Radiation dosimeters operate on which x-ray characteristic?

• A. Absorption
• B. Ionization
• C. Reflection
• D. Refraction

Answer: (B)

Radiation dosimeters rely on ionization. When x-rays pass through the detector gas, they ionize gas molecules, producing ion pairs. An electric field collects these charges, and the resulting current is proportional to the amount of ionization, which correlates with the radiation dose. This is the fundamental mechanism for common dosimeters like ionization chambers. Absorption relates to energy deposited, but dosimeters measure the ionization produced, not direct energy absorption; reflection and refraction are optical phenomena and do not apply to detecting ionizing radiation.