Propriedades físico-químicas de vidros boratos de cálcio e sódio dopados com lantânio para dosimetria de radiação

Abstract

Borate glasses are materials that exhibit promising and interesting dosimetric characteristics. In addition to thermoluminescent characteristics, it has low production costs, ease of preparation and effective atomic number close to that of human tissue. This set of attributes enables its application in radiation dosimetry. In this type of material, the introduction of rare earth elements as dopants has shown an important role in improving some properties. This work aims to analyze some structural, optical and dosimetric properties of glass samples prepared by melting and molding, according to the system (100 - y) (67B2O3 - 28CaO - 5Na2O) – y La2O3, with y = 0.0; 0.1; 0.3; 0.5 and 0.7 mol% of lanthanum oxide to verify the potential for application as an ultraviolet radiation dosimeter. X-ray diffractometry, density, molar volume, optical absorption spectroscopy in visible ultraviolet (UV-Vis) and mid-infrared Fourier transform (FT-IR) analyzes were carried out, ending with thermoluminescence measurements. X-ray diffractometry confirmed the non-crystalline structure of the glass sample and the absence of crystallization peaks. Density and molar volume analyzes identified that density increases from percentages above 0.3% mol of lanthanum. The FT-IR and UV Vis spectra showed that the introduction of lanthanum did not cause changes in the glass structure, nor in the value of the band gap energy. The thermoluminescent emission curves did not change with the different particle sizes evaluated. In the calibration curves it was possible to notice that there was an enlargement of the linear region, but this improvement was not directly proportional to the percentage of the added dopant. The CaNaBO5:0.1La and CaNaBO5:0.7La samples presented promising results for application in dosimetry, after analyzing the calibration, reproducibility and thermal and optical decay curves.