Absorption Factors

["Mitch Davis" <mdavis@normdecon.com>]

Good Afternoon:

We are going to begin counting our own air samples generated at our decon
facility using a low background proportional counter.  In the standard
activity calculation, the denominator contains the self-absorption factor
(SA) which, as we all know, corrects for alpha absorption in the filter
media.  I have determined the SA for our filter media.  It has been sometime
since I have delt with this and I think some "flushing" of my memory has
occurred.  Therefore, I am requesting some assistance.  If the SA has been
determined to be, let's say 40%, should we use the decimal equivalent of
that (i.e. 0.4) in the activity calculation or rather 0.6 which would be the
actual % of alphas not absorbed (i.e. counted) by the detector?  It is my
recollection from the past that the 0.4 would be the proper number to use.
Any thoughts?  You may respond directly to me at the below address.  Thank
you all.

Mitchell Davis, RRPT
RSO, NORM Decon Services, LLC
Midland, TX
915-563-1123
mdavis@normdecon.com


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