Radon dosimeters...

[Externet]

Radon dosimeters work by 'sniffing' the air or by measuring its signature radiation ?

[John Cuthber]

What do you mean by "sniffing"?

 

[swansont]

Which kind of dosimeter were you asking about?

[Externet]

Here is a few.  Perhaps each works on different principles

----> http://sarad-radonshop.com/doseman-radon-exposimeter-dosimeter?language=en

----> https://www.cphklima.dk/produkt/kodalpha-dosimeter-radonmaaling-sporfilmsmetoden/

----> http://www.englo.eu/en/products/toode/radiation-measuring-devices/radiation-mesuring-device-radon-3-3/

By coincidence, the 'sniffing' word I used is also at this site ----> http://www.mearec.ch/radon-messung.php

[John Cuthber]

4 hours ago, John Cuthber said:

What do you mean by "sniffing"?

 

 

[swansont]

1 hour ago, Externet said:

Here is a few.  Perhaps each works on different principles

----> http://sarad-radonshop.com/doseman-radon-exposimeter-dosimeter?language=en

----> https://www.cphklima.dk/produkt/kodalpha-dosimeter-radonmaaling-sporfilmsmetoden/

----> http://www.englo.eu/en/products/toode/radiation-measuring-devices/radiation-mesuring-device-radon-3-3/

By coincidence, the 'sniffing' word I used is also at this site ----> http://www.mearec.ch/radon-messung.php

First one is "Diffusion, HV chamber, semiconductor detector, alpha -spectroscopy"

Radon diffuses in, there's a HV chamber with a semiconductor detector of (I assume) some ionization current spike.

second one analyzes exposure of photographic film, or something similar. 

Third one flat out says it's a Geiger counter.

Last one says sniffing but the rest is in German (like the second) so that's not much help

 

 

[Bender]

17 minutes ago, swansont said:

Last one says sniffing but the rest is in German (like the second) so that's not much help

My German isn't great either, but I guess there is a scintillator inside:

Quote

Scintillationsmesszelle

 

[Externet]

Hi John :

'Sniffing' meant as a method  mechanically passing  air trough a discerning physical/chemical/spectral/... sensor chamber/duct that could detect radon regardless of its radioactive emissions , in opposition of sensing only presence of radioactive emission alone and assuming comes from radon, with no air/gas flow into a sensing chamber.

This one shows "unaffected by other radiation" ----> https://airthings.com/wp-content/uploads/2017/12/Home_product_sheet_US.pdf

The metering reports radioactivity as pico Curies per litre, perhaps some show as Bq/m3; not parts per million concentration in air.

Edited April 29, 2018 by Externet
Added link

[Externet]

In different units.  Showing the exposure to its radiation, but not the amount in air (correlates?)

[Bender]

Some rulers are in inch, others in mm. Bq is the SI unit and defined as 1 decay/s. Ci is an older unit based on the activity of 1g of radium and corresponds to 37 billion decays/s or 37 billion Bq.

I would be surprised if these dosimeters don't have a setting to display one or the other.   

[swansont]

11 hours ago, Externet said:

Hi John :

'Sniffing' meant as a method  mechanically passing  air trough a discerning physical/chemical/spectral/... sensor chamber/duct that could detect radon regardless of its radioactive emissions , in opposition of sensing only presence of radioactive emission alone and assuming comes from radon, with no air/gas flow into a sensing chamber.

No, I don't think you are detecting it regardless of its radioactive emission. That would imply some chemical or spectroscopic detection.

https://durridge.com/products/rad7-radon-detector/

"The RAD7 is a Sniffer that detects the 3-minute alpha decay of a radon daughter"

http://radonsniffer.com/CT007R_Operation.htm

"Air is continually pumped through a scintillation cell and the radon concentration in the air is calculated every 3 seconds."

I get the impression that a sniffer takes air into the device and does the detection, while other detectors simply detect alphas that hit a detection window. But it's all radiation detection.

 

11 hours ago, Externet said:

This one shows "unaffected by other radiation" ----> https://airthings.com/wp-content/uploads/2017/12/Home_product_sheet_US.pdf

beta and gamma will have different signal signatures, so I imagine they are filtered out.

11 hours ago, Externet said:

The metering reports radioactivity as pico Curies per litre, perhaps some show as Bq/m3; not parts per million concentration in air.

You should be able to convert, since we know the half-life. A = LN

A is the activity, L is the decay constant (often lambda) and N is the number of atoms.

[John Cuthber]

16 hours ago, Externet said:

The metering reports radioactivity as pico Curies per litre, perhaps some show as Bq/m3; not parts per million concentration in air.

I'm not surprised.

Given this data

https://www.atsdr.cdc.gov/toxprofiles/tp145-c4.pdf

A picocurie of 222Rn is about 1.6E-17 grams 

So a pCi per litre is something like a millionth of a part per million (or thereabouts- I lost count of the zeroes).

It's not being detected by chemistry at that level (not least, because it's inert).

 

There are radon monitors that have pumps to draw in (which could be viewed as "sniffing") and there are detectors which rely on diffusion.

 

[Externet]

Thanks, gentlemen.

I take then that radon dosimeters are not radon gas dosimeters but dosimeters for radiation from radon decay.

[swansont]

8 hours ago, Externet said:

Thanks, gentlemen.

I take then that radon dosimeters are not radon gas dosimeters but dosimeters for radiation from radon decay.

A dosimeter measures a dose (or dose rate) of ionizing radiation. "dosimeters for radiation" is redundant.

[John Cuthber]

8 hours ago, swansont said:

A dosimeter measures a dose (or dose rate) of ionizing radiation. "dosimeters for radiation" is redundant.

Unless it doesn't.

https://en.wikipedia.org/wiki/Noise_dosimeter