Radon detector for under $100.00

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Radon detector for under $100.00

Post by Richard Hull »

Some of you may already have seen these somewhere, but I just purchased from.....

http://www.radonease.com/

.....a really slick little radon detector. As most of you know, I have a small collection of U ore minerals in my mineral collection. I was concerned about accumulating radon in my upstairs lab as some of my specimens that are in the open are quite hot. As we all know, radon oozes out of U rock at a rather constant rate over a period of billions of years.

As many of you also know, I have an $8000.00 Pylon radon test kit with three lucas cells and all the electronics to test radon levels to a high level of precision. The kit requires about 1 hour to set up and take a sample. It also requires a 20 hour sampling period with a new scintillator reading automatically taken and recorded every 10 minutes from the lucus cell with the trapped air sample in it. All this is recorded on a printer and after 20 hours, averages are taken and equations solved, manually, to determine the actual room level in pCi/liter. All of this warrants a very high degree of precision with very little error.

This swift little detector that I just purchased uses a special internal ion chamber and, after 7 days of total stupidity, it finally throws up your room's radon level to within +/-20% in pCi/liter on a nice, continuously lit, 3 digit LED display. After two weeks, I am most pleased with its performance. Once it finally does readout, (~3-7 days of sampling) it will do a continous daily update to your continuous average level in "long term" mode.

I have mine set to "short term" mode and once it starts to read, the average is updated hourly until the seventh day when it erases all past data but keeps the current reading and starts another hourly updated seven day cycle.

This thing has a micorprocessor in it with several modes and features plus, a small manual comes with it. Woe betide the idiot who unplugs it as it starts all over again on the 3-7 day dummy cycle reading two dashes "--". You will want this on an unswitched outlet where kids and other family dunderheads will not disturb it. You can forget instant gratification with this thing. It comes with the customary "wall wart" and a generous 10 feet of wire on it for locating it anywhere.

If you are looking at a living space with constant comings and goings the long term mode is best. If you are looking at a non-living area where there is little traffic you might want to use the short term mode as it picks up short term increases better.

The readout is rounded to the nearest whole digit, BACKWARDS!

1.1 or 1.9pCi/liter is readout as "1" There are no decimals, obviously, in a $100.00 instrument of this type. It sounds an alarm of four loud beeps every hour if you are over the government acceptable, continuous living limit of 4 pCi/liter.

My unit, after two weeks, reads "1", so, I am most happy.

I spent the time over the weekend and arrived at 1.73pCi/l with my professional setup and so the little box is doing OK and so is my lab space.

I attach an image of the device in my upstairs lab. I have it on a wall near my minerals. Pretty cool for a bit of piece of mind.

Good news for all you folks with 159pCi/l basements. You can breathe a radioactive sigh of relief..... The alarm on this puppy can be turned off in the menu mode!

Richard Hull
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Re: Radon detector for under $100.00

Post by richnormand »

Very neat device for the price.

Have you considered putting the unit in a sealed box with one of your ore samples and see if its radon indication will actually go up? If the ore radiation upset it a simple two box setup with a connecting tygon tube between the two might do it? Same with putting it in a sealed room and look for an increase?

Cheers and thanks for the info.
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Re: Radon detector for under $100.00

Post by richnormand »

OK too late!
Just purchased one unit and I'll run the experiment.
Fun fun fun...
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Re: Radon detector for under $100.00

Post by Richard Hull »

Remember, this ain't instant gratification it will take 20 days or so for any source to reach radon equilibrium and 7 or more days after that for the detector to have sniffed it out.

How much radon will be in the box will depend on the source activity and how much is surface related.

