Radioisotopes in Smoke Detectors Chemistry Tutorial
- An ionization smoke detector contains:
⚛ a positive electrode
⚛ a negative electrode
⚛ a radiation source
⚛ a current detector
- The radiation source is an unstable isotope such as americium-241
- An unstable isotope undergoes nuclear decay (radioactive decay) by emitting radiation.
- Normally, charged particles in the air allow a current to flow through the detector.
Smoke particles in a fire prevent the current flowing causing an alarm to sound.