What unit is used to express occupational exposure in radiation protection?

The unit used to express occupational exposure in radiation protection is the Sievert (Sv). The Sievert measures the biological effect of radiation on human tissue, taking into account the type of radiation and its impact on health. It provides a standardized way to quantify the potential damage from different types of radiation exposure, making it particularly relevant for assessing occupational risks for workers in environments where they are exposed to ionizing radiation.

Other units listed have different applications. The Gray (Gy) measures the absorbed dose of radiation, indicating the amount of energy deposited per unit mass but does not account for the biological effects. The Röntgen (R) is an older unit that specifically measures exposure to ionizing radiation in air but is less commonly used in occupational health contexts today. The Curie (Ci) measures radioactivity, defining the quantity of a radioactive substance but does not relate directly to biological effects or exposure levels for humans. Therefore, Sievert's focus on biological impact makes it the appropriate choice for expressing occupational exposure in radiation protection.