Re: Sr-90 analysis QA

[Holloway3@aol.com]

Having had some experience with Sr-90 and Y-90, here is my opinion:

   1. Minimum chemical yield for Sr-90 , about 30%)

   2. Minimum chemical yield for Y-90, about 60%, simply because the yields
for Y-90        are likely to be much better and there is little reason for
loss compared to Sr-90.

   3. Y-90 ingrowth time- at least 10 days

   4. Y-90 decay time before counting - not more than one half-life (64
hours, I think)


Quite often there are QA requirements that require greater chemical yield
than 30% but 
I think these requirements are needlessly burdensome to the analytical
laboratories, and that is especially true of alpha counting, although in this
case, it is not alpha counting. 

                                                              R. Holloway







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