[Phys-L] Re: Radon (was Survey Meters)

[anngeorg at PACBELL.NET (Bernard Cleyet)]

Since radon liquefies just above subliming CO2, could one collect it
(along w/ water unfortunately) by using a dry ice-alcohol powered heat
exchanger?  The water problem could be solved by collecting from an air
stream following a refrigerator type dehumidifier?  One could monitor
the activity as its collected.


To prevent the need for cleaning I placed a filter (the viscose? used to
fill pillows) in front of our second floor bath window exhaust fan.  The
humid air assisted in the collection of mucho dust.  I found it quite
active even after some time (days). Is my memory bad?  I thought to
pursue it further w/ students from the Physics classes at N. Salinas
High, but no one was interested.  I'm not the only one very disappointed.

bc, who thinks, as suggested by ME's experience, the high level of Rn
may be from the hot shower water *.  We also have a bottom floor bath
window exhaust fan; this cries for a comparison.

The Salinas river is an underground one all our water is from wells.

Edmiston, Mike wrote:

> John Mallinckrodt said, "My guess is that the meter is recording the
> rate of beta decay from an initially stable population of Po-218 created
> by the alpha decay of Rn-222 in the air.   When the replenishing Radon
> source is removed, the Po-218 quickly (3 minute half life) alpha decays
> to Pb-214."
>
> This is close, but not exactly correct.
>
> If the 222-Rn level would stay constant in a room, then an equilibrium
> would establish and eventually all the daughters would be present at the
> same level.  It is not that one decays building up the next, and then
> that decays and builds up the next, etc.
>
> For example, suppose the 222-Rn level in the room would be 20 picocuries
> per liter of air (20 pCi/L), and this level is maintained, despite the
> cut