Alpha rays, also known as alpha particles, are a type of ionizing radiation. They consist of two protons and two neutrons, which are bound together and emitted from the nucleus of an atom. Alpha particles have a positive charge and are relatively large and heavy compared to other types of radiation.

Due to their size and charge, alpha particles have a limited range and can be easily stopped by a few centimeters of air or a sheet of paper. However, they can cause significant damage to living tissue if they are inhaled, ingested, or come into direct contact with the skin.

Alpha rays are commonly emitted by certain radioactive materials, such as uranium and radon. They can be detected and measured using specialized equipment, such as Geiger-Muller counters or alpha particle spectrometers.

In terms of their applications, alpha rays have been used in various fields, including scientific research, medical treatments, and smoke detectors. However, their potential health risks require careful handling and precautions to minimize exposure.