In what application are gases exposed to ionizing radiation useful?

Gases exposed to ionizing radiation are primarily useful in detection equipment. This stems from the fundamental principle that when ionizing radiation interacts with these gases, it produces ions and free electrons. These charged particles can then be measured, allowing the detection of radiation levels.

In applications such as gas ionization detectors (Geiger-Müller counters, for example), the ionized gas acts as the sensing medium. When radiation passes through the gas, it ionizes atoms, creating electron-ion pairs. The subsequent collection of these charges can be amplified to produce a measurable current, thereby indicating the presence and intensity of radiation. This principle is crucial in radiation monitoring and safety practices, making detection equipment reliable for assessing exposure levels and ensuring safety protocols are followed.

While other options such as medical imaging and radiation therapy may involve ionizing radiation, they do not specifically utilize gases exposed to radiation in the same way detection equipment does. Shielding materials, on the other hand, are designed to block radiation rather than detect it, which is another reason why detection equipment is the most appropriate choice in this context.