The content of americium is approx. 0,3 μg (37 Bq).
Americium-241 ionizes the air inside a smoke detector, making a small change in voltage when smoke is present.
Americium-241 is used in smoke detectors because it emits alpha particles that ionize the air inside the detector. This ionization process allows a small electric current to flow between two electrodes in the detector. When smoke enters the detector, it disrupts this current, triggering the alarm.
0,5 grams
The actinide used in some smoke detectors is americium-241. It emits alpha particles, which ionize the air inside the detector, causing a small electric current to flow. When smoke enters the detector, it disrupts this current, triggering the alarm.
In the smoke detector, the fast - moving alpha particles enable the air to conduct an electric current. As long as the electric current is flowing, the smoke detector is silent. The alarm is triggered when the flow of electric current is interrupted by smoke entering the detector.
Actually, americium-241 is not safe. If you disassemble the smoke detector and remove the americium-241 pellet, and then ingest it, you are at risk of developing cancer, because an alpha emitter is dangerous when ingested. There are clear warnings on the smoke detector about this. The reason smoke detectors in general are safe is that the amount of americium-241 is very small, and it is very difficult to extract it from the smoke detector. Also, the alpha particles will not travel more than an inch or so in free air, and they will be stopped by the internal design anyway, so the alpha particle field inside the smoke detector is limited to the ion chamber, also inside the smoke detector.
ionization smoke detector
Americium-241 is a radioactive isotope and used in smoke detectors to ionize the air (gives air molecules a charge). This allows a small current t flow between two contacts placed in the air chamber. When smoke particles enter the chamber, they attach themselves to the ionized molecules (by electrostatic attraction) effectively making them bigger and slowing the current. The detector then goes off when the current slows.
Americium-241 this is an emitter of alpha radiation, which is used in smoke detectors as it is very ionising and will not be able to travel through smoke. Therefore, in a fire the detector will not receive any alpha radiation and hence the alarm will go off.
Alpha radiation is emitted from the amercium button in a smoke detector. When smoke goes into the smoke detector it blocks the stream of alpha particles emitted from the americium. That triggers an alarm.
Americium has been used in smoke detectors since the 1950s. Its radioactive properties make it ideal for ionizing smoke particles in the detector, allowing it to quickly detect smoke and trigger the alarm.
Smoke detectors typically contain americium-241. This radioactive isotope is used to ionize the air in the detector, allowing it to detect smoke particles and trigger the alarm.