Re: Accident with Am-241 smoke detectors

[Dave Derenzo <dave@uic.edu>]

A long time ago (1970's), a lab I worked in tested smoke detectors for 
U.L.  The sources described by Dr. Raabe are Am-241 sandwiches, a layer of 
gold (maybe platinum, my memory fails me on this) was rolled out, a layer 
of Am-241 was added, and another layer of gold was rolled over the 
Am.  Individual sources are cut out of a large in sheet cookie cutter 
fashion, and mounted in a holder.  A great number of this type were made by 
Amersham.  These sources were very leak resistant.  Other sources, however, 
were electroplated.  They had a greater possibility for release of the 
Am-241, especially if you twisted or flexed the source when removing it 
from the detector.  In those days, some smoke detectors contained 
Ra-226.  I think that most of the Am-241 sources contained about 10 
uCi.  Some of the Ra-226 sources contained quite a bit more, but I don't 
remember how much.

Dave Derenzo

At 10:30 AM 02/17/2000 -0600, you wrote:
>February 17, 2000
>Davis, CA
>
>The person who opposes the use of Am-241 in smoke detectors probably
>imagines that the Am-241 is escaping into the air in his house and
>poisoning his family.
>
>The Am-241 sources in smoke detectors are so well sealed in a metallic gold
>covered disk that even when one was accidently swallowed by an assembly
>worker (I believe reported in the HPS Journal or Newsletter), it passed
>through the GI tract with no measurable release of Am-241 into the body.
>These are superbly sealed and safe sources as currently manufactured. There
>is no scientific basis for the reported concerns.
>
>Otto
>
>                 *****************************************************
>                 Prof. Otto G. Raabe, Ph.D., CHP
>               Institute of Toxicology & Environmental Health (ITEH)
>                    (Street address: Building 3792, Old Davis Road)
>                 University of California, Davis, CA 95616
>                 Phone: 530-752-7754  FAX: 530-758-6140
>                 E-mail ograabe@ucdavis.edu
>               *****************************************************
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Dave Derenzo (dave@uic.edu)
UIC Radiation Safety Section, M/C 932
Phones: Voice (312) 996-1177  Fax: (312) 996-8776

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