Why is my dryer radioactive?
physics.stackexchange.com
physics.stackexchange.com
"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. :)
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.)
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
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...
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.
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.
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.
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.
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)
https://physics.stackexchange.com/questions/121830/does-eart... There is no tidal bulge
I'd love for you to explain what you mean by this. Either you're mistaken or I'm about to learn something really interesting. Here's a link a quick search brought me, for reference. Are you talking about something other than refractive index, ratios of c, and prisms? Like a latency metric of some kind? I'm very curious.
https://en.wikipedia.org/wiki/Speed_of_light#:~:text=For%20e....
I'm still confused. How is it an inaccurate simplification to state that the speed of light in glass is lower than in a vacuum?
red75prime's short answer in this thread is correct, for a longer one see this Physics SE questions and answers (https://physics.stackexchange.com/questions/11820/what-reall...). In ELI5 terms: photons always move at speed c, but in a medium now and then (depending on properties of the medium, density, etc.) they interact with its atoms. In this case the atom absorbs the photon and after a short time generates another photon. So the speed of each photon is always c but the "overall light wave" becomes less than c.
If you're a non physicist like me who would like to delve further into this, I suggest Feynman's excellent and very readable book QED: The Strange Theory of Light and Matter (https://www.amazon.com/QED-Strange-Theory-Light-Matter/dp/06...)
I understand what you're saying, and don't disagree that the quantum electrodynamics treatment is a theoretical model that can describe optical phenomena, but I guess I'm a little nonplussed when you compare tidal theory to optical theory.
Newton's theory of tides was incorrect; it does not accurately predict tidal phenomena[0]. Using classical EM field theory with refractive indices and ratios of c is not incorrect; it gives accurate predictions of optical phenomena at the macroscopic scale. It's certainly incomplete, but not inaccurate.
I think the disconnect might be that when studying physics, it gets drilled into you over and over that no model is right or wrong, just applicable or inapplicable to a given situation. For example, here's a passage in Griffiths' Introduction to Electrodynamics:
"In fact, when you stop to think about it, the electric field inside matter must be fantastically complicated, on the microscopic level. If you happen to be very near an electron, the field is gigantic, whereas a short distance away it may be small or point in a totally different direction. Moreover, an instant later, as the atoms move about, the field will have altered entirely. This true microscopic field would be utterly impossible to calculate, nor would it be of much interest if you could. Just as, for macroscopic purposes, we regard water as a continuous field, ignoring its molecular structure, so also we can ignore the microscopic bumps and wrinkles in the electric field inside matter, and concentrate on the macroscopic field. This is defined as the average field over regions large enough to contain many thousands of atoms (so that the uninteresting microscopic fluctuations are smoothed over), and yet small enough to ensure that we do not wash out any significant large-scale variations in the field. Ordinarily, the macroscopic field is what people mean when they speak of "the" field inside matter. (In case the introduction of the macroscopic field sounds suspicious to you, let me point out that you do exactly the same averaging whenever you speak of "the" field inside matter.)"
So I guess I'm saying that the physical intuition and mental models used to work with classical EM field theory are different fom those used to work with quantum theories is just part of what it means to be a physicist.
Anyway, I'm glad you're so excited about physics! If you liked QED, you might be interested in Schroedinger's "What is Life?", where he takes his experience from quantum physics to speculate on how the information-theoretical requirements of genetic inheritance in reproduction implies the existence of some sort of "aperiodic crystal" that encodes genetic information, decades before Crick & Watson discovered DNA. It's written for the layman, although it's not as readable as Feynman (although he's in a class of his own when it comes to scientific explanations).
Also, thanks for your original comment, because it gave me an opportunity to pull out some of my old textbooks and leaf through them for a while.
[0] My mental model of tidal phenomena corresponded to Newton's theory, so I found it fascinating how incomplete and inaccurate it is, prompting a long diversion down a Wikipedia rabbit-hole, to the point that I'm now considering giving a short lecture on tides at my birthday party in a couple weeks.
The part that is wrong is that the actual water level is nowhere near equilibrium, because the moon moves. In fact, the water level doesn't even approximate this equilibrium but can (and does!) behave very differently.
