Dopant concentration effect on the TL response of ZrO₂:Lu ³⁺ nanocrystals under β-ray irradiation

The thermoluminescence (TL) characterization of undoped and Lu³⁺ doped nanocrystalline ZrO₂ under β-ray irradiation is presented. The average crystallite size was 40 nm and the crystalline structure was monoclinic although for doped samples 5 wt% of tetragonal was observed. The TL results show a typical second order kinetic with four TL peaks centered around 120, 170, 240 and 280 °C when the sample is exposed to β-ray irradiation. The presence of dopant ion induces changes in the trapping process and recombination efficiency in the TL response. The result is that dominant peak typically centered at 120 °C was quenched while the peak centered at 240 °C was enhanced. This shifting to higher temperature of the dominant peak induces important changes in the dosimetric properties of nanocrystals. The dosimetric behavior for TL method and the TL fading of the samples under β-irradiation was systematically characterized as function of the dopant concentration. The high efficiency of the TL suggest a good potential of this nanophosphor as βirradiation dosimeter.