What term describes radioactive particles that contaminate surfaces where they are not supposed to be?

The term that describes radioactive particles that contaminate surfaces where they are not supposed to be is "contamination." This occurs when radioactive materials are unintentionally deposited on surfaces, which can happen through various means such as spills, aerosolization, or accidental release. Contamination differs from exposure, which refers to the amount of radiation that individuals come into contact with but does not imply the presence of radioactive materials on surfaces.

Contamination can be a serious concern in radiological safety because it poses a risk to human health and the environment. It may require special cleaning procedures and monitoring to ensure the area is safe again.

Ionization refers to a process where atoms or molecules gain or lose electrons, resulting in charged particles, which is a separate phenomenon related to the effects of radiation but not specifically about particles residing on surfaces. Decay refers to the process by which unstable atomic nuclei lose energy by emitting radiation, contributing to the natural decline of radioactive materials but not directly addressing the issue of particles contaminating surfaces.