Comparison of Radon Mass Exhalation Rate Measurements from Building Materials by two Different Methods

TL;DR

This study compares two methods for measuring radon exhalation rates from granite building materials, finding consistent results and significant reductions in exhalation from coated samples.

Contribution

It provides a comparative analysis of passive and active radon measurement techniques on coated and uncoated granite samples.

Findings

Radon exhalation rates ranged from 11 to 45 mBq/kg/h.

Coated samples showed about four times lower exhalation rates.

Both measurement methods yielded consistent results.

Abstract

The aim of this study is to measure the radon mass exhalation rate from common granite building materials used in the East and Northeast part of Portugal. Twelve cubic shaped samples were measured. Nine of them without any coating and three coated with different materials (varnish,hydrorepellent and liquid silicone). The radon measurements were performed with two different techniques: one using passive detectors and other using an active detector. For the passive method CR-39 solid state nuclear track detectors were used. The active method used the RAD7 DURRIDGE detector. Radon mass exhalation rates obtained from both methods present relatively low values in the 11 to 45 mBq/kg/h range for the analyzed samples. Concerning the coated samples, the measured values are on average four times lower than the ones without coating. Overall, the measured values for both methods present a good agreement.