OSL and PTOSL of dosimetric materials: Observation of the luminescence after exposure to 90Sr+90Y source and LEDs in ultraviolet range

Abstract

The study of luminescence phenomena by crystal-based radiation detectors is suitable for radiation dosimetry, once the light emitted by them enables the quantification of their deposited radiation energy. The light emission can be promoted when a material is illuminated with a certain wavelength and time interval, as in the optically stimulated luminescence (OSL) and photo-transferred OSL (PTOSL) processes. The objective of this work is to evaluate the OSL and PTOSL responses of commercial dosimeters (LiF:Mg,Ti, CaF2:Dy, CaF2:Mn and CaSO4:Dy) in order to study their luminescence and the possibility of use in radiation dosimetry with the PTOSL technique. OSL and PTOSL responses of LiF:Mg,Ti, CaF2:Dy, CaF2:Mn and CaSO4:Dy dosimeters, commercially sold as TLD-100, TLD-200, TLD-400 e TLD-900, respectively, by Thermo Fischer Scientific, were studied. The samples were irradiated with the 90Sr+90Y source of the TL/OSL reader system Risø, and the measurements were taken using the same system and blue LEDs. For the PTOSL signal, the dosimeters were irradiated, thermally treated and illuminated with LEDs with wavelengths between 265 nm and 420 nm. The most intense OSL signal occurred for TLD-100. Comparing the OSL and PTOSL results, it is possible to observe clearly the photo-transferred effect for TLD-100. For TLD-200 and TLD-400, no effects were noted. In the case of TLD-900, it presented a PTOSL signal in a small-scale when analyzing the curve integral.