Application of a “Sealed Can Technique” and CR-39 detectors for measuring radon emanation from undamaged granitic ornamental building materials

Abstract

Abstract. Radon ( 222 Rn) is the most important cause of exposure to mankind due to natural radioactivity. Radon exhalation depends not only on the 226 Ra concentration in the material, but also on other factors such as mineralogy of the region, size and density of grains and porosity of the material. As building materials are one of the major sources of environmental radon, the radiological implications of the use of materials with great content of uranium must be always assessed. In this work, radon exhalation from several undamaged granitic building materials used as ornamental rocks or coating tiles is determined using the "sealed-can technique" and CR-39 solid state nuclear track detectors (SSNTD). Preliminary results for radon concentrations showed values of the same order that literature values, in a range from 99 Bq.m −3 to 1100 Bq m −3 . Further, the methodology will be validated with standard sources of 222 Rn.

Determination of the activity concentration of 226Ra, 232Th, 40K and the concentration of 222Rn in soil samples of the Campos Gerais region (Paraná)

“…The determination of the radon activity concentration was performed using solid nuclear track detectors (SSNTD) by means of the Sealed can technique using a polycarbonate of domestic manufacture, as solid detector of nuclear tracks [25].…”

“…The results of the average of the radon determination triplicates of each sample, with the respective propagated uncertainty, are shown in Table 2. The track counts were performed manually after exposure to the natural radiation detector of the samples and treatment for the revelation of tracks [25]. In Table 2 it can be observed that the uncertainties associated with samples 3, 4, 5 and 6 were around 30%, an acceptable result considering the technique used and the fact that this technique is in the implementation phase.…”

Radiation hazard indices in the application of phosphogypsum mixtures as a building material: proposal for a Brazilian regulation

“…Such usage enhances the radon exhalation, since the distance for the radon to reach the outer surface is shorter [15].…”

“…The bulk usage of building materials tends to decrease the ratio between the 226 Ra concentration and the radon exhalation, since the gas can be trapped in the building material. In this case, the radon decays within the building structure, thus increasing the concentration of the short-lived gamma-ray emitting decay products [15]. Typical usage of materials like concrete, cement and natural gypsum falls in this category.…”

Determination of radon exhalation rates from soil around buildings in Lagos environments using passive measurement technique

“…Most of the emanated radon originates from radium found in shallow surface layers, up to a depth of the recoil range [10]. However, due to diffusion, these flows are notably reduced in wetter soils [11]. The rate at which the emanated radon escapes into the atmosphere is measured as the exhalation rates.…”