Positron lifetime study of the crystal evolution and defect formation processes in a scintillating glass

Abstract

<jats:p> <jats:bold>The crystal evolution and defect formation in scintillating glasses as a consequence of thermal annealing were studied by annihilation lifetime spectroscopy and UV‐Vis absorption spectroscopy. The annihilation lifetime spectra and UV‐Vis spectra were recorded on glass 50SiO<jats:sub>2</jats:sub>–45ZnO–5BaF<jats:sub>2</jats:sub> before and after annealing at 580°C for 16, 32, and 48 h, respectively. The results show that the three lifetime components (τ<jats:sub>1</jats:sub>, τ<jats:sub>2</jats:sub>, and τ<jats:sub>3</jats:sub>) and the corresponding intensities (<jats:italic>I</jats:italic><jats:sub>1</jats:sub>, <jats:italic>I</jats:italic><jats:sub>2</jats:sub>, and <jats:italic>I</jats:italic><jats:sub>3</jats:sub>) change systematically with increasing annealing time. This reflects the crystal evolution and defect formation in the glass matrix. The continued crystal evolution was also revealed by the UV‐Vis spectra, as the absorption edge of the material shifted to a lower energy with prolonged annealing.</jats:bold> </jats:p>