Re: I-125

["Deborah P. Steva" <dps3c@watt.seas.virginia.edu>]

> use I129, as a calibration standard to simulate I125, you're underestimating
> your efficiency by nearly a factor of two. Plus, I125 has a sum peak circa 60
> keV, which can further enhance your efficiency, if your counting window is
> set wide enough to include it.
> You could contact Isotope Products Laboratories for info about the sort of
> standard(s) you need: (818)843-7000. I suggest that you ask for the full
> catalog, which has lots of glossy photos, which make it easier to think about
> what you need/can afford.
> 
This is true, but it is expensive and a pain to have to
continually by a new I-125 source.  The other option is to buy
an I-125 source and I-129 source, count when activities are
identical and estblish a correction factor that can be used
when you count the I-129 standard in the future.

D. Steva