Key Stage 5
Meaning
Alpha decay is a type of radioactive decay where an unstable nucleus emits an alpha particle consisting of two protons and two neutrons.
About Alpha Decay
- Reduces the Atomic Number atomic number by 2 and the mass number by 4.
- Common in heavy elements like uranium and radium.
- Alpha particles have low penetration depth but high ionizing power.
- Alpha decay is a form of spontaneous fission.
The emitted alpha particle is a helium nucleus (He²⁺).
- Alpha decay results in a daughter nucleus that is more stable than the parent.
The energy released during alpha decay is in the range of 4-9 MeV.
- Alpha decay can be detected using Geiger-Müller counters or scintillation detectors.
Examples
- Radium-226 decays to radon-222 by emitting an alpha particle.
- Smoke detectors often use americium-241, which undergoes alpha decay.