Americium
Contributor:听Alyson Lautar. Alyson is an undergraduate student of Pharmacy at UT and donated the smoke alarm.
8bet the Display:听Americium 241 is used in smoke detectors because it detects a wide range of fire conditions.
They are also less expensive and easier to install than their photoelectric counterparts.听
Americium releases alpha - particle, which can be measured at 0.9 micro-Curie. These
alpha particles collide with oxygen and nitrogen in the air to create charged particles,
or ions, in the detector's ionization chamber.
These ions are collected by a low level voltage that is applied across the chamber.
When the ions are collected, a small steady electric current flows between two electrodes.
If smoke reaches the detector, particles from the smoke will attach to the ions formed
from the alpha particles and oxygen or nitrogen. With fewer ions reaching their destination,
the electric current drops, triggering the alarm.
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Symbol:听Am
Atomic Number:听95
Atomic Mass:听243 u
Electron Configuration:听[Rn] 5f77s2
Year Discovered:听1945
Discovered By:听Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso