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Re: taking apart smoke detectors

I think Tim is wrong on this one. While the Am-241 is incorporated
in a metal foil structure, I believe that it is in the form of an oxide
deposit that may be covered with at most a thin film of material (otherwise
the alpha particle would not be able to enter the ionization chamber). This
means that it ought to be quite easy to dislodge some of the oxide by
scraping the foil with a sharp tool. The major hazard would be if some of
the americium oxides become airborne and attached to fine particles that can
be inhaled. Some of these would stay in the lungs....

Mark

-----Original Message-----
From: Tim Sullivan x5830 [SMTP:sullivan@KENYON.EDU]
Sent: Thursday, April 22, 1999 4:35 PM
To: PHYS-L@LISTS.NAU.EDU
Subject: Re: taking apart smoke detectors

Mark Shapiro wrote:

I would caution strongly against removing alpha sources from smoke
detectors. The inhalation of alpha emitting material is a serious hazard
to
one's health.

Mark Shapiro


There may be several reasons why taking apart smoke detectors is a bad
idea,
but, as may have been mentioned before in this
thread, the radioactive material is incorporated into the body of a metal
foil
and is not an inhalation hazard.

Several people have expressed worries about lawsuits in regard to giving
students experience with radioactivity. It is ironic that electrical shock
is
surely a greater hazard in physics labs than reasonably designed radiation
labs. I have been following in the news a hopeful innovation in the law
that
has a chance of returning the legal system to some sense of sanity in
regard to
scientific questions. It seems that the courts are moving to a system of
appointing impartial experts to put the technical issues into the context
of
mainstream science. Based on the advice of the expert, judges can exclude
the
testimony of fringe scientific opinions.

Tim Sullivan
sullivan@kenyon.edu