Europium doped alkali halide single crystals have been the subject of very intensive investigation due to its applications in digital medical radiography, optical memories and environmental dosimetry. The performance of these phosphorous materials exhibited in both thermoluminescence and optical stimulated luminescene, is generally explained through mechanisms where the photoionization of impurity is involved. However, no evidence of the presence of the Eu3+ ion has been reported yet. In this paper we present experimental insight into the defect creation processes generated by ionizing radiation, as well as ultraviolet light with energies below the band gap in both phenomena, which show the same 420 nm emission. The F and Fz centers are clearly related to the thermoluminescence glow curve. The results show a similar thermoluminescence and optical stimulated luminescence origin and may suggest the existence of a non-excitonic mechanism involved in the defect creation with ultraviolet non-ionizing radiation light.
|Number of pages
|Physica Status Solidi (B) Basic Research
|Published - Jul 2000