I have been thinking about how this thing works and it waits until it is effectively loaded with radon and daughters in equilibrium and has to divide the result by 2 or 3 as there are about 2-3 alpha daughters that will clog the ion chamber over the averaging period. It is all part of a complex equation that this thing is cal'd to from the start.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Radon detector for under $100.00

Post by richnormand »

They are shiiping "my" unit tomorow.
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Re: Radon detector for under $100.00

Post by ChrisSmolinski »

Richard,

Have you peeked inside this unit? Is it just an ionization chamber? Anything
unique about it?
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Re: Radon detector for under $100.00

Post by Richard Hull »

It is all microprocessor based. A small cpu runs the whole shootin' match; and, yes, it is an ionization chamber, but handled rather specially.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
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Re: Radon detector for under $100.00

Post by ChrisSmolinski »

Could you elaborate on how the ion chamber is handled specially? I'm
curious.
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Re: Radon detector for under $100.00

Post by Richard Hull »

I am obviously not privy to the specifics of how these folks programmed their CPU, but it doesn't that a huge leap forward in brain power to noodle out what is probably done.

The chamber, which is open to air circulation doesn't concern itself with radon at all, much as all radon detectors fail to look at radon directly. Instead, they look at daughter products. Slowly the daughter products from a given radon level accumulate to a stasis or equilibrium point.

It is to be remembered that for every radon atom that decays while in the chamber you have a whole gang o' alpha, beta and gamma emitters now locked in the chamber (they don't exit). Once you have a fixed chamber volume, it is a matter of a little empirical measurement with high grade instruments to establish all of the math and a lot of constants that make back-figuring radon levels over long intervals a snap! The cpu handles all of this mathematical sadness. Compared to keeping the LED display alive and comprehensible plus making the menu functions happen, the math figuring part is child's play. In addition, the whole rig only updates on the hour in fast mode and every 7 days in long term mode. Definitely not a Cray at work here.

The chamber collector is undoubtedly hooked to an FET or FET input op amp and very crude A to D conversion occurs based on ion current which is a function of the radiation levels in the chamber.

Remember radon is never measured when measuring radon levels.

Make no mistake, nothing replaces the pinpoint accuracy to a large volume lucas cell talking into a scintillator, feeding data to a full fledged computer. I would not feel happy trusting this little rig to more than +or- 0.5 pCi/l, which is actually quite good for the buck spent. The big thing is...... this little rig WILL let you know if the angel o' death is moving into your living space but only after he has been circulating in your lungs for about 7 days. ( a mere trifle, biologically)

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Radon detector for under $100.00

Post by richnormand »

I was tempted to open the housing on mine, but it is not possible without voiding the warranty seals in quite an apparent way. So I’ll wait a few months and make sure it’s working OK before exploring the insides.

It has been two weeks of readings in the basement. It started indicating after three days or so with a reading of 0 and has now settled on 1. Too bad there are no decimals to follow its progress.

After a while I will put the unit in a sealed box with about ten radium watch dials and needles and see if it can pick up the radon building up in there. This would verify if it can read higher concentration with little air circulation. The specs say it can indicate 999uC/L, which would freak me way out.
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Re: Radon detector for under $100.00

Post by Hayabusa »

Question:

Can Radon be detected with a "Geiger-Mueller tube" ???

Thanks in advance
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Re: Radon detector for under $100.00

Post by Hayabusa »

I found this info.

Radon Progeny (decay chart)
http://www.ccnr.org/radon_chart.html

Geiger-Mueller Tube explained
http://www.warren-wilson.edu/~sleavitt/ ... ebpage.htm


Since a Gieger-Mueller Tube detects Alpha, Beta, and Gamma, therefore the Tube is capable of detecting Radon decay.

Is this correct?

T.I.A.
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Re: Radon detector for under $100.00

Post by Richard Hull »

Radon is a simple alpha emitter and can be detected with a thin, mica windowed GM tube.

Again, how are you going to know unless you have a significant radon level??

Background levels are NEVER stable ANYWHERE!

More or less, radon just will not be seen as part of the equation.

Collecting and concentrating the daughters is about the only method that will give a significant way of back figuring normal 1-6 pCi/l radon levels. This is why virtually all radon testing methods do this.

