Thermal and structural properties of magnesium tetraborate produced by solid state synthesis and precipitation for use in thermoluminescent dosimetry

Publication date: Available online 24 June 2019Source: Radiation Physics and ChemistryAuthor(s): Luiza Freire de Souza, Linda V.E. Caldas, Danilo O. Junot, Anderson M.B. Silva, Divanizia N. SouzaAbstractMagnesium tetraborate is a phosphor with relevant characteristics for radiation dosimetry purposes. One of the main challenges on this material is still the understanding of its structure and luminescent processes involved in dosimetric performance. In this work, all the steps of the material production through DTA/TG, XRD and SEM techniques were evaluated to understand the main physical and chemical changes during the thermal process (calcination and sinterization) to produce the MgB4O7 samples. Two synthesis processes of MgB4O7 were studied: precipitation (P.S) and solid state (S.S). Finally, the luminescence efficiency of the pellets was investigated in function of different sintering temperatures. The initial stage of DTA/TG curves of the material just after the mixing of starting materials, regardless the synthesis, is marked by endothermic events caused by dehydration, decomposition of hydroxyl groups and hydrated borate phases. At higher temperatures, the curves are marked by exothermic events related to crystalline transitions, but the peak obtained for the S.S is better defined in comparison to P.S. Moreover, the DTA/TG analyses of the pellets prior and after the sinterization, showed that the process is more relevant for the MgB4O7 pellets produced by S.S (950 °C)...

Source: Radiation Physics and Chemistry - June 25, 2019 Category: Physics Source Type: research