I’m not familiar with Geiger counter design/specs but would the considerable static electricity send some electrons into the detector and cause a false positive beta hit?
However, I wonder how well shielded the electronics are. In a poor quality design even the static charge fields themselves might trigger a false hit.
This was part of the reason why it took so long to discover the cause of Alexander Litvinenko's death by Polonium-210 poisoning. Doctors (and later detectives) had suspected some form of radiation poisoning, but the early tests used Geiger counters and came back negative. But Po-210 decays almost exclusively by emitting an alpha particle which is not detectable by Geiger counters. (And it also means it's not very dangerous outside the body but becomes extremely toxic if ingested.)
They performed gamma ray spectroscopy but did not discover any strong signals, except for a very small spike at 803 keV. Some of the scientists were talking about the case and they were overheard by an older scientist who had worked on the UK's atomic weapons program back in the 50s. The early bombs relied on Po-210 and he recognized that 803 keV line as being characteristic of Po-210. Although the decay is almost exclusively via alpha particles, a very small fraction of decays happen via emission of a gamma ray at 803 keV.
Once they had the connection to Po-210 it was straightforward to test for its presence in his body.
I don't understand. So professionals from the AWE tried to identify the measured radiation lines from memory(?!), instead of consulting a publicly available database of spectral & decay lines? It's been a while since I've done any spectral analysis but I used to use ie.lbl.gov a lot (seems offline unfortunately) and they had a search function[0] that allowed you to filter their entire database of isotopes and decay chains by whatever line you were looking for.
[0]: https://web.archive.org/web/20150408041531/http://ie.lbl.gov...
https://www.argonelectronics.com/blog/litvinenko-and-the-per...
Also, from the article:
> The UK Health Protection Agency, which is advising authorities on technical aspects of the case, characterises the contamination in all 12 cases as “not significant enough to result in any illness in the short term,” while “any increased risk in the long term is likely to be very small.”
"An antistatic fan made by NRD, of Grand Island, N.Y., contains 31,500 microcuries of polonium 210 — or, in theory, more than 10 lethal doses."
Source: https://www.nytimes.com/2006/12/03/weekinreview/03broad.html
https://twitter.com/BetterGeiger/status/1475480971050901511
Another metric some people like is CPM/[uSv/hr] when exposed to Cs-137 (662 keV). That number is about 415, whereas cheapo Geigers can be as low as 10, and decent consumer-grade Geiger counters are usually around 120. This number gives a decent idea about relative X-ray/gamma sensitivity of those devices.
from the original post: "If your Geiger counter is actually detecting radiation, it's almost certainly the half-hour lead and bismuth. " If you look at the table he provided lead and bismuth are beta decay. It is likely he is specifying that on the fact that most home geiger counters only detect beta and gamma not alpha.
But for the vast majority of my life, I’ve always wanted a Geiger counter, and once they were cheap and readily available on Amazon, I was just about to pull the trigger. And then Fukushima happened a week later and sent prices into the stratosphere.
A few times recently I idly looked at the ones on Amazon but never got around to it because I couldn’t tell which were junky crap and which were somewhat more expensive junky crap.
But very cool to see a knowledgeable manufacturer explaining his product in a highly relevant comment thread. Finally, the radiation detector for me!
There’s a former 12 year old kid out there who still remembers the Geiger counter exhibit from taking a pre-9/11 NPP tour who’s going to be very excited for something coming in the mail in the next week or two.
Gamma goes through most things and has the highest range. Gamma consists of electro magnetic radiation.
Beta is somewhere in the middle. It consists of electrons.
All are of concern, but Alfa is mainly of concern if ingested or inhaled. This is because all the radiation will be absorbed by your body, while most gamma would just escape. Gamma is of more concern outside the body, due to its reach.
I may remember some details wrong. I last learned about this in school a decade ago.
Alpha radiation is helium-4 nucleus - two protons and two neutrons.
> Beta is somewhere in the middle. It consists of electrons.
Beta is either electron (β− decay) or positron (β+ decay)
"Clothes dryers are very effective at making statically charged surfaces. (Dryer sheets help.) So when radon and its temporary decay products are blown through the dryer, electrically-polarized molecules tend to be attracted to the charged surfaces"
What that commenter misses is that nearly all hobbyist grade detectors (Geiger tubes) are not sensitive to alpha but they are highly sensitive to beta and a little sensitivity to gamma. However, any thin solid will block beta, so they would need the Geiger tube to be very near the radiation emitting material to pick up the beta. In other words, if they're just waving the detector around they're probably just catching the gamma.
The radon in the air decays into various progeny, and by the time it reaches the dryer that will be to some extent in equilibrium, so several isotopes, including gamma emitters, will be present in the mix. Therefore I'm not surprised the detector reads a tiny bit of that.
Why it dissipates is probably not a decay thing but rather the accumulated material gradually diffusing away from the filter or whatever after the dryer is turned off and no longer actively accumulating radon.
This could be tested by putting a detector right next to the filter to see how much beta it picks up. I've basically done that with a home air filter:
https://twitter.com/BetterGeiger/status/1605639346865901570?...
That's with the detector I make and sell which is primarily sensitive to gamma, which is why I could register a reading through the plastic container, even a couple days after preparing the test. When I used a pancake style detector sensitive to alpha and beta, directly against the exposed filter, the detector reacted much more strongly... But the Better Geiger S-1 gives an accurate dose reading, the Geiger tube or pancake probe will dramatically overestimate dose in that scenario, which can cause undue concern... In reality it's pretty harmless levels of radiation. :)