Final answer:
Ionization is one of the two types of fire detection technologies used in smoke detectors. In an ionization smoke detector, a small amount of radioactive material emits alpha particles that ionize the air between two electrode plates.
Step-by-step explanation:
One of the two types of fire detection technologies used in smoke detectors is ionization.
In an ionization smoke detector, a small amount of radioactive material, such as americium-241, emits alpha particles that ionize the air between two electrode plates in the ionizing chamber. A battery supplies a potential that causes movement of the ions, creating a small electric current. When smoke enters the chamber, the movement of the ions is impeded, reducing the conductivity of the air and causing a drop in the current, which triggers the alarm.
Smoke detectors with this technology utilize a small amount of the radioactive element Americium-241, which is an alpha (α) emitter. The alpha particles from Americium-241 ionize the air between two electrode plates inside the ionization chamber, allowing a small electric current to flow. When smoke enters the chamber, it disrupts this flow of ions, causing a significant reduction in the electrical current. This drop in current activates the detector's alarm, signaling the presence of smoke and potential fire.