Analysis of radon progeny contamination

ABSTRACT

In the present work, the radon contamination has been investigated with a high-purity germanium detector and dual ‘gamma + beta’ and ‘alpha’ contamination metre. Radioactive radon (²²²Rn) and products of its decay were collected by well-known swiping technique. Naturally occurring dust deposited on a plastic surface was collected and the radiation emissions coming from the collected sample were measured and analysed. The main radioactive isotopes contributing to the gamma spectrum were determined. The time behaviour of radon progeny contributing to gamma and alpha activities was investigated and compared with a modelled forecast. The minimal detectable activity when the radon progeny could be determined with a high-purity germanium gamma spectrometer has been established. Also, the minimum activity, measured with a dual contamination metre, has been recognised at which the presence of radon progeny contamination can be determined using gamma spectrometry. A new method is proposed for determining the duration of radon contamination and the time when the contamination occurred. The method is based on the analysis of the relative gamma activities of radon progeny (²¹⁴Pb and²¹⁴Bi) measured at different times after the radon contamination.

KEYWORDS:

• Radon progeny
• contamination
• gamma spectrometry
• radioactive pollutants

Acknowledgments

The author would like to thank Dr. G. Swan, T. Heale and P. McMillan of Canadian Nuclear Laboratories for their assistance and support in collecting experimental data and discussing them.

Disclosure statement

No potential conflict of interest was reported by the author(s).