What type of detectors are commonly used in survey meters for checking radiation levels?

Gas filled detectors are commonly used in survey meters for checking radiation levels due to their sensitivity and ability to measure ionizing radiation across a range of energies. These detectors work by allowing radiation to ionize the gas within a chamber, which creates free charges that can be collected and measured. This results in a current or count that corresponds to the intensity of the radiation present.

The design of gas filled detectors makes them particularly effective for radiation measurement purposes, including alpha, beta, and gamma radiation, depending on the type of gas and detector configuration used. Their robustness and relative simplicity also contribute to their widespread use in various applications, including environmental monitoring and radiation safety assessments.

In contrast, optical detectors, thermal detectors, and liquid crystal detectors are used for different purposes and do not provide the same level of effectiveness for measuring ionizing radiation, making them less suited for use in survey meters designed to monitor radiation levels.