Re: Leak Testing Radium Sources

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

Another thing to consider:  Are you looking at a radon or radium leak?
How long has it been leaking (the Ra(D) has a long half life and grows
in slowly)?  If it is a recent radon leak the sample may have decayed
between the time you measured with the proportional counter and the
time you made the gamma count.  Most radium source leaks are just radon
leaks.  As has been pointed out elsewhere the gamma count gives you
the activity of the parent where the proportional count will give the sum 
of the activities in the chain that are present, or at least a fraction of
the sum.

Dale
dale@radpro.uchicago.edu