11 ms·

I think the core of the explanation given is correct but some of the adjacent details need adjustment. The important part is: "Clothes dryers are very effectiv

I think the core of the explanation given is correct but some of the adjacent details need adjustment. The important part is: "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?s=20 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. :)

deleted 3y ago
[deleted]
kloch 3y ago
> but they are highly sensitive to beta 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?
- BetterGeiger 3y ago
  Beta particles are basically energetic electrons flying around, yes, but for a Geiger counter to detect them they have to be quite energetic in order to penetrate the Geiger tube itself (detection occurs essentially inside the tube, in the gas)... So I doubt that static field is generating electrons anywhere near that energy needed to be detected by a Geiger tube.
  - deleted 3y ago
    [deleted]
  - kloch 3y ago
    Dryer static charges are probably a few keV at most so yeah that shouldn't make it through a metal envelope. 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.
dogben 3y ago
My geiger counter activity goes up when air conditioner is working. Never figured out why. This could be a good explanation.
- Cerium 3y ago
  Is your interior AC unit or its ducting in a basement or crawlspace?
  - dogben 3y ago
    It's interior. No ventilation. I guess it's ionizing the air and bringing radioactive dust particles to the whole room. The radiation level is still very low so I'm not worried.
- detrites 3y ago
  Does your AC include a negative ion generator for cleaning the air? I wonder if that could be affecting it?
  - dogben 3y ago
    I don't think it has negative ion generator. I guess the fan itself can generate ions, that's why aircraft have static dischargers.
antognini 3y ago
> hobbyist grade detectors (Geiger tubes) are not sensitive to alpha but they are highly sensitive to beta and a little sensitivity to gamma. 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.)
- BetterGeiger 3y ago
  Yes, and even if you have a high-end alpha detector, ingested radioactive material cannot be detected externally if it's only emitting alpha. One would need to take a blood sample or something like that and do more complicated tests.
- jxf 3y ago
  How did it get detected?
  - antognini 3y ago
    His symptoms were consistent with radiation poisoning and because he was a high profile dissident his case attracted enough attention that the Atomic Weapons Establishment tested his blood and urine. 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.
    - codethief 3y ago
      > 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 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/toi/radSearch.asp https://web.archive.org/web/20150408041531/http://ie.lbl.gov...
K2h 3y ago
$149 for https://www.bettergeiger.com/product-list/p/better-geiger-radiation-detector https://www.bettergeiger.com/product-list/p/better-geiger-ra...
- ilyt 3y ago
  I'm mildly disappointed that banana is not listed as option for test material
  - Turskarama 3y ago
    Even though bananas are famously radioactive, it's very low activity and I don't know that a regular detector could pick up the emissions from a single banana. You'd probably need a truck full of them.
    - kneebonian 3y ago
      For those curious about the radioactivity of bananas. https://what-if-origin.sciesnet.net/158/ https://what-if-origin.sciesnet.net/158/
  - BetterGeiger 3y ago
    haha, yes... unfortunately they emit such an extremely tiny amount you can't measure it with ordinary means, I tried: https://twitter.com/BetterGeiger/status/1523769482602196992 https://twitter.com/BetterGeiger/status/1523769482602196992
thadt 3y ago
Hey, that's a pretty slick package (and price point). I looked through bettergeiger.com and read the discussion about the difference between GM tubes vs scintillators, but never saw an indication of what material you're using. Would be useful information for those of us thinking of upgrading from an SBM-20.
- BetterGeiger 3y ago
  I'm sorry to say that some of the sensor design details, including material and geometry, are not shared. That was a critical optimization process during the design phase (tricky balancing act between cost and performance) and I want to slow down any copy-cat devices. However in terms of performance I am pretty open and detailed about how the device actually behaves: https://twitter.com/BetterGeiger/status/1475480971050901511 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.
thewanderer1983 3y ago
>What that commenter misses is that nearly all hobbyist grade detectors (Geiger tubes) are not sensitive to alpha 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.
- Turskarama 3y ago
  Could also be a happy accident though. Half an hour is short enough that the amount of radiation emitted is pretty high, but long enough that it hasn't pretty much all decayed by the time you try to measure it.
- BetterGeiger 3y ago
  You are right, the commenter implied that.
ZeroCool2u 3y ago
I have absolutely no need for your product, but I do want one and fully intend to gift them to others now. Great little device, awesome work.
- BetterGeiger 3y ago
  Thank you! Most people don't need one (and hopefully it stays that way) but I still think it's a fun and educational device. If nothing else it's a conversation piece. :)
nocoiner 3y ago
Man, so glad I decided to finally click on the comments after seeing the article at the top of hn most the day - we don’t have radon where I live (I don’t think?) so I figured the dryer thing wasn’t applicable to me. 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.
- BetterGeiger 3y ago
  Fantastic! Let me know if you have any questions... and be sure to find a current 12 year old kid to plant the seed of interest in radiation. :)
- hermitdev 3y ago
  What's NPP here?
  - S3rM5Y5 3y ago
    Nuclear Power Plant
jve 3y ago
What's the difference between alpha/beta/gamma and which is of concern?
- _Algernon_ 3y ago
  Alpha has the shortest range and can be blocked by a piece of paper. Alpha radiation consists of protons. 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.
  - EntropicHeaven 3y ago
    > Alpha radiation consists of protons. 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)

deleted 3y ago

[deleted]

kloch 3y ago

> but they are highly sensitive to beta 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?

