Persistent luminescence dosimetric properties of UV-irradiated SrAl2O4 : Eu2+, Dy3+ phosphor

Current radiation dosimetry methods involve the release of trapped charge carriers in the form of electrons-holes pairs generated by irradiation exposure of the dosimetric materials. Thermal and optical stimulations of the irradiated material freed the trapped charges that eventually recombine with interband centers producing the emission of light. The integrated intensity of the emitted light is proportional to the radiation dose exposure. In this work, we present an UV radiation dosimetry technique based on the characteristic persistence luminescence (PLUM) 4f(6)5d(1) -> 4f(7) electronic transition of Eu2+ ions in SrAl2O4:EU2+, Dy3+. The dose assessment is carried out by measuring the PLUM signal integrated during a certain time. The PLUM performance of SrAl2O4:Eu2+, Dy3+ phosphor exhibited a linear behavior for the first 50 s of UV irradiation. For higher UV time exposure the behavior is sublinear with no apparent saturation during a 10 min period. The PLUM dosimetry response was performed at 400 nm that corresponds to the main band component of the PLUM excitation spectrum in the 250-500 nm range. The main advantage of a dosimeter device based on the PLUM of SrAl2O4:Eu2+, Dy3+ is that neither thermal nor optical stimulation is required, avoiding the need of cumbersome electronic photo/ thermal stimulation equipment. Due to the highly efficient 250-500 nm PLUM response of SrAl2O4:EU2+, Dy3+, it could have potential application as UV radiation dosimeter in the UV range of grate human health concerns caused by UV solar radiation. (C) 2007 Elsevier B.V. Ail rights reserved.