Which detector is most suitable for quick yes/no indication of radiation presence in the field?

• A. Ionization chamber is best for quick, presence-only checks.
• B. Geiger-Müller counter is best used for detecting presence and approximate strength of radiation.
• C. TLD provides real-time readouts.
• D. OSL dosimeter provides qualitative readings.

Answer: (B)

The key idea is choosing a detector that gives immediate, easy-to-interpret feedback for simply knowing whether radiation is present in the field. A Geiger-Müller counter is ideal for this because it detects individual radiation events and translates them into rapid pulses that you can hear or see, providing real-time indication of presence and a rough sense of strength. This makes it the practical choice when the goal is a quick yes/no determination rather than a precise dose-rate measurement.

In contrast, an ionization chamber is designed for accurate dose-rate measurements and can be more cumbersome in the field; it provides a quantitative readout but isn’t as immediate or user-friendly for a quick presence check. Passive dosimeters like TLDs or OSL devices don’t give real-time information—they require processing after exposure to yield a dose value, so they aren’t suitable for on-the-spot presence detection.

So, for a field survey where you just need to know if radiation is present (and get a rough sense of how much), the Geiger-Müller counter is the best fit.