Radiophotoluminescence properties of Eu-doped Li₂SrSiO₄ for radiation detectors

To search for new radiophotoluminescence (RPL) materials, Eu-doped Li2SrSiO4 was synthesized by the solid-state reaction and then studied its RPL properties for radiation detector applications. All the samples were identified to be Li2SrSiO4 by X-ray diffraction. The as-prepared sample shows photoluminescence (PL) due to Eu3+ while an additional PL band appears due to a formation of Eu2+ after X-ray irradiation. This indicates that the Eu-doped Li2SrSiO4 has RPL properties. The sensitivity of RPL (or PL intensity of Eu2+) to X-ray dose is the highest when the Eu concentration is 0.1%, and the dynamic range is 5-10 000 mGy. In addition, the generated Eu2+ is so stable that only 5% of the signal degrades over 20 min after irradiation. The RPL signal notably decreases to about 30% of the initial value by heating at 500 degrees C for 100 s, and it is reproducible multiple times even after the heat treatment.