What is an ionization chamber used for in radiation protection?

• A. To measure exposure rate and dose in air; used for surveys and instrument calibration.
• B. To detect alpha contamination on surfaces.
• C. To measure neutron flux.
• D. To read tissue dose directly.

Answer: (A)

Ionization chambers are gas-filled detectors that measure the ionization produced by radiation in a known volume of air. The resulting current is proportional to the exposure rate in air, making them ideal for quickly quantifying environmental dose rates and for calibrating survey instruments.

This is why they’re used for area surveys and instrument calibration—providing a direct, reliable readout of how much radiation is present in the environment. They aren’t the right tool for detecting alpha contamination on surfaces (that uses surface contamination or alpha-specific detectors), neutron flux (which requires neutron detectors with moderators), or reading tissue dose directly (which relies on tissue-equivalent dosimeters or other methods to relate air exposure to body dose).