Re: Self-shielding in air particulate samples

[Wes Van Pelt <vanpeltw@idt.net>]

Hi All,
I also was looking recently for a technique for correcting for
self-absorption in a filter paper. I remember an experiment we did in a lab
course at NYU where we alpha (beta?) counted both sides of a paper filter
and caclulated the total activity based on the cpm on each side.  My memory
says it was a radon daughter air sample pulled on an 8x10-inch paper
filter.  But I could not derive the formula, or remember exactly how it was
done.  Anyone else have Ed Wrenn's course on radiation counting
instrumentation?
Regards,
Wes
--
Wesley R. Van Pelt, Ph.D., CIH, CHP            KF2LG
President, Van Pelt Associates
Radiation Safety and Environmental Radioactivity
mailto:vanpeltw@idt.net    http://idt.net/~vanpeltw/


Joel Cehn wrote:

> Heavily loaded air filters will exhibit self-shielding, when counted for
> alpha, or soft betas.  What techniques are used to correct for this?
> The commercial labs that I have contacted usually don't correct for it,
> since they are only looking for "gross counts."  Has anyone seen a
> theoretical treatment of this correction?
>
> Joel I. Cehn, CHP
> JCehn@att.net
>
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