pedresel on tue 22 aug 00
Lanthanum-138 has a half life of 1.05E11 years (a) and makes up 0.09%
(atom %) of natural La
Neodynium-144 has a half life of 2.38E15 a and has an abundance of 23.8%
Samarium-147 has a half life of 1.06E11 a and has an abundance of 15%
Samarium-148 has a half life of 7E15 a and an abundance of 11.3%
Gadolinium-152 has a half life of 1.1E14 a and an abundance of 0.20%
Lutetium-176 has a half life of 3.78E10 a and an abundance of 2.59%
By comparison, the half life of uranium-238 is 4.47E9 a and an abundance
of 99.2745%
and potassium-40 has a half life of 1.27E9 a and an abundance of 0.0117%
The longer the half life, the fewer decays per second for any given
number of atoms. The lower the abundance the fewer atoms of that
isotope per amount of the element and thus the fewer decays per second.
I wouldn't dare tell you what to do but I have worked with lutetium and
gadolinium sulfides in laboratory experiments using no more than
standard laboratory precautions (of course I was an expendable graduate
student back then). The sulfides are interesting. They are transparent
to infra red which can be very useful.
Hope this helps.
-- Evan in W. Richland WA where the geese have been flying around in Vs
but I think they are just practicing.
iandol wrote:
>
> Dear John B. Paine III,
>
> Would you please confirm that there are no Radioactive isotopes in naturally occurring Lanthanide elements or their compounds. I have read that some of these these substances must be handled with special care because they are emitters.
>
> I also understand that Chinese parties have already patented lanthanide use in the production of fluorescent glazes.
>
> Can you provide enlightenment on these questions.
>
> Ivor Lewis.
>
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