Medidas de exhalación de radón 222 del tufo volcánico ecuatoriano usado como material de construcción

Abstract

This curricular integration work is related to natural radioactivity, specifically with the quantification of radon-222 exhalation rates of seven samples of volcanic tuff, used as construction material, the samples were collected in quarries of stone material, located in the provinces of Chimborazo, Tungurahua, Cotopaxi, and Pichincha. The samples were analysed with the closed chamber technique, whose experimental setup consisted of a scintillation detector (Lucas cell), incorporated into the Pylon AB monitor, and a 125-litre tempered glass chamber. Experiments performed to characterise the chamber in the Nuclear Techniques laboratory of the ESPOCH Science Faculty showed that it has a low leak rate, is not thermally insulated, and has a radon background compatible with the laboratory. The mass exhalation rates of the seven tuff samples presented values below the detection level of the technique, except for the three samples from the El Salvador quarry that exhaled in the range of 0.041 to 0.050 Bq/kg h. For one of the samples from the El Salvador quarry, the surface exhalation rate was determined (1.27 ±0.028 Bq/m2 h), which is equivalent to a dose of (0.15 mSv/y), a value lower than that recommended by the International Commission on Radiological Protection (ICRP) (1 mSv/y). The analysis of samples of volcanic origin is recommended as there is a high probability of radioactivity in this type of material.