Which radon measurement device uses an electrically charged electret?

The electret ion chamber detector is designed to utilize an electrically charged electret to measure radon levels in the environment. In this device, the electret acts as a sensitive detector that responds to ionization caused by radon decay products. When radon gas is present, it emits alpha particles as it decays, which in turn ionizes the air inside the chamber. This ionization process alters the charge on the electret, allowing for a measurable change that correlates to the concentration of radon in the air.

This method is particularly effective because it can provide a passive and long-term measurement without needing a continuous power supply, unlike other devices that require electronic components to operate continuously. By utilizing the physical properties of the electret, this type of radon measurement can be both accurate and reliable for assessing radon exposure in residential or commercial settings.