RPL properties of samarium-doped CaSO4

Radiophotoluminescence (RPL) properties of Sm-doped CaSO4 for radiation dosimetry applications are reported. The samples with varying Sm concentrations are prepared via the solid-state reaction process. The as-prepared samples show photoluminescence due to typical 4f–f transitions of Sm3+ whereas, after X-ray irradiation, additional emission features appear with a broad band peaking at 630 nm as well as a set of multiple sharp lines across 680–820 nm, which are attributed to the 5d–4f and 4f–4f transitions of Sm2+, respectively. Therefore, the RPL in the present material system relies on the generation of Sm2+ centers. The sensitivity is about 3 times lower than that of Ag-doped phosphate glass, but no fading and build-up of signal are evident even immediately after the irradiation. The signal is reversible by heat-treatment at 500 °C, and is reproducible even after the thermal erasure, especially when the differential signal between pre- and post-irradiation is taken into account.