Radiophotoluminescence in Ag-doped KBr for dosimetry applications

The non-doped and Ag-doped KBr transparent ceramics were fabricated by the spark plasma sintering (SPS), and their radiophotoluminescence (RPL) properties were investigated. Following X-ray exposure, the Ag-doped samples exhibited new photoluminescence (PL) emission bands in the blue and orange spectral regions, centered at around 450 and 580 nm. These emissions were most effectively excited at 315 and 340 nm. The emission around 450 nm is tentatively assigned to Ag⁰/Ag₂⁺ based on previous reports, whereas the orange emission near 580 nm would be attributed to Ag²⁺, as supported by the measured PL decay time and previous reports. Furthermore, the 580 nm emission exhibited a build-up effect after X-ray irradiation, suggesting that the readout timing may influence the measured RPL intensity. The highest sensitivity was obtained for the 0.5% Ag-doped sample, with detectable RPL signals from 10 mGy and a nearly proportional dose response over the range of 10-3000 mGy. The Ag-doped KBr transparent ceramic exhibited lower detection sensitivity with a minimum detectable dose of 10 mGy, compared with commercial Ag-doped phosphate glass dosimeters (0.1 mGy) and Ag-doped CsBr transparent ceramics (3 mGy). The present results establish the fundamental RPL characteristics of Ag-doped KBr transparent ceramics and provide a basis for the further development of KBr-based transparent ceramic RPL dosimeters.