Radon detector for under $100.00

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Richard Hull
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Radon detector for under $100.00

Post by Richard Hull » Mon Jan 30, 2006 3:31 pm

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 » Mon Jan 30, 2006 11:55 pm

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 » Tue Jan 31, 2006 12:45 am

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 » Tue Jan 31, 2006 4:02 pm

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

richnormand
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Re: Radon detector for under $100.00

Post by richnormand » Wed Feb 01, 2006 12:38 am

They are shiiping "my" unit tomorow.

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Re: Radon detector for under $100.00

Post by ChrisSmolinski » Fri Feb 17, 2006 3:41 pm

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 » Fri Feb 17, 2006 5:08 pm

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Re: Radon detector for under $100.00

Post by ChrisSmolinski » Fri Feb 17, 2006 7:25 pm

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 » Fri Feb 17, 2006 8:06 pm

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

richnormand
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Re: Radon detector for under $100.00

Post by richnormand » Sat Feb 18, 2006 5:30 pm

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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