Re: Caveman NORM doses

[a.zapantis@qut.edu.au (Alex Zapantis)]

>The long U-238 and Th-232 half-lives limit the equilibrium rates of their
>respective decay products.  

Isn't the ingrowth of daughter products a function of the daughter half life
not the parent (for secular equilibrium)? At least the first few daughters
of the natural series have half lives much shorter than U-238 or Th-232 so
wouldn't one expect that those would be in equilibrium with the parent is a
very short time (geologically speaking)?

In the Th-232 series, ALL daughters have half lives much shorter than the
parent.

Regards



                        Alex Zapantis
                        Radiation Safety Officer                               
                        Queensland University of Technology          
                        Health & Safety Section                             
                        Locked Bag No.2
                        Red Hill Qld 4059
                        AUSTRALIA

                        Ph     : 61 7 864 3566
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                        email  : a.zapantis@qut.edu.au