Speaker
Description
The aim is to estimate the adsorption capacity of Radon and Thoron on zeolites in order to reduce their activity in indoor environments and/or to develop a new measurement method. From a chemical point of view, Radon (Rn-222) and Thoron (Rn-220) are equivalent, therefore the adsorption process is similar. In our experiment we used thoron from the decay chain of Th-232, which often plays an important role in indoor radon monitoring. Its half-life is very short, about 55.6 s. Its progeny sometimes contributes significantly to the radiation dose in residential buildings.
Zeolites have a well-defined three-dimensional porous structure and good radiation resistance. The size and shape of the pores are crucial for the trapping of gas atoms. Various natural and synthetic zeolites are used and evaluated for their adsorption efficiency. The study then focused on the chabazite type and zeolite 4A. The experimental work was carried out in a thoron exposure chamber where the gas diffuses uniformly and is monitored by an α-spectrometry device based on the electrostatic collection of thoron progeny. γ spectrometry, based on a hyperpure germanium detector, was used to characterize the zeolite before and after thoron exposure in order to estimate its adsorption capacity. The results are encouraging and will certainly contribute to the development of better radon removal materials and the establishment of standardized measurement techniques for routine radon monitoring.