Re: Th-232 air sample analysis

[LEHaskell@aol.com]

We've been using a fast & dirty gross alpha screening to monitor a thorium 
clean-up site.  Several years ago we simulated windblown contamination using 
a bucket of contaminated soil and a vacuum blowing.  We analyzed the filters 
using both gross alpha and alpha spec to establish a correlation curve.  We 
conservatively estimate that 20% of the alpha activity is from Th-232.  
Periodically we take some of our air samples to check this assumption and it 
has worked well.  We monitor 13 locations with weekly samples.

Larry Haskell
Illinois Dept. of Nuclear Safety
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