Re: "Nuclear B" disk

[Dave Derenzo <dave@uic.edu>]

Dale (and Ralph),

The meters you are referring to are Nuclear Chicago Models 2612, 2650 and
possibly others. The sources, which were medium grey in color, definitely
contain Ra-226 and came with the meters. I think the activity was under 1
microcurie but I could be mistaken.  We have a 2612 and a 2650 in our
collection (sources disposed of long ago). The 2612 has a source hloder on
the back end of the meter case and the 2650 has a source compartment in the
triangular shaped rear end of the instrument. Both suggests a size of 1
inch in diameter and a thickness of about 1/2 inch or slightly less. As I
remember, one side was marked "Nuclear A" and the other "Nuclear B" so that
the source could be used to obtain two different check source readings. I
think "A" was the hotter side. The original source label was a thin metalic
self-adhesive foil placed around the circumference of the disk, but they
were easily pealed off. The meters and sources were also distributed under
the Searle Analytic name (they bought out NC). Some also may have been
distributed under the Texas Nuclear name as they were owned by NC. Its also
possible that Amersham distributed some of these meters & sources, as they
were also owned for a while by Searle too.  I usually refer to the sources
as grey hockey pucks. Check with state authorities about these, they are
probably still in the exempt source registration books somewhere. Nuclear
Chicago, Searle Analytic, and Amersham Searle were all licensees in
Illinois. You might check with the Illinois Department of Nuclear Safety
(217) 785-9900. Paul Eastvold, once in charge of the rad material section,
might remember something about them.

Dave Derenzo
University of Illinois at Chicago
Dave@uic.edu

Date: Wed, 12 Nov 97 10:49:57 CST
>From: "Dale E. Boyce" <dale@radpro.uchicago.edu>
>To: radsafe@romulus.ehs.uiuc.edu
>Subject: Re: "Nuclear B" disk
>Message-ID:  <9711121049.aa03241@radpro.radpro.uchicago.edu>
>
>Ralph,
>
>The only thing I have seen similar to what you describe were small
>radium sources.  The ones I saw were medium gray, between a nickel
>and a quarter in diameter and perhaps 3/16" thick.  If memory serves,
>and it sometimes mutates, I think these sources usually were associated
>with a gray colored survey instrument that had a compartment to store
>the source.  I don't remember much more about the brand, etc, but
>maybe this will help jog someone else's memory.  Good luck.
>
>Dale