Unknown Sealed Sources

["Cappas, Mike" <cappas@mdaw.mdc.com>]

We have two sealed sources that are labeled Ra-DE. Does anyone know what the DE
stands for.

Some background information:
They are part of a Beta Source Set sold by Don L. Collins & Assoc. of Glendale,
CA (1979). Both sources are red-colored, half-disks, which make a 1-inch disk
when placed side-by-side. They are not labeled with any activity (only Ra-DE),
but are definitely radioactive (Ra-226, I assume).

I tried contacting Don L. Collins & Assoc., but they do not seem to exist any
more.

Any help would be greatly appreciated. Thanks...

Michael Cappas
cappas@mdaw.mdc.com

McDonnell Douglas Aerospace
Space & Defense Systems
Huntington Beach, CA