How is a radiation measurement acquired by an ionization chamber?

The correct choice indicates that radiation measurement is acquired by ionizing the air in the chamber, which is fundamental to how an ionization chamber operates. When ionizing radiation, such as alpha particles, beta particles, or gamma rays, passes through the ionization chamber, it interacts with the air molecules inside the chamber. This interaction dislodges electrons from the air molecules, creating positive ions and free electrons in the process.

The generated charge (the free electrons and positive ions) is collected by applying a voltage between two electrodes within the chamber. As the charge accumulates, it creates a measurable current that correlates with the radiation intensity present in the chamber. Therefore, the ionization process is crucial because it transforms the energy from the incoming radiation into an electrical signal that can be quantified.

This mechanism of ionization is specifically designed to measure radiation; it's a distinct process that does not involve detection of sound waves, light intensity, or temperature changes, which would not effectively indicate radiation levels. Thus, the choice that highlights ionizing the air in the chamber is correct and reflects fundamental principles of radiation detection using this technology.