Samarium Doped Borophosphate Glasses and Glass-Ceramics for X-ray Radiation Sensing

Abstract

Samarium fluoride (SmF₃) and samarium oxide (Sm₂O₃) doped Zn- and Sr-borophosphate glasses with mixed oxide-fluoride matrix structures were prepared. The synthesized materials were studied by differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) to determine their glass transformation properties before and after various thermal treatments. X-ray diffraction (XRD) analysis was performed to characterize the structure, that is, whether the synthesized materials have a glass or polycrystalline structure, or is composed of a heterogeneous mixture. We observed that under certain conditions several post-treated materials are partially nanostructured, i.e. the formation of nanocrystals takes place within a glass matrix. The samarium doped materials were irradiated by different types of LEDs and laser light in the UV-NIR wavelength range to examine the photoluminescence (PL) induced and also to study the changes in the PL signal before and after exposure to high-dose X-ray synchrotron irradiation due to a possible reduction of Sm³⁺ to Sm²⁺. The different PL signatures of the two Sm-ions allow such materials to be used as x-ray dosimeters with optical readout. The X-ray induced luminescence (XL) spectra were also recorded. We discuss the experimental results in terms of established models for the behavior of rare-earths in glasses, crystalline solids and in nanocrystalline glass-ceramics.