[ RadSafe ] Alpha to Beta Ratio Source Indication

Earley, Jack N Jack_N_Earley at RL.gov
Tue May 29 09:35:15 CDT 2007

During an assessment I did there in about 1993, I recommended that the
site use the combined half-life for radon daughter products of 33
minutes; they were using an in-house position paper for reference that
had a different number that was incorrect. And I believe you can find
that 33-minute reference in Gollnick.

You also have an alpha spec there that was working correctly after I
re-wrote the procedure for it about six months after the assessment.
Your best bet short of the alpha spec is to let your samples decay for
half an hour after initially counting them if they read high for alpha;
if they're still high, let them decay 24-72 hours (different sites use
different numbers--compare decay results w/ your alpha spec results to
find your best fit).

Jack Earley
Health Physicist

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