Which type of ionizing radiation is the most penetrating?

Gamma rays are the most penetrating type of ionizing radiation due to their very high energy and lack of mass and charge. Unlike alpha particles and beta particles, which can be blocked or attenuated by relatively thin materials (alpha particles can be stopped by a piece of paper, while beta particles require thicker materials like plastic or aluminum), gamma rays can penetrate through most substances easily.

Their ability to pass through materials is largely due to their electromagnetic nature, which allows them to traverse large distances without interacting with matter very much. This results in gamma rays being able to penetrate human tissue and shielding materials much more effectively than alpha and beta particles.

Neutrons, while also being penetrating, require materials rich in hydrogen, like water or polyethylene, for effective shielding, which makes gamma rays generally the most penetrating radiation type in a broader range of materials. Understanding the penetrating ability of various radiation types is crucial for establishing safety protocols in settings involving radiation exposure, such as in industrial radiography.