Implications for analysis of (226)Ra in a low-level gamma spectrometry laboratory due to variations in radon background levels.

The background spectrum of HPGe detectors is found to vary significantly as function of the radon concentration in the air surrounding it, especially with regard to the count rates of (222)Rn daughter peaks. This effect is shown to potentially have a large impact on measured values of radon daughter activity concentration, as well as detection limits for low-level measurements. As these radionuclides are commonly used for estimating the activity of (226)Ra, care needs to be taken to ensure that background levels are accurately determined.