Re: Radon class demo

["Philippe Duport" <pduport@synapse.net>]

Joe,

Short-lived radon decay products have, collectively, a half-life of about
35 - 40  minutes and, for all practical purposes, all beta-gamma emissions
come from Bi-214 alone.  You need to sample for about one half-life (say 40
minutes) to reach the maximum activity you will ever get on a filter at that
location.  In two minutes, you probably do not collect enough radon deacy
products to obtain a reading with a GM tube.  One suggestion: monitor the
activity  the filter while sampling, until you obtain a reading.  If you
still have no counting after 20 or 30 minutes, give up, there is little
chance you will count something for the combination of radon progeny in air,
your sampling train and your monitor.

Philippe Duport
University of Ottawa


Original Message -----
From: Joe Provost <provost@mhd1.moorhead.msus.edu>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Sent: Monday, September 27, 1999 1:09 PM
Subject: Radon class demo


> Last year a string went out about demonstrations of half life.
>
> One very interesting idea was to use a vacuum cleaner and an air filter
> (even tissue/toilet paper) to  capture enough radon progeny to not only
> show half-life, but natural
> background, counting limitations, etc
>
> I tried this using thick filter paper and after 2 min of filtering I did
> not detect any activity over background with a GM counter.
>
> Any ideas?  I am in the upper midwest and this area should have a pretty
> high conc of radon gas.
>
>
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