Radiation Safety Practice Exam

What is a significant limitation of hand-held survey meters regarding certain isotopes?

1. They cannot detect fast neutrons

2. They are ineffective on wet surfaces for alpha emitters

3. They only detect beta particles

4. They provide inaccurate readings in high radiation areas

The correct answer is: They are ineffective on wet surfaces for alpha emitters

Hand-held survey meters can indeed have limitations when it comes to detecting specific types of radiation under certain conditions. The identified limitation regarding their ineffectiveness on wet surfaces for alpha emitters is critical because alpha particles have a very low penetration ability. They can be stopped by a sheet of paper, and their detection often relies on direct contact with the target material. When surfaces are wet, the moisture can create a barrier that may obstruct the ability of the meter to detect alpha radiation effectively. Wet surfaces can cause alpha particles to have a reduced ability to reach the detector of the survey meter due to scattering or absorption by the moisture present. As such, this can lead to significant difficulties in accurately assessing the presence of alpha-emitting isotopes in contaminated environments. Other potential limitations exist regarding different types of radiation or conditions, but the specific challenge with wet surfaces highlights the need for careful consideration of environmental factors when using hand-held survey meters for radiation detection, especially for alpha emitters.