Americium-241


 * Uses or Radioactive Isotopes

Americium-241 in Smoke Detectors**

The element Americium is synthetically created by bombarding plutonium with neutrons in a nuclear reactor. Its isotope, Am-241 decays by emitting alpha particles and gamma radiation to become neptunium-237. The most common household smoke detectors use a very small quantity of Am-241 (about 0.29 micrograms per smoke detector) in the form of Americium dioxide. The smoke detectors use the Am-241 since the alpha particles it emits collide with oxygen and nitrogen particles in the air. This occurs in the detector's ionization chamber where it produces charged particles or ions. Then, these charged particles are collected by a small electric voltage that will create an electric current that will pass between two electrodes. Then, the ions that are flowing between the electrodes will be neutralized when coming in contact with smoke, therefore decreasing the electric current between the electrodes, which will activate the detector's alarm.

http://www.world-nuclear.org/info/inf57.html



Fun Fact:

Steps for creating Americium-241  The plutonium-241 is formed in any nuclear reactor by neutron capture from uranium-238. U-238 + neutron => U-239 U-239 by beta decay => Np-239 Np-239 by beta decay =>Pu-239 Pu-239 + neutron => Pu-240 Pu-240 + neutron => Pu-241 This will decay both in the reactor and subsequently to form Am-241.
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