What unit of measurement is used for the ionization of air by X-rays or gamma rays?

The unit of measurement used for the ionization of air by X-rays or gamma rays is the Roentgen. This unit specifically measures the amount of ionization produced in air by X-ray or gamma radiation. The Roentgen is defined as the amount of X or gamma radiation required to produce one electrostatic unit of charge in one cubic centimeter of dry air at standard temperature and pressure.

Understanding the context is crucial. The Rad, for example, measures radiation absorbed dose, which indicates the amount of radiation energy absorbed by a material, but it doesn't specifically measure ionization. The Curie is a unit that measures the activity of radioactive material based on the number of disintegrations per second, making it unrelated to the ionization of air. The Sievert measures the biological effect of ionizing radiation on human tissue, taking into account the type of radiation and its impact on biological systems, rather than measuring ionization in air itself. Therefore, the Roentgen is the appropriate unit for this scenario, as it directly addresses air ionization by X-rays or gamma rays.