Which of the following is a common device used for measuring ionizing radiation?

The Geiger-Muller (GM) counter is a widely recognized device for measuring ionizing radiation due to its ability to detect and quantify the presence of radiation in various environments. It operates by using a Geiger-Muller tube filled with gas that becomes ionized when radiation passes through it. This ionization causes a cascade of electrical pulses that are counted, allowing users to measure the radiation levels. The GM counter is particularly valued for its sensitivity, ease of use, and ability to provide immediate readings of radiation levels, making it an essential tool in environmental monitoring, health physics, and nuclear industry applications.

While other devices like dosimeters and radiometers are also used in radiation measurement, they serve different specific purposes. Dosimeters are designed to measure an individual's cumulative exposure to radiation over time, often worn on a person's clothing, while radiometers typically measure non-ionizing radiation or can refer to specialized instruments measuring specific types of radiation. A thermometer, on the other hand, quantifies temperature and is not useful for radiation measurement.