I have seen and measured intense radon levels with a GM, but these are astronimcal in nature and never seen in a living space. They are more likely encountered in old U mine shafts and the like. Even here though, "wall effect" will contribute to what a GM tube is seeing and counting so, once again, unless you have a draft out of a mine shaft you will not notice radon, per se, in a GM count. You will not be able to offer any quantitative information over the stock, qualitative, "holy sh--" or "it ain't too bad in there".

Radon being vastly heavier than air will collect in gravational pools in low lying, still air areas. If you can approach a depression slowly, you might see a doubling of background!

Placing a counter probe at the bottom of a 60 inch length of 6" diameter PVC pipe with several open old meter faces held at the very top will freak you out if you plot the radiation over 21 days.

The counter will never see the sources at the 5 foot distance, but once the radon starts falling from on high and the daughters start to settle out....... MAN!

NOTE** you will have fouled your GM tube with daughters for about 4 days or more once the experiment is over.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Radon detector for under $100.00

Post by DaveC »

I just checked the website for the Radon progeny. I think the decay diagram is correct, but the explanation seems confusing to me... "a Proton emitting an electron and becoming a neutron"?? I could see a neutron emitting an electron and becoming a proton.. but not the other way....

Need an expert to weigh in here...

Dave Cooper
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Re: Radon detector for under $100.00

Post by Richard Hull »

Dave is correct. Someone is whacked out.

Radon decays to polonium 218 via alpha decay.

The Po218 is a solid and not a gas, as are all the subsequent daughter products. Anyway, the Po218 decays with a half life of ~3minutes via alpha to Pb214 which decays by beta decay to Bi214. The Bismuth then decays via beta decay with a half life of about 20 minutes to Po214. The Po214 now decays by alpha emission with a half life of ~100usec to Pb210 where, for detection purposes of radon, the process stops as Pb210 takes ~100 years to reach equilibrium. We see that we have trapped 5 radioactives if one includes the radon. Three alpha emitters and and two beta emitters can reach total equilibrium within 15 days or so locked within the chamber. If one excludes radon and just looks at the valuable daughters which are solids that are "cast down" into the chamber, it only takes about 2 hours to reach equilibrium between the four useful daughters. All emissions are common Beta and Alpha particles. Beta emission is generally handled as the internal breakup of a neutron which bumps the atomic number up one due to a new proton while its electron zips on out of the nucleus as a beta particle.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Radon detector for under $100.00

Post by richnormand »

Got my series 2 detector three weeks ago. It works fine but.... just found out the series 3 is now out and it reads the decimals too..... Oh well....

See:

http://www.radonmonitor.com/

And it is at the same price....
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Re: Radon detector for under $100.00

Post by Jon Rosenstiel »

Just plunked down $100.00 for a series 3 unit. Stay tuned for a radon report from the left coast.

Jon Rosenstiel
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Re: Radon detector for under $100.00

Post by richnormand »

After two weeks in the basement my series 2 unit registered 0 for a few days after the initial setup time with --. It then moved to a steady reading of 1 for the next weeks.

Now five days ago, I put it in my closed sample boxe with various test sources. It went to 11 the first day and now indicates 56! So either it is miss-reading the "background" radiation as radon decay products or actual radon buildup in the closed box.

I just now restarted and reinitialised it next to the sources but out of the box and in free air. If I get the same behaviour as before it will be the radiation, if not, and the reading is lower, then it could be the actual accumulation of radon in the box.

It is possible the unit spends the first two days (with the -- reading) is to establish the background rad. In that case sitting at reset on the sources should nul out the high reading, I think. Next thing to try over the next weeks.

The final test will be to put a large and long tube with the sources at one end and the detectors away at the other. Something like 10 or 12 feet away with the tube sealed on each end. In that case only radon should cause a high reading with a rate slower by the increased volume compared to the sample box....

Comments, suggestions.? You are lucky as the series 3 has decimal readout so you can perform this experiment faster than I can.
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Re: Radon detector for under $100.00

Post by Richard Hull »

You can go to the bank with the fact that your samples in a small tight box WILL push the radon levels to very high values. Again, it is slow to respond as it is an intergrating ion chamber, but it will respond. You will need to be careful as some of the radon daughters near the end of the chain are quite long lived.