For all practical purposes it's true. You'll get higher delays in fiber optics than in, say, radio-relay links. The details of matter-photon interaction are interesting, of course.
An astonishing amount of what we each believe is plain wrong, especially when we have little stories about it.
If you could do a perfect job of training a GPT on the entirety of published academic literature, the total of what that GPT could spit out would be limited by the knowledge contained in academic literature. At the same time, you'd have created a tool that is cheap and does a good job of synthesizing knowledge/answering questions across all disciplines. The model will never replace the scientists who are working at the very bounds of their fields, but it doesn't have to in order to be extremely useful, even useful enough to replace a majority of knowledge workers.
Just because GPTs can't be smarter than the smartest humans doesn't mean they can't be smarter than most humans.
Or perhaps the insight isn't trivial but follows analagous reasoning from some other obscure result. Or perhaps a million other things.
I don't mean to claim GPT will do this. I just mean to point out it can't be fully excluded GPT is able to.
why?
Hilarious
In my experience that is worth even more than a very high salary for your quality of life.
(That 1958 article morkalork dug up and presented below, seems historically interesting at least. Thanks for making an effort to show it.)
>Although the town is trim and neat, With cozy houses on every street, Though saying so is indiscreet,
>I hate it.
From: https://web.archive.org/web/20201126185123/https://archive.m...
https://www.science.org/content/article/near-disaster-federa...
So, if it attracts radon, does it raise the risk profile of the person? Should I ban sitting on static-electricity objects in radon-sensitive areas?
(Los Alamos doesn't have dangerous concentrations of radon; they just have very sensitive detectors.)
> ONE TIME I GOT RADON ON MY BUTT
Poured slabs are less permeable, not a low point, and tend to have better ventilation either intentionally or unintentionally.
In particular I think his scientific explanations aren't always fully accurate, and he worries about measurement minutia very strenuously. Also at one point he says you could breathe 80% radon/20% oxygen, which while chemically this is true, radiologically it would be suicidal.
Those nitpicks aside, his point about the EPA LNT model having no clothes is spot on. After "the scales fell from my eyes," now I can't not notice how all those same Party Line Claims get parroted in every piece of radon-related content.
Another glimpse down the rabbit hole is this interview with the late Dr Bernie Cohen, who studied the link between residential radon and cancer:
No, the alternative is to use real data, rather than fabricate fraudulent data to fit the LNT model.
Namely, you need to look at the actual shape of the dose-response curve in the real world, instead of externally imposing a certain predetermined shape by fiat and fudging data to fit.
Here's one of the relevant timestamps from the talk, which runs on into Part 3.[0] However if I'm being honest, this talk is impossible to capture in a short clip suitable for modern attention spans. My apologies.
To keep from getting lost, one really should watch the whole thing before formulating the next counterpoint. Otherwise this will devolve into a very long and boring comment thread, where I laboriously digest the points from the video and feed them to you through an HN comment-sized straw. ;)
This is why the NRC recently rejected a call to stop using LNT in setting regulations. Their responses to the details of the petitions are pretty damning.
https://www.regulations.gov/document/NRC-2015-0057-0671
Now, at the very low doses typical of large scale exposure from nuclear accidents, it's true that the evidence does not directly require LNT. That's because the effect predicted by LNT is so small at those doses that it's swamped by noise and unmodelled biases. No practically obtainable data could do the trick.
But note what this means: the data at those low doses is so poor that it's consistent with an effect greater than from LNT. It cannot rule this out.
I'll add that a favorite pseudoscientific claim from the radiation apologists, radiation hormesis, would imply a larger effect from radiation at low doses than predicted by LNT. That's because hormesis putatively acts by inducing repair mechanisms above some dose, bending the curve downward. Below that putative threshold, the curve has a high slope (and thus more damage per increment of dose) than the linear curve of the LNT.
This matches exactly what the presenter says: LNT makes great policy. It's just bad science, which the NRC demonstrates here by immediately throwing the LNT under the bus when questioned.
The NRC is literally calling LNT an "assumption" here. How much more of a hint do you need?
