Practical demonstration of a half-life

[Brian Rees <brees@lanl.gov>]

With a vacuum cleaner and an air filter (even tissue/toilet paper) you can
capture enough radon progeny to not only show half-life, but natural
background, counting limitations, etc.  
Just beware: depending on atmospherics, you'll collect different amounts on
different days, and at different times (so don't over-plan your expected
levels).  With an effective half-life of about 1/2 hour you can show it
decaying with good statistical strength (collect lots and start counts
soon) or decay to (basically) nothing if you collect small amount.  With a
b/g instrument you can show the difficulty of low count rates and
background subtraction.   

Have fun,
Brian Rees
brees@lanl.gov
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