SILAS CARDOSO DOS SANTOS
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Artigo IPEN-doc 30865 Effect of thulium on promotion of dose-response behaviour of yttria based rods by Electron Paramagnetic Resonance2024 - SANTOS, S.C.; RODRIGUES JUNIOR, O.; CAMPOS, L.L.Artigo IPEN-doc 25136 EPR response of yttria micro rods activated by europium2018 - SANTOS, S.C.; RODRIGUES JUNIOR, O.; CAMPOS, L.L.Rare earth (RE) materials present excellent properties, which importance is recognized worldwide. Innovation approaches in energy, medicine, communication, transportation, militarism, and radiation dosimetry consist in RE based materials. As yttrium oxide (Y2O3) exhibits intrinsic lattice characteristics that enable doping with others RE elements (Y2O3:RE), new materials with promising characteristics can be developed. This work aims to evaluate EPR response of europium-yttria (Y2O3:Eu) rods obtained by bio-prototyping. Ceramic rods containing up to 10 at.%Eu were irradiated with gamma doses from 0.001 to 150 kGy and evaluated by Electron Paramagnetic Resonance (EPR) at room temperature with X-band EPR. Based on results, Y2O3:Eu rods with 2 at.%Eu exhibited the most significant response, in which linear behavior arose from 0.001 up to 50 kGy. Fading and thermal annealing evaluations revealed that 2 at%.Eu improved dosimetric characteristics of yttria remarkably. These innovative findings afford that Y2O3:Eu is a promising material for radiation dosimetry.Artigo IPEN-doc 24787 EPR dosimetry of yttria micro rods2018 - SANTOS, S.C.; RODRIGUES JUNIOR, O.; CAMPOS, L.L.The use of rare earths (RE) as dopant of materials has led the development of advanced materials for many applications such as optical tracers, special alloys, semiconductors, as well as radiation dosimeters. The development of new dosimetric materials based on REs is a great challenge in innovation of materials. Yttria (Y2O3) presents luminescent proprieties and is a promising material for radiation dosimetry. The present paper aims to evaluate paramagnetic defects of Y2O3 rods obtained via bio-prototyping by using Electron Paramagnetic Resonance (EPR) technique at room temperature. Ceramic rods were irradiated with gamma doses from 0.001 to 150 kGy and evaluated by EPR at room temperature with X-band EPR. According to EPR results, as sintered samples exhibited an EPR signal with principal g tensor of 2.020 and maximum line width around 2.3 mT, which is ascribed to interstitial oxygen ion. Dose response behaviour exhibited two distinct dose ranges, one is from 1 to 100Gy and the second is from 0.1 to 70 kGy. Thermal annealing approaches reveal that defect centres of yttria decay significantly at high temperature. These innovative results make Y2O3 a promising material for radiation dosimetry.