Optical properties of Mn2+ doped CsCdF3: A potential real-time and retrospective UV and X-ray dosimeter material

Abstract

Luminescence measurements of CsCdF3:Mn reveal material properties suitable for UV and X-ray sensing. Mn2+ substitutes for Cd2+ with octahedral crystal field parameters 10Dq = 7020 ± 120 cm−1 and B = 773 ± 13 cm−1. UV stimulation at 250 nm results in intense Mn2+ emission and also in the production of F-centers and additional defects. Continuous 250 nm stimulation charges the material, enhancing the Mn2+ emission intensity over time due to the filling of shallow traps that contribute to persistent luminescence. When the stimulation is ceased, Mn2+ emission is observed as an afterglow. F-centers give rise to optically stimulated luminescence (OSL) that is temporally stable and can be stimulated at wavelengths near 300 nm. We propose a model that describes these effects, where UV stimulation results in electron transfer from Mn2+ to the conduction band and subsequent electron trapping in various defect states. X-ray stimulation produces Mn2+ radioluminescence that varies in intensity by 0.004%/Gy after a 300 Gy priming dose. The X-ray irradiation also produces OSL-active F-centers and the defects that cause the afterglow. Thermoluminescence measurements reveal low-temperature peaks that are correlated with the afterglow and high-temperature peaks that are correlated with the OSL, after both X-ray and UV irradiations. The luminescence of Mn2+ in CsCdF3:Mn may be useful for radiation sensing, where the real-time changes in Mn2+ emission under X-ray and UV stimulation allow for real-time dose measurements, and the OSL induced by each irradiation allows for retrospective dose monitoring.