What does the SI unit C/kg measure in the context of radiation?

The SI unit of C/kg, or coulombs per kilogram, measures exposure to ionizing radiation in air. This measurement quantifies the amount of ionization produced by radiation as it interacts with air. Specifically, it reflects the total charge of ion pairs produced in a specified mass of air, which is essential for understanding radiation exposure effects and ensuring safety protocols.

In the context of radiological practices, understanding exposure in air is critical because this is typically where radiation is measured and monitored before it reaches biological tissues. The relationship to air is important, as it serves as a medium for the ionization process to occur, facilitating the calculation of the biological effects of the radiation once it enters the body.

Other units mentioned, like radiation absorbed dose, measure energy deposited in a specific material, and biological equivalent dose relates to health risks and varying tissue sensitivities to radiation. Ionizations inside a medium describes the interaction but is not expressed as C/kg. Understanding these distinctions helps clarify why C/kg specifically pertains to exposure in air.