The Differences between Alpha, Beta and Gamma Radiation
- Alpha, beta, and gamma radiation are three types of radioactive emissions, each with different properties and behaviours.
- Alpha particles: Composed of two protons and two neutrons, basically a Helium nucleus. They are positively charged and here are a few characteristics:
- High ionising power: Because of their large size, alpha particles collide with many atoms and ionise them.
- Low penetrating power: Alpha particles cannot travel far in air and are stopped by a few cm of air or a sheet of paper.
- Alpha particles have a deflexion towards a negatively charged plate in a magnetic field, because of their positive charge.
- Beta particles: They are high speed electrons (or positrons) ejected from the nucleus. Beta particles have these properties:
- Medium ionising power: Beta particles are smaller and faster than alpha particles, meaning they collide with fewer atoms, ionising less frequently.
- Medium penetrating power: Beta particles can penetrate further than alpha particles and can be stopped by a few millimetres of aluminium.
- Beta particles deflect in the opposite direction of alpha particles in a magnetic field, due their negative charge.
- Gamma rays: These are electromagnetic waves and not particles. They behave differently compared to alpha and beta particles:
- Low ionising power: As they are waves, gamma rays do not have mass or charge, so they do not ionise other atoms frequently.
- High penetrating power: Gamma rays can travel large distances and pass through most materials, including the human body. Lead or several metres of concrete are needed to adequately shield against them.
- Gamma rays are not deflected by magnetic fields as they do not have a charge.
It’s crucial to grasp these differences as they impact how each type of radiation is used, and how they can be shielded or detected. Each type of radiation also affects biological tissues differently, influencing the degree of harm to living organisms.