Science
Alpha Decay: Unpacking Radioactive Transformation
An explainer on alpha decay, a type of radioactive decay where an atomic nucleus emits an alpha particle, changing into a new element.
What is it?
Alpha decay is a type of radioactive decay where an unstable atomic nucleus emits an alpha particle to become more stable. An alpha particle is identical to the nucleus of a helium-4 atom, consisting of two protons and two neutrons. When a nucleus undergoes alpha decay, its mass number decreases by four, and its atomic number decreases by two, transforming it into a different element. For example, uranium-238 decays into thorium-234 through this process. This type of decay typically occurs in heavy elements with atomic numbers greater than 82, such as uranium, radium, and thorium.
Why is it trending?
The principles of alpha decay are fundamental to various modern technologies and scientific research. Alpha emitters are crucial components in household smoke detectors, where they ionize air to detect smoke particles. In the medical field, targeted alpha therapy (TAT) is a promising cancer treatment that uses alpha-emitting isotopes like Radium-223 and Actinium-225 to destroy cancer cells with minimal damage to surrounding tissue. Furthermore, alpha decay provides a reliable power source for radioisotope thermoelectric generators (RTGs) used in space probes and artificial heart pacemakers.
How does it affect people?
Alpha particles are relatively heavy and slow, with low penetrating power; they can be stopped by a sheet of paper or the outer layer of skin. This means external exposure is generally not harmful. However, if an alpha-emitting substance is inhaled, ingested, or enters the body through a wound, it becomes highly dangerous. Inside the body, alpha particles can cause significant damage to cells and DNA in a very localized area, increasing the risk of cancer and other health issues. For instance, inhaling radon gas, a natural alpha emitter, is a known cause of lung cancer.