Radon will take at least 20 days to approach equilibrium every time the box is opened. You will not get and accurate max figure for probably a month.

The real test for radiation vs. radon detection would be a thick lead block separating your sources in the same closed box. The detector just needs to breathe the air and not be in a gamma field.

I will be most curious if your meter drops to your old background reading in a reasonable period. (might be slightly contaminated after being in the box with all the radon and the related daughters.)

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Radon detector for under $100.00

Post by Frank Sanns »

These detectors contain an alpha only detector. They should not pick up any gammas from an external source. Alpha only detectors can be incredibly selective. I have a 50 cm^2 surface area alpha only probe that will read 50,000 cpm/cm^2 with a hot ore sample a couple of mm away from it. Slide a piece of paper between the source and the probe and the counts drop to well under 50. Use a piece of cardboard or thick paper and the counts will be <1 per minute even in the strong gamma and beta field of the sample.

To prevent airborn alpha emitters that are not radon gas from adversely affecting the reading, there is typically a thin plastic chamber that encapsulates the detector. No particulates can get to the alpha only detector. It is ony the radon that slowly diffuses through the thin plastic that ever makes it through to the detector. The choice of plastic and the thickness are of course very important so that X% of the radon will not have decayed before making it into the chamber. Sounds complicated but it really is an elegant way to detect only radon with little or no interference from other sources.

Frank S.
Achiever's madness; when enough is still not enough. ---FS
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Re: Radon detector for under $100.00

Post by Richard Hull »

Will radon diffuse through plastic??? That is a massive atom, even if it is monatomic.

The alpha only probe that Frank talks about usually uses a thin plastic mylar aluminized membrane that the alphas can penetrate. On the inside of the probe handle is a 1" PMT staring down on the inside of this large area membrane which is covered with ZnS. These probes are extremely good at alpha detection. These probes, alone, usually cost nearly $1000.00 new

Of course, in a $100.00 radon detector this is not the case. As I have not observed the inards in great detail, I can't speak with absolute authority. However, I am relatively sure this is a simple air breather ion chamber looking at an FET input probe. It is the only scheme that is inline with the price.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Radon detector for under $100.00

Post by Frank Sanns »

A half dozen interuptions and phone calls and click to post rather than loose the thought ended up being incomplete. Yes I agree that the electronic radon detector uses an ion chamber/MOSFET electrometer setup for alpha only detection. It will not pickup gamma. Try and you will be surprised how selective this cheap unit is. I have one and found my house to be at the 40 pCi/l range on the worst of days. There were other periods where the readings were as low as 2. Apparently low pressure weather system and rain are being reported as elevating interior radon. I don't know that I observed ANY correlation with any particuar phenomenon but the radon levels did vary over some kind of range.

Yes, diffusion is possible through polymers. There are a few ways that radon will go through a polymer. It can effuse through an open pore polymer or open cell foam. The pores can be small enough to not let the finest particulate through but still pass radon. Polymers can either be very symetrical and pack well or they can be very unsymetrical and have large side chains or atoms that prevent close packing. The intersticies of a polymers can be fairly cavernous as atomic sizes go. Also, copolymers (consisting of 2 seperate polymers) can have one polymer disolved out after it is formed to give internal paths for gasses to follow. Other additives, especially carbon blacks, can be added that provide a path through the polymer. The carbon particles provide an interface void at the polymer interface and makes an open albeit small channel for gasses to pass. It is well known in the industry that if you want a good vapor barrier, you don't make it black and you don't have voids it in of any kind.

Frank S.
Achiever's madness; when enough is still not enough. ---FS
We have to stop looking at the world through our physical eyes. The universe is NOT what we see. It is the quantum world that is real. The rest is just an electron illusion. ---FS
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Re: Radon detector for under $100.00

Post by richnormand »

Here is an update.

After the reading done in my air tight sample box (see previous post):

I installed the detector again on top of the exact same sources, but in the open air instead of in a sealed box. After the initial startup calibration “ – “ reading it started at 3 then dropped back to 1 (normal reading where I live) in a matter of three days. So at first glance, it does look like the previous high reading was due to radon building up in the box and it also looks like the detector is immune to a fairly high background.