BetterGeiger 3y ago
Beta particles are basically energetic electrons flying around, yes, but for a Geiger counter to detect them they have to be quite energetic in order to penetrate the Geiger tube itself (detection occurs essentially inside the tube, in the gas)... So I doubt that static field is generating electrons anywhere near that energy needed to be detected by a Geiger tube.
- deleted 3y ago
  [deleted]
- kloch 3y ago
  Dryer static charges are probably a few keV at most so yeah that shouldn't make it through a metal envelope. 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.

dogben 3y ago

My geiger counter activity goes up when air conditioner is working. Never figured out why. This could be a good explanation.

Cerium 3y ago
Is your interior AC unit or its ducting in a basement or crawlspace?
- dogben 3y ago
  It's interior. No ventilation. I guess it's ionizing the air and bringing radioactive dust particles to the whole room. The radiation level is still very low so I'm not worried.
detrites 3y ago
Does your AC include a negative ion generator for cleaning the air? I wonder if that could be affecting it?
- dogben 3y ago
  I don't think it has negative ion generator. I guess the fan itself can generate ions, that's why aircraft have static dischargers.

antognini 3y ago

> hobbyist grade detectors (Geiger tubes) are not sensitive to alpha but they are highly sensitive to beta and a little sensitivity to gamma. 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.)

BetterGeiger 3y ago
Yes, and even if you have a high-end alpha detector, ingested radioactive material cannot be detected externally if it's only emitting alpha. One would need to take a blood sample or something like that and do more complicated tests.
jxf 3y ago
How did it get detected?
- antognini 3y ago
  His symptoms were consistent with radiation poisoning and because he was a high profile dissident his case attracted enough attention that the Atomic Weapons Establishment tested his blood and urine. 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.
  - codethief 3y ago
    > 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 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/toi/radSearch.asp https://web.archive.org/web/20150408041531/http://ie.lbl.gov...

K2h 3y ago

$149 for https://www.bettergeiger.com/product-list/p/better-geiger-radiation-detector https://www.bettergeiger.com/product-list/p/better-geiger-ra...

ilyt 3y ago
I'm mildly disappointed that banana is not listed as option for test material
- Turskarama 3y ago
  Even though bananas are famously radioactive, it's very low activity and I don't know that a regular detector could pick up the emissions from a single banana. You'd probably need a truck full of them.
  - kneebonian 3y ago
    For those curious about the radioactivity of bananas. https://what-if-origin.sciesnet.net/158/ https://what-if-origin.sciesnet.net/158/
- BetterGeiger 3y ago
  haha, yes... unfortunately they emit such an extremely tiny amount you can't measure it with ordinary means, I tried: https://twitter.com/BetterGeiger/status/1523769482602196992 https://twitter.com/BetterGeiger/status/1523769482602196992

thadt 3y ago

Hey, that's a pretty slick package (and price point). I looked through bettergeiger.com and read the discussion about the difference between GM tubes vs scintillators, but never saw an indication of what material you're using. Would be useful information for those of us thinking of upgrading from an SBM-20.

BetterGeiger 3y ago
I'm sorry to say that some of the sensor design details, including material and geometry, are not shared. That was a critical optimization process during the design phase (tricky balancing act between cost and performance) and I want to slow down any copy-cat devices. However in terms of performance I am pretty open and detailed about how the device actually behaves: https://twitter.com/BetterGeiger/status/1475480971050901511 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.

thewanderer1983 3y ago

>What that commenter misses is that nearly all hobbyist grade detectors (Geiger tubes) are not sensitive to alpha 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.

Turskarama 3y ago
Could also be a happy accident though. Half an hour is short enough that the amount of radiation emitted is pretty high, but long enough that it hasn't pretty much all decayed by the time you try to measure it.
BetterGeiger 3y ago
You are right, the commenter implied that.

ZeroCool2u 3y ago

I have absolutely no need for your product, but I do want one and fully intend to gift them to others now. Great little device, awesome work.

BetterGeiger 3y ago
Thank you! Most people don't need one (and hopefully it stays that way) but I still think it's a fun and educational device. If nothing else it's a conversation piece. :)

nocoiner 3y ago

Man, so glad I decided to finally click on the comments after seeing the article at the top of hn most the day - we don’t have radon where I live (I don’t think?) so I figured the dryer thing wasn’t applicable to me. 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.

BetterGeiger 3y ago
Fantastic! Let me know if you have any questions... and be sure to find a current 12 year old kid to plant the seed of interest in radiation. :)
hermitdev 3y ago
What's NPP here?
- S3rM5Y5 3y ago
  Nuclear Power Plant

jve 3y ago

What's the difference between alpha/beta/gamma and which is of concern?

_Algernon_ 3y ago
Alpha has the shortest range and can be blocked by a piece of paper. Alpha radiation consists of protons. 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.
- EntropicHeaven 3y ago
  > Alpha radiation consists of protons. 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)