It's all in the wiki: 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

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.

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.

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?

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?