I will now reset and redo the startup cal away from the sources and then repeat this setup exactly. Any difference of behavior would then be due to that initial cal.
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Re: Radon detector for under $100.00

Post by dbitton »

I bought this one in e-bay for $100 plus delivery. After I installed it in a little room (cave) in the basement of an apartment block, it started to read 2.5 pCi/liter steady for one week, BUT, when I moved to another "cave" close by, it started to read 4.1 and now after 10 days it reads 4.7 pCi/liter . Should I panic?, I read most of the reports "againts" EPA recomendations and found them very particylary interesting and "iluminating".
We are already planning to install some kind of extraction or circulating fan/duct to reach that "cave", even if that area is not accesible for most of the resident, except when I need to store my "surpluss" equipmetn and tools.
regards from downunder
Daniel
Richard Hull wrote:
> Some of you may already have seen these somewhere, but I just purchased from.....
>
> http://www.radonease.com/
>
> .....a really slick little radon detector. As most of you know, I have a small collection of U ore minerals in my mineral collection. I was concerned about accumulating radon in my upstairs lab as some of my specimens that are in the open are quite hot. As we all know, radon oozes out of U rock at a rather constant rate over a period of billions of years.
>
> As many of you also know, I have an $8000.00 Pylon radon test kit with three lucas cells and all the electronics to test radon levels to a high level of precision. The kit requires about 1 hour to set up and take a sample. It also requires a 20 hour sampling period with a new scintillator reading automatically taken and recorded every 10 minutes from the lucus cell with the trapped air sample in it. All this is recorded on a printer and after 20 hours, averages are taken and equations solved, manually, to determine the actual room level in pCi/liter. All of this warrants a very high degree of precision with very little error.
>
> This swift little detector that I just purchased uses a special internal ion chamber and, after 7 days of total stupidity, it finally throws up your room's radon level to within +/-20% in pCi/liter on a nice, continuously lit, 3 digit LED display. After two weeks, I am most pleased with its performance. Once it finally does readout, (~3-7 days of sampling) it will do a continous daily update to your continuous average level in "long term" mode.
>
> I have mine set to "short term" mode and once it starts to read, the average is updated hourly until the seventh day when it erases all past data but keeps the current reading and starts another hourly updated seven day cycle.
>
> This thing has a micorprocessor in it with several modes and features plus, a small manual comes with it. Woe betide the idiot who unplugs it as it starts all over again on the 3-7 day dummy cycle reading two dashes "--". You will want this on an unswitched outlet where kids and other family dunderheads will not disturb it. You can forget instant gratification with this thing. It comes with the customary "wall wart" and a generous 10 feet of wire on it for locating it anywhere.
>
> If you are looking at a living space with constant comings and goings the long term mode is best. If you are looking at a non-living area where there is little traffic you might want to use the short term mode as it picks up short term increases better.
>
> The readout is rounded to the nearest whole digit, BACKWARDS!
>
> 1.1 or 1.9pCi/liter is readout as "1" There are no decimals, obviously, in a $100.00 instrument of this type. It sounds an alarm of four loud beeps every hour if you are over the government acceptable, continuous living limit of 4 pCi/liter.
>
> My unit, after two weeks, reads "1", so, I am most happy.
>
> I spent the time over the weekend and arrived at 1.73pCi/l with my professional setup and so the little box is doing OK and so is my lab space.
>
> I attach an image of the device in my upstairs lab. I have it on a wall near my minerals. Pretty cool for a bit of piece of mind.
>
> Good news for all you folks with 159pCi/l basements. You can breathe a radioactive sigh of relief..... The alarm on this puppy can be turned off in the menu mode!
>
> Richard Hull
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Re: Radon detector for under $100.00

Post by Richard Hull »

Radon at 4 pCi/L is not bad provided the "little cave" is isolated and you are not there for protracted periods. I would not worry about it.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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