was a boy's club with unlimited funding working on things that were never attempted before, a lot of things weren't exactly done by the books, even their original "safe" protocol would seem completely insane by modern standards. As long as it went boom in the end and they kept it secret I doubt they had many rules
- michaelt 2y ago
  Imagine if you'd invented the world's first modern sink, in a world that had never seen a faucet or a plughole before. And you're training some new guys on the details of what you're working on. Sure, some of that training is going to involve blackboard calculations and careful measurements. But you're also probably going to demonstrate a sink to them and say "As you can see, when we turn this knob more hot water is added to the mix. Note how, after I put the plug in the plughole, the water level starts rising." The purpose of the demo isn't to precisely measure the depth of the water or the temperature at the faucet or the angle the tap is turned to. It's just to let them see the thing in practice, so as they study it in theory they know what to imagine and how the model maps onto the real world.
GTP 2y ago
Regardless of the outcome, this still looks like a poor demonstration: what's the point of showing how it is done, if you're not following the protocol anyway? My understanding is that those in the room where nuclear experts, so they didn't need a demonstration to know that, the closer the two cores where, the higher the radiation.
- SoftTalker 2y ago
  Same reason that chemistry professors demonstrate dramatic reactions in front of the class from time to time. It's fun, and keeps things interesting, even if you already know the chemical processes that are happening.
atomicnumber3 2y ago
I've read about this in a few different mediums before and no it's not just that protocols weren't that important. The guy doing this experiment was *notorious* for it and multiple other manhattan project people had already told him he was going to die if he kept doing it. But he had the kind of bravado and personality that he kept doing it. So to be clear: all of the other people whose risk tolerance levels already had them handling weapons-grade plutonium as a career ALSO thought this guy was insane for doing this.
- vundercind 2y ago
  He took a dip in a pool with a functioning nuclear pile some time before that just to avoid having to shut the thing down before doing some maintenance, taking a pretty big dose. He was a daredevil and had the kind of bravado of someone on a work site who scoffs at PPE and rolls their eyes when you tell them they need to wear a damn helmet. Those types usually end up having a bad time eventually.
  - gopher_space 2y ago
    > Those types usually end up having a bad time eventually. It's entirely possible to build up skills allowing you to avoid using PPE, but every kid who sees you is being put at risk just so you can swing your dick around.
    - quickthrowman 2y ago
      No it isn’t. Over an 80,000 hour career in construction/other dangerous field, you will eventually have an incident that will make you thankful for PPE.
    - 0x457 2y ago
      > It's entirely possible to build up skills allowing you to avoid using PPE Yes, but you only need to mess up once and your skill doesn't save you from other people mistakes.
    - MeetingsBrowser 2y ago
grecy 2y ago
Another thing I've always wondered - what would have happen if everyone in the room freaked out and just ran away, leaving the two reflector halves completed closed? Would it have actually gone bang like a bomb, or more like just get insanely hot and give off an insane amount of radiation, but over the span of many seconds?

dale_glass 2y ago

I've read that and it doesn't really answer those questions. How can you measure the core's neutron multiplication rate if you're not exactly controlling the distance? Isn't the measurement going to be all over the place?

kstrauser 2y ago
In a demonstration, not an experiment, it’s sufficient to have the Geiger counter go clicky at different rates while the demonstrator plays the sphere like a theremin. The point was to show it to people, not to collect data.
- eichin 2y ago
  > plays the sphere like a theremin Wow, that's a brilliantly horrifying image. (Are there other analogous ones? Does anyone do musical timing of building demolitions, or something like that?)
  - Terr_ 2y ago
    I have the vague feeling like the last 40 years of movies must have contained at least one scene where a villainous figure makes conductor-motions as things explode to music, but I can't recall anything specific. There was the V For Vendetta movie where landmarks exploded to the 1812 Overture, but no gesturing was involved.
    - kstrauser 2y ago
      The forgettable “Virtuosity” had Russell Crowe doing something like that, but it was awful.
    - Terr_ 2y ago
      P.S.: I was wrong, the ending scene didn't have that because [spoiler omitted], but there's a much earlier scene [0] that fits the bill. [0] https://www.youtube.com/watch?v=VCaT6tU7V8Q https://www.youtube.com/watch?v=VCaT6tU7V8Q
    - account42 2y ago
      It's not just V For Vendetta, 1812 Overture is supposed to include explosions (artillery/cannon fire) in its composition.
  - deleted 2y ago
    [deleted]
lm28469 2y ago
It was a boy's club with unlimited funding working on things that were never attempted before, a lot of things weren't exactly done by the books, even their original "safe" protocol would seem completely insane by modern standards. As long as it went boom in the end and they kept it secret I doubt they had many rules
michaelt 2y ago
Imagine if you'd invented the world's first modern sink, in a world that had never seen a faucet or a plughole before. And you're training some new guys on the details of what you're working on. Sure, some of that training is going to involve blackboard calculations and careful measurements. But you're also probably going to demonstrate a sink to them and say "As you can see, when we turn this knob more hot water is added to the mix. Note how, after I put the plug in the plughole, the water level starts rising." The purpose of the demo isn't to precisely measure the depth of the water or the temperature at the faucet or the angle the tap is turned to. It's just to let them see the thing in practice, so as they study it in theory they know what to imagine and how the model maps onto the real world.

GTP 2y ago

Regardless of the outcome, this still looks like a poor demonstration: what's the point of showing how it is done, if you're not following the protocol anyway? My understanding is that those in the room where nuclear experts, so they didn't need a demonstration to know that, the closer the two cores where, the higher the radiation.

SoftTalker 2y ago
Same reason that chemistry professors demonstrate dramatic reactions in front of the class from time to time. It's fun, and keeps things interesting, even if you already know the chemical processes that are happening.

atomicnumber3 2y ago

I've read about this in a few different mediums before and no it's not just that protocols weren't that important. The guy doing this experiment was *notorious* for it and multiple other manhattan project people had already told him he was going to die if he kept doing it. But he had the kind of bravado and personality that he kept doing it. So to be clear: all of the other people whose risk tolerance levels already had them handling weapons-grade plutonium as a career ALSO thought this guy was insane for doing this.

vundercind 2y ago
He took a dip in a pool with a functioning nuclear pile some time before that just to avoid having to shut the thing down before doing some maintenance, taking a pretty big dose. He was a daredevil and had the kind of bravado of someone on a work site who scoffs at PPE and rolls their eyes when you tell them they need to wear a damn helmet. Those types usually end up having a bad time eventually.
- gopher_space 2y ago
  > Those types usually end up having a bad time eventually. It's entirely possible to build up skills allowing you to avoid using PPE, but every kid who sees you is being put at risk just so you can swing your dick around.
  - quickthrowman 2y ago
    No it isn’t. Over an 80,000 hour career in construction/other dangerous field, you will eventually have an incident that will make you thankful for PPE.
  - 0x457 2y ago
    > It's entirely possible to build up skills allowing you to avoid using PPE Yes, but you only need to mess up once and your skill doesn't save you from other people mistakes.
  - MeetingsBrowser 2y ago

grecy 2y ago

Another thing I've always wondered - what would have happen if everyone in the room freaked out and just ran away, leaving the two reflector halves completed closed? Would it have actually gone bang like a bomb, or more like just get insanely hot and give off an insane amount of radiation, but over the span of many seconds?