Alfasäteilyyn

Alfasäteilyyn is the Finnish term for alpha radiation. Alpha radiation consists of alpha particles, which are helium nuclei. Each alpha particle is composed of two protons and two neutrons, giving it a positive charge of +2e. Due to their composition, alpha particles are relatively massive and carry a significant amount of kinetic energy when emitted.

Alpha particles are produced during a type of radioactive decay called alpha decay. This process occurs in heavy atomic nuclei that are unstable. When an unstable nucleus undergoes alpha decay, it emits an alpha particle, transforming into a different element with an atomic number two less than the original. For example, uranium-238 decays into thorium-234 by emitting an alpha particle.

The penetrating power of alpha radiation is quite low. They can be stopped by a sheet of paper or a few centimeters of air. However, if an alpha-emitting substance is ingested or inhaled, the alpha particles can cause significant damage to internal tissues. This is because the energy deposited by the alpha particle is concentrated in a very small volume, leading to intense ionization.

Alpha radiation is used in various applications, such as smoke detectors and certain types of pacemakers. In smoke detectors, an alpha source ionizes the air, creating a current. Smoke particles disrupt this current, triggering the alarm. The low penetrating power makes alpha emitters safe for these applications as long as the radioactive material is contained.