Radon Emission in Granite

[s.taba]

I am trying to measure the amount of radon released from different types/samples of granite.
Where do I get a good radon detector and what will I have to pay?

[barretttomlinson]

Hi,

Would it not be more fun to build your own radon detector? Why don’t you look into building a Wilson cloud chamber? It will detect alpha rays(as well as other charged particles), and radon is an alpha emitter. Here are articles on how to build one:

http://www.lns.cornell.edu/~adf4/cloud.html

http://www.masc.ulg.ac.be/fiches/EN/wil ... hamber.pdf

http://hyperphysics.phy-astr.gsu.edu/hb ... cloud.html

Here are youtube videos of cloud chambers in operation:
http://www.youtube.com/watch?v=kuzWNOUq ... re=related

http://www.youtube.com/watch?v=VTchJOOa ... re=related

http://www.youtube.com/watch?v=chxv5G6UFl0&NR=1

I think you might be able to get a feel for the relative radioactivity of various types of granite with this device. If you want to find a real radon detector try a search for radon detector using google. You should be able to find what you want that way.

Best wishes for a great project!

Barrett Tomlinson

[acgoldis]

Hi!

I'm probably not an expert on this, but using a cloud chamber to figure out radon emissions could be a bit tricky. Wouldn't it pick up other radioactive nuclei as well? Generally, where there's radon, there's radium, and the signal from radium could dwarf the signal from the radon. What's more, I wouldn't be surprised if there are some thorium and uranium ores running around in there as well (where'd the radium come from?), and some of those daughter products could also be radioactive.

If you just want to go after radon, there could be a rather sneaky way to go about it (you may have to fine-tune this though).

1. Take your sample (with the usual safety precautions) and put it in an indentation in the bottom of a sealed box. This box is connected to another box by a pipe. Put the boxes in a vacuum.
2. Put some substances which will react with any released fluorine and oxygen in the indentation as well which will produce solids. This will get the O and F out of the way so they can't react with any radon. You may want some stuff which picks up hydrogen as well.
3. Geiger counter the second box for a baseline.
4. Wait a while.
5. Slide something over the indentation so no solid contaminants can screw up step 6.
6. Pipe all of the gas in the first box into the second box.
7. Geiger counter the second box again. It went up. Obviously, somebody stuck a radioactive gas in the second box.
8. How much did it go up by?

Here's another variation, possibly even simpler. Again, I haven't thought this through yet.

1. Stick your sample on top of a platform in a sealed box filled with argon or xenon (or even air). The sample is in an indentation so no pieces or crumbs can fall to the bottom.
2. Geiger counter the bottom of the box for a baseline.
3. Wait a while.
4. Geiger counter the bottom of the box again. Did it go up? If it did, a radioactive gas denser than Ar/Xe/air came out of nowhere.

ACG

[mfeit]

S. Taba,

If your purpose is measuring the radioactivity from radon, making a cloud chamber as B. Tomlinson suggested would be an interesting and fairly easy way to detect radiation. You could provide for acgoldis' concern by comparing the activity both near and far away from the supposed radon source. That is, take a look at naturally occuring radiation due to cosmic rays, etc and consider that as a base level. Good luck on your project.