Which unit is used to measure exposure to radiation?

The unit that is primarily used to measure exposure to radiation is the Roentgen (R). This unit quantifies the amount of ionization produced in air by x-rays or gamma rays. When we speak of exposure, we are specifically referring to the radiation dose delivered to air, emphasizing its capacity to cause ionization and act as a measure of radiation's potential biological effects as it interacts with the air.

The Roentgen is used in practical situations to understand the level of radiation one may encounter in an environment, such as during occupational exposure assessments. It helps professionals ensure safety measures are adequate under regulatory limits and allows for effective monitoring of working conditions.

Other units serve different purposes: the rem (or millirem) is utilized for evaluating biological effects of radiation in living tissue, the curie relates to radioactivity itself, and the gray measures absorbed dose in tissue. Each unit plays a unique role within radiological science, but for direct exposure measurements, the Roentgen is the appropriate choice.