RE: Critics Allege Infant Mortality Rate

["LANNI, MARC" <MLANNI@entergy.com>]

	Bob,

   Maybe I missed something earlier, but where would the mis-identification
of K-40 with Sr-90 occur. I was under the impression that the K-40 has
a very active gamma (about 1460 KeV) however, the Sr-90 is no where close.
Even if you were to measure the Y-90 counterpart the energies are so far
off, I don't
know that you could really confuse the two? If Im off base here let me know.

       Marc

> Marc Lanni  <mailto: mlanni@entergy.com>
> Grand Gulf Nuclear Station - Health Physicist
> Entergy Operations
> mlanni@entergy.com
> Office:	(601) 437-6572
> Fax:         (601) 437-6573 
> Pager:	(601) 930-8904
> 


-----Original Message-----
From: Bob Flood [mailto:bflood@SLAC.Stanford.EDU]
Sent: Thursday, April 27, 2000 12:55 PM
To: Multiple recipients of list
Subject: Re: Critics Allege Infant Mortality Rate


>Potassium, an alkali metal chemically similar to sodium, does not behave in
>the same manner as the alkali earths and would not be expected to reside in
>bones to the extent Calcium and Strontium would.

Ok, this is turning out to be an educational experience for me (and a
demonstration of why I think of myself as a physicist and not a chemist).

However, your use of the phrase "to the extent" leaves me with the same
question. If potassium is present in baby teeth, then K-40 is also present,
and that presents an opportunity for the analytical technique to misidentify
it and call it Sr-90. I assume that the tooth material would be pulverized
and then subject to some extraction process to obtain the strontium in a
solution that would be subject to liquid scint counting. Would a commonly
used strontium extraction technique also capture potassium? If so, how would
one account for K-40 in the analysis? Gamma spec analysis seems the logical
approach to me, but I've already shown my lack of expertise in this area.

Perhaps more to the point, can anyone estimate how much Sr-90 one would
"think" is found if only K-40 is present but not accounted for?
============================
Bob Flood
Dosimetry Group Leader
Stanford Linear Accelerator Center
bflood@slac.stanford.edu


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