[ RadSafe ] Two unrelated questions for the group

Robert D Gallagher rdgallagher at nssihouston.com
Fri Dec 2 12:15:30 CST 2005

The Am-241 sources used in smoke detectors are not sealed sources. The
sources are manufactured by mixing the Am-241 powder with a powdered  metal
such as gold and rolled into a very thin sheet. The sheet active sheet is
sandwiched between two sheets of soft metal and again rolled to form a
laminated sheet with non active metal on the outside and the active metal
sheet in the middle. When the rolling is completed, small discs are punched
from the laminate. These discs are the foils contained in the smoke

In the early days of smoke detectors, the various vendors subjected the
foils to all sorts of environmental tests including soaking them in
simulated human digestion system liquids to see if the Am-241 leached out.
As a result of these very extensive tests,the manufacturers were able to get
the NRC to authorize their distribution to the public as generally licensed

Numerous smoke detectors have been burned and otherwise mistreated. With
only a few exceptions, I am not aware of any that ever resuted in

Bob Gallagher
NSSI   Houston

-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl]On
Behalf Of Baumbaugh, Joel SPAWAR
Sent: Friday, December 02, 2005 10:39 AM
To: Radsafe (E-mail)
Subject: RE: [ RadSafe ] Two unrelated questions for the group


Question one: I have a Americium source from a smoke detector which
survived a wooden-building fire (I assume its double-walled stainless
steel?). I've swiped it and the LSC has never shown any leakage.  I
couldn't/wouldn't throw it away because out of the detector its no
longer exempt, so I use it as a check-source and a "show-and-tell" when
I train new users.

Just my 2-cents (my own personal observation).

Question 2: I can't help you with your other question although I'm very
interested in the projected/potential dose to the astronauts (both
in-flight and once they're on the ground) - I think that NASA's
discussed a specially shielded room to hover in, in case of solar

Joel Baumbaugh (baumbaug at nosc.mil)



I have two unrelated questions that I'm combining into one e-mail for


The first one has to do with Am-241 sources in smoke detectors.  What

happens when the smoke detector is burned in a building fire?  Is the

expected to survive intact or is there a potential for a release of some


Second question:

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