Re: Unknown Sealed Sources

[avest@magnus.acs.ohio-state.edu (Albert Lee Vest)]

Michale Cappas writes,

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

It's short for "Radium D and Radium E."  In the old days, the daughter
nuclides in the Ra-226 decay chain were assigned letters.  The lettered
progeny were later chemically identified.  Ra-D turns out to be Pb-210,
while Ra-E is Bi-210.  By now, these are surely in equilibrium with Ra-F,
too, also known as Po-210.

>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).

Assumption is wrong.  See above.

This pair of half-disks is usually sold with a matching white plastic
*blank* half-disk.  The set is a tool useful in determining resolving time
of flat-wipe or planchet counters, such as GM or gas-proportional counters.
More details available on request.

Albert.

Albert Lee Vest           The Ohio State University
Health Physicist    Room 103 1314 Kinnear Road Bldg
(614)292-1284                     1314 Kinnear Road
avest@magnus.acs.ohio-state.edu   Columbus OH 43212
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