Re: Glow in the Dark Watches

["Dale E. Boyce" <dale@radpro.uchicago.edu>]

I would expect that the major activity is Pm-147.  It is a weak
beta and very low gamma branches, but can be measures on very
well shielded Ge systems. (The one I used was in a subbasement
with a two meter concrete ceiling, over 10,000 pounds of lead
surrounding a 4" thick pre-war steel cave)

Rare earth elements are not easily separated from each other,
so I suspect that the Eu is a trace contaminant.

Dale Boyce
dale@radpro.uchicago.edu