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Alpha particles from Am-241



On Monday, Sep 27, 2004, at 13:32 America/New_York, Bernard Cleyet
wrote:

Quite true -- UC has the license and I had to report such use to the
RSO
-- Actually I didn't need to as he supplied them to me knowing the use.

bc

Strickert, Rick wrote:

Am-241 from a, "ionization type" fire alarm
is a perfect source of alpha particles. The new
alarm costs $8 at Radio Shack. I removed the
source from an old alarm

According to 10 CFR 30.20
(http://www.nrc.gov/reading-rm/doc-collections/cfr/part030/part030-
0020.html), a person has an license exemption for possessing, using,
and transferring an Am-241 smoke detector. If the Am-241 source is
removed and used for another purpose, the person needs to have a
radioactive material license from the NRC or an Agreement State. The
license would cover aspects such as the use, storage, monitoring,
radiation safety, and disposal of the americium source in the
licensed facility.

Rick Strickert
Austin, TX

A smoke detector (ionization type, not photoelectric type) contains a
low intensity source of alpha particles. Information that follows is
from: < http://www.fbr.org/swksweb/radoncurriculum.html>
Ludwik Kowalski

==================================================

Americium (pronounced, "am-uh-RISH-ium" and named after America) was
the first man-made element. Glenn Seaborg and colleagues produced it by
neutron bombardment of Plutonium in 1944 while working on the Manhattan
Project at the University of Chicago. It is a shiny, malleable metal,
all isotopes of which are unstable. It has atomic number 95. Currently,
Americium-241 is produced by beta decay of spent Plutonium-241 in
nuclear reactors. It has a half-life of 432 years. The US Atomic Energy
Commission in 1962 first offered americium dioxide for sale for $1500
per gram and this price has remained essentially unchanged. Its major
use is as a source of alpha particles in the ionization chambers of
common smoke detectors, and one gram supplies enough Americium-241 for
5000 smoke detectors. Americium-241 is a potentially dangerous isotope
if it is taken into the body in soluble form as it can concentrate in
the skeleton and is both an alpha and a gamma emitter- potentially
causing DNA mutations. However, the dioxide in smoke detectors is
insoluble and even if ingested would pass harmlessly through the
gastrointestinal tract without delivering a significant dose of
radiation.