>The 1991 final rule explained that the NRC based its radiation protection regulations upon three assumptions. The first assumption concerned the use of the LNT model, which was described as follows:
>The first assumption, the linear nonthreshold dose-effect relationship, implies that the potential health risk is proportional to the dose received and that there is an incremental health risk associated with even very small doses
Policy has to go beyond what is rigorously demonstrated. It's not like criminal law. Technologies are not innocent until proven guilty. Just because LNT cannot be demonstrated at the doses relevant to nuclear accidents doesn't mean regulators should assume no effect.
>Policy has to go beyond what is rigorously demonstrated.
Thanks. I can see we're done here.
But at least you can admit LNT is consistent with the evidence? The claim to the contrary is an outright lie.
Large numbers of people get diagnosed with lung cancer; smoking rates vary widely and smoking is typically recorded in patient histories; typical radon levels vary widely with geography and are recorded / known. This looks like a near perfect natural experiment, no?
Caveat: the interviewer strikes me as quite flakey, but his reactions highlight how grounded Dr Cohen was.
In the south, Radon "can" be an issue, but it simply isn't an issue. In New England, it is often an issue.
There's more to the south than Texas, y'know. I can't recall if radon tests are required during a home inspection here in NC, or just highly recommended, but when I was buying a house last year I toured several homes that had radon mitigation systems installed.
But I think another factor has to do with the water table. In some places the water table rises high enough to flood basements, so you don't usually have basements at all in those places, and subsequently you don't have large reservoirs of radon adjacent to living spaces. I know of some people here in CO (where we have decaying granite in the soil) that don't have a basement and still need a radon ventilator, but it's not very common.
...but if you ever get annoyed by the whir of the fan, unplug it for a month and do an alpha-track monitor. (Or get a continuous monitor, they're cheap now!) There's every chance that simply having the cracks caulked and the piping in place, might do the trick all on its own, with no need for active depressurization.
Costs were around $2,000 CAD to install a sub-slab depressurization system (i.e. a fan that pulls air from below the house and vents it away from the house).
Radon values dropped from around 500 Bq/m3 to less than 20 Bq/m3.
We also had to dig trenches to lay natural gas lines, but we have a way to do those with horizontal boring techniques (of course then people who didn't know what they were doing put them straight through sewer lines, causing backups, visits from the Roto Rooter man, and subsequent explosions due to dumping natural gas straight into the sewer main).
Is it safe to assume they're using something like that with perforated pipes to exhaust radon?
Before going with active depressurization, start by installing a sealed sump cover, caulking the basement wall-to-floor joint, and caulking all the cracks in the basement walls, in that order. If that doesn't get the number down where you want it, drill the subslab access hole and install the ventilation piping to the outdoors, but don't install the fan in the middle. Only of those fail to get adequate results, install the fan.
It's really simple and quite cheap. I don't think we ever did a job that was over $1000. Costs of running the fans were pennies a month, and Fantech still sells the classic FR-100 fan all these years later, though there are even quieter options now.
There's typically enough gravel under the slab and around the foundation that there's plenty of soil-gas transport without doing anything more. So the install is just a simple vertical hole through the corner of the slab somewhere. Maybe you scoop out a few handfuls of soil before sticking the pipe in the hole, but there's no horizontal boring. Here's a very typical one:
https://www.flickr.com/photos/34878756@N04/9350845974
Here's another, including a side tap to a crawlspace:
https://science.gc.ca/site/science/en/blogs/science-health/e...
Not shown is the crawlspace portion of that system, which would use a horizontal perforated pipe _laying on the surface of the crawlspace floor_ and covered with a plastic membrane that's taped to the walls:
https://www.nachi.org/gallery/radon/crawlspace-radon-system-...
At no time is pipe tunneled horizontally under the house.
They didn't had diggers and drills in the 80's ?
Using modern tunnel boring equipment, Seattle's attempt to move the downtown section of 99 into a tunnel ended up stalled for a year because the ground shifted and pinched the boring machine in place. Oopsie.
And of course if you're worried about gasses, puncturing a solid piece of concrete is just going to make that problem worse.
> Radon-resistant new construction (RRNC) typically costs a builder between $250 and $750. RRNC could cost less than $250 if the builder already uses some of the same techniques for moisture control.
https://www.epa.gov/radon/radon-resistant-new-construction-h...
Tricky bit I think is when you live in a state with small pockets of radon instead of broad regions. Then you're back into crapshoot territory.
Newly built houses are required to be radon-proofed, AFAIK.
Has the debunking itself been debunked? It's hard to keep track.
[0] https://www.osel.cz/3436-radon-neskodi-a-mozna-i-prospiva.ht...
Here is a map! [https://www.epa.gov/sites/default/files/2018-12/documents/ra...]
You can get the GMC-300E a bit cheaper, but with no temperature compensation sensor[1] it won't be quite as accurate.
[0] https://old.reddit.com/r/codyslab/comments/hk3jru/more_fun_w...
[1] https://www.gqelectronicsllc.com/support/GMC_Selection_Guide...
I wouldn't recommend it again, but if you received one as a gift, with a bit of tweaking, you'll be measuring random stuff in your house.
The cheaper single tube dosimeters will max out and saturate at radiation levels far below those that are immediately harmful to human health. (This was the source of the famous "3.6 roentgen per hour, not great, not terrible" meme-- he was looking at a meter that was reading off-scale high at 0.001 R/s)
If you're buying a dosimeter with the threat in nuclear war in mind, check the specs for maximum readings.
Quote from HBO's Chernobyl, the dramatisization of Anatoly Dyatlov: https://knowyourmeme.com/memes/anatoly-dyatlov
A more balanced view of him: https://www.rbth.com/history/330525-anatoly-dyatlov-chernoby... and https://www.history.com/news/chernobyl-nuclear-disaster-7-pe...
Aside: all of us, even the most competent engineers, can deny what is happening or make bad calls during an emergency, especially where everything is unknown during the initial stages. It takes very good training to teach us to make better emergency decisions - e.g. firefighter's training, and some military. Beware of selection bias in repeated deadly situations.
1. https://ludlums.com/products/all-products/product/model-3
2. https://ludlums.com/products/all-products/product/model-44-9
3. https://ludlums.com/products/all-products/product/model-44-1...
/s
It contains high quantities of radium which decays into radon, this should end well.
> "Phosphogypsum contains appreciable quantities of uranium and its decay products, such as radium-226," according to the EPA. And because the fertilizer production process concentrates waste material, "phosphogypsum is more radioactive than the original phosphate rock," the agency notes.
> "The radium is of particular concern because it decays to form radon, a cancer-causing, radioactive gas," the EPA adds.
https://www.npr.org/2023/05/09/1174789570/florida-roads-radi...
That's the thing about the uranium decay series. Just after radium, it has this gaseous stage called radon, which doesn't matter one whit when it's sealed into a rock; an atom of radon in the middle of a piece of granite just sits there for a few days and then goes right on into being lead.
But if it's near the surface of a grain of sand or something, that radium turns into radon and the radon escapes into the surrounding air. And it goes wherever the air goes for the next day or two, before turning into lead.
So if that radon is in the runoff, it just fizzes out like any other dissolved gas, and blows around in the air along with all the other gases that make up the air, exactly like any other radon that had an escape route when it was created. There's radon in the air everywhere, right now, a brief stop on the decay chain that is otherwise all solids. And those atoms of radon are undergoing alpha decay all the time, turning into atoms of lead, minuscule bits of dust popping into existence, everywhere.
Well, no more than any other heavier-than-air gas, like say, fog.
Radon forms very slowly.
Now we have states trying to override federal regulations because superpac donations.
I knew people who took this to an extreme by putting a high-voltage static charge on a needle, then placing the charged needle in a closed bell jar with a pile of thorium-doped lantern mantles. The tip of the needle would pick up enough radon daughters that it made a great rechargeable point source for cloud chamber demonstrations.
> Polarized or polarizable objects are attracted to strong electric fields
Polarizable objects align in an E field, they aren't attracted to the E field. I don't doubt you could contrive a field to move a polarized object, but the wording seems to be confusing an ionized object with a polarized object.