Thermoluminescence, optical stimulated luminescence and defect creation ineuropium doped KCl and KBr crystals

Europium doped alkali halide single crystals have been the subject of very intensive investigation due to its applications in digital medical radiogra phy, optical memories and environmental dosimetry. The performance of these phosphorous materials exhibited in both thermoluminescence and optical sti mulated luminescene, is generally explained through mechanisms where the ph otoionization of impurity is involved. However, no evidence of the presence of the Eu3+ ion has been reported yet. In this paper we present experiment al insight into the defect creation processes generated by ionizing radiati on, as well as ultraviolet light with energies below the band gap in both p henomena, which show the same 420 nm emission. The F and F-z centers are cl early related to the thermoluminescence glow curve. The results show a simi lar thermoluminescence and optical stimulated luminescence origin and may s uggest the existence of a non-excitonic mechanism involved in the defect cr eation with ultraviolet non-ionizing radiation light.