Nu-Klear Fallout Detector (ca. 1962-1968) | Hacker News Reader

Nu-Klear Fallout Detector (ca. 1962-1968)

orau.org

80 pointscryptoz21 comments

There's a short fictional account of a science teacher constructing a gold leaf electroscope using stuff in the school, and plaster dug out of the wall of the classroom to help map radioactivity after a limited-strike nuclear war, in "Warday" by Whitley Strieber & James Kunetka. (at least one of these authors has a bit of a nutty back-story, It's important to remember the book lies solidly in the realms of fiction)

I always thought it was somewhat fantastical. I'm rather delighted they could have beaded some polystyrene and stuck it in a cup for much the same effect.

Several SF novels mention using scintillation plastic. Is that also simply fantasy, or are there passive scintillation meters which could in fact detect levels of radioactivity? The 1900s models demanded 20 minutes of acclimatisation inside a dark chamber and were notoriously hard to use. Rutherford refused to use a counter while he could show his trained workers (women mainly) were as accurate. Those counters were photomultiplier tubes. I think quite a lot of the tech here was a precursor to TV, and ultimately the CCD in some ways.

Filmstrip exposure would tell you about a lethal dose, after the event. Helpful for budding scientists if they have enough lab rats to send out with a chunk of film in a wrapper.

Polyvinyl toluene is scintillation plastic.

Not the same thing, but had me remembering the "official" way of disposing of toluene after Chemistry lab in my US High School.

Carefully carry it to the window overlooking the lower roof. Toss it on the roof. Let it evaporate.

We poured ours down the drain.

Sounds like youre looking for the Kearny Fallout Meter:

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

Scintillation plastic is very much a thing. Big accelerators, like CERN or Fermilab, used to use long, floppy strips of plastic attached to a photomultiplier tube, which goes to the counters. I believe they still use scintillator detectors farther from the collision region, but the trend has been to move towards silicon pixel detectors closer in.

One thing with scintillators though: You're typically detecting a few photons at a time, so a photomultiplier tube (PMT) is really required for any kind of reasonable SNR with any kind of reasonable temporal resolution.

> Those counters were photomultiplier tubes.

A PMT is actually not a counter (but they are normally used with a counter). It's just a transducer that produces electrical charge at the output in response to photons at the input.

Normally the PMT is connected to a "discriminator" (very fast voltage threshold detector, with adjustable threshold(s)) which takes the very narrow pulses (~2-3 ns) from the PMT and stretches them into pulses with fixed rise time, width and voltage. Those pulses are then counted using whatever hardware you can dream up.

A PMT is really just an electron multiplier with a photocathode in front, so you have all the same issues as you do with electron multipliers and thus use a discriminator for all the same reasons (mainly to remove "runt pulses" that didn't originate from a photon at the input window). Normally you'd use a single level discriminator, but "multi-channel" ones exist also.

Having an adjustable threshold on the discriminator is important to maximize SNR because the electron multiplier within the PMT will wear out and produce smaller pulses, and there can be significant variation in pulse size across serial numbers.

> Rutherford refused to use a counter while he could show his trained workers (women mainly) were as accurate.

I'm skeptical of this account, and the only thing I can find with a quick Google is that Rutherford hired women to count scintillation events because he could pay them less than men(-counters).

Theodore Gray has one of these in his periodic table. This quote stood out to me:

"I've held this thing up to the strongest sources of radiation I have and the balls don't budge... I think it's safe to say that if you do ever see the balls drop, you should run, not walk, to wherever you think there might be less radiation around."

https://theodoregray.com/PeriodicTable/Samples/094.4/index.s...

This website design is absurd and I love it. It works really well as a document but the skeumorph of it being a physical periodic table with samples that's also a wooden desk gets so disconnected from a physical metaphor as you drill in. Like, my desk has a zoom control?

It has that feeling of hand spun websites from the aughts maintained with such care, like a curio cabinet. It's been a long time since I just clicked around one of these. There's a lot to be said for the simple and minimalistic designs that are more conventional today, and I'm going to continue laying out my HTML that way, but in comparison they're woefully lacking in character.

We had one of these in the house when I was a kid in the 90s. Seriously wild to learn what it was when I was like 12, after some years of not understanding ha. Never really was sure if it would work or not.

Sadly the article doesn't say if they actually work or whether they are snake oil.

Poking around I found this video, where a university professor demonstrates the principle with a snow globe (containing virtually the same beads) and a strontium 90 source.

https://youtube.com/watch?v=3kHfXntPMoI

I think they would work as advertised. I'm not sure that makes them entirely not snake oil, though.

Why not buy a normal radiometer? They are so cheap and mass produced.

These days digital integrating radiometers are able to not just integrate dose over time, but also adjust for dose rate effects (i.e. same amount radiation absorbed over shorter time is more harmful), and ratio of beta, gamma, and neutrons. And they cost in the range of $200. I still keep my CD V-715 somewhere in the closet, though.

The “prepper” mindset was rampant in the 1960s because of uncertainty and fear around nuclear war. Radiation detectors would have been still costly for the average Joe, and this allowed people to feel some level of preparedness.

> and this allowed people to feel some level of preparedness.

I can imagine it now:

"I can now afford to buy a device that will inform me if I'm about to die"

It's hideous but it's a sort of psychology that makes sense to me. You're faced with this overwhelming existential threat you can't really understand. And here's a cute consumer device marketed to you to that promises to give you some idea what might be happening. It's a way of establishing the feeling of control, even if it doesn't work very well.

No, having some radiation indicating device is a lot better than not having one. It at least shows when it's safe to leave your basement for a short while or not.

I managed to find two of the missing patents mentioned on that page, because there's a picture of a device with four patent numbers on it.

https://patents.google.com/patent/US3093737A/en?oq=3093737

According to the patent Walter Shriner was based in Springfield, Illinois, which was mentioned as "ground zero" for these devices.

Shriners patent references the older 568 patent by Failla, who assigned it to the Atomic Energy Commission.

https://patents.google.com/patent/US2731568A/en?oq=2731568

Accounting for inflation, the advertised price for one of these would of been roughly $240!

I once built an advertising efficacy detector. It was a voltmeter connected to a solar cell. The more light there was in a shop window, the stronger its advertising effect.

Does this detector work equally well?

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