Re: I-129 Sources

[Wes Van Pelt <WesVanPelt@att.net>]

>
>
> >I believe what you are referring to is commonly called "a mock iodine"
> >source.  The I-129 is configured in such a way that the emitted spectrum
> >mimics that of I-125 but has the obvious advantage of the extended half
> life
> >of I-129.  Most gamma counter equipment vendors would be happy to link you
> >up with direct vendors or may even be able to provide such sources
> >themselves.
>
> "Mock Iodine" is not I-129, it cannot be, because I-129 is not a
> gamma-emitter. Somewhere deeply buried in my brain the information is
> stored, maybe it was Ba-133. Daren is right - the vendors can answer this
> questions.
>
> Franz
>

Franz and all,
I-129 has a very abundant (about 0.8 ?) x-ray at about 31 keV which is very
close in energy to the xrays and gamma ray of I-125.
It is true that I-129 is sometimes called "mock I-125" because their photon
spectra are almost identical. If fact, "mock I-125" can better be made with
both I-129 and Am-241 because the 60 keV gamma photon from Am-241 minmics the
60 keV co-incidence peak you see when I-125 is counted in a well-type counter
or with "good geometry".

btw, Ba-133 is "mock I-131".

Wes
--
Wesley R. Van Pelt, Ph.D. CIH, CHP
Wesley R. Van Pelt Associates, Inc.
Radiation Safety and Environmental Radioactivity
mailto:wesvanpelt@att.net


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