What source is used in smoke detectors?
Americium
About Americium in Ionization Smoke Detectors Ionization smoke detectors use americium as a source of alpha particles. Alpha particles from the americium source ionize air molecules. This makes some particles positively charged and some negatively charged.
Where can americium-241 be found?
Americium Sources Exposure to any significant amount of Am-241 is unlikely under normal circumstances. Small amounts of it are found in the soil, plants and water from nuclear weapons testing. Some smoke detectors contain very small amounts of Am-241.
What is Am-241 and how does it works as household smoke detectors?
The americium-241 in ionization chamber smoke detectors makes the air in the detector’s sensing chamber conduct electricity. When smoke enters the sensing chamber, it interrupts the electrical current, triggering the smoke detector’s alarm.
Why is alpha radiation used in smoke alarms?
An isotope of americium which emits alpha particles is used in smoke alarms. Alpha radiation ionises the air and this allows a small current to flow between two electrodes. Alpha is weakly penetrating so smoke stops it, the current drops and the alarm goes off.
Where does radium-226 come from?
Radium-226 is a decay product of the natural uranium-238 decay chain. It is present in all rocks and soils in variable amounts.
Why is americium 242 not used in smoke detectors?
How is AM 241 produced?
Americium-241 is produced in nuclear power plants during activation of 239Pu and 240Pu by neutrons, which is followed by beta decay of 241Pu (T1/2 = 14.35 years). This means that also in burned-up fuel 241Am is produced by decay of 241Pu a long time after the fuel is removed from a nuclear reactor.
Where is americium found?
Americium occurs naturally in uranium minerals, but only in trace amounts. The main source of the element is the neutron bombardment of plutonium in nuclear reactors.
How do radiation smoke detectors work?
How does smoke detector work?
The short answer. Smoke alarms detect fires by sensing small particles in the air using a couple of different kinds of technologies. Once they detect those particles above a certain threshold, they signal the alarm to sound so that you and your family can get to safety and call 911. Smoke alarms save lives.
