Radiation Safety Practice Exam

Which of the following instruments is commonly used to detect and measure ionizing radiation?

1. Thermal imaging camera

2. Liquid scintillation counter

3. Ultrasonic detector

4. Infrared thermometer

The correct answer is: Liquid scintillation counter

The liquid scintillation counter is a widely utilized instrument for detecting and measuring ionizing radiation due to its specific design and functionality. This device detects radiation by utilizing the principle of scintillation, where certain materials emit light when they interact with ionizing radiation. The emitted light is then captured and converted into an electrical signal that can be quantified and analyzed. Liquid scintillation counters are particularly effective for measuring low levels of β-particles and for applications involving radioactive isotopes in a liquid phase, making them highly relevant in fields such as health physics and nuclear medicine. Their sensitivity and ability to measure disintegrations per minute (DPM) allow for precise quantification of radioactive samples. In contrast, the other instruments listed have different purposes. Thermal imaging cameras are used to detect heat radiation rather than ionizing radiation. Ultrasonic detectors are designed to detect sound waves and are not suitable for measuring radiation. Infrared thermometers measure temperature using infrared radiation, which is entirely different from ionizing radiation. Understanding the specific applications of each device helps clarify why the liquid scintillation counter stands out as the appropriate choice in this context.