Is it possible to identify such an isotope? What are my choices if I wanted such a long half-life product. (Ultimately, I need it to activate a timing switch....!) :D

Thanks, anyone for any pointers.

AA

Try Wikipedia. They might have a list somewhere.

Here is a neat little search tool for isotopes ( http://www-nds.iaea.org/nudat2/index.jsp ). You can specify a half life and do a search for isotopes by clicking on the "Decay Radiation Search".

-Dale

There is an isotope of uranium with a half life as long as the earth itself.

I think it is U-235 or U-238 that has a half life of 4.52x10^9 years.

Arc