V. R. Orante-Barrón

Thermoluminescence of novel zinc oxide nanophosphors obtained by glycine-based solution combustion synthesis

High-dose thermoluminescence dosimetry properties of novel zinc oxide nanophosphors synthesized by a solution combustion method in a glycine-nitrate process are presented for the very first time in this work. Sintered particles with sizes ranging between ∼500 nm and ∼2 µm were obtained by annealing the synthesized ZnO at 900°C during 2 h in air. X-ray diffraction patterns indicate the presence of the ZnO hexagonal phase, without any remaining nitrate peaks observed. Thermoluminescence glow curves of ZnO obtained after being exposed to beta radiation consists of two maxima: one located at ∼149°C and another at ∼308°C, the latter being the dosimetric component of the curve. The integrated TL fading displays an asymptotic behavior for times longer than 16 h between irradiation and the corresponding TL readout, as well as a linear behaviour of the dose response without saturation in the studied dose interval (from 12.5 up to 400 Gy). Such features place synthesized ZnO as a promising material for high-dose radiation dosimetry applications.

Synthesis and Thermoluminescence of New ZnO Phosphors

In this