Which type of device operates by the process of adsorption and measures gamma decay?

The device that operates by the process of adsorption and measures gamma decay is activated charcoal devices. These devices utilize a layer of activated charcoal as the medium to capture radon gas from the environment. The adsorbed radon undergoes radioactive decay, emitting alpha particles and gamma radiation in the process.

In the case of activated charcoal, the adsorption process is crucial because it allows the radon gas to adhere to the surface of the charcoal particles, thereby concentrating the radon over a specified measurement period. After this exposure, the charcoal is sent to a laboratory for analysis, where the amount of radon decay products is evaluated, allowing for the measurement of radon levels.

Understanding the operation of activated charcoal devices is important for interpreting radon measurement results, especially since they are commonly used for short-term and long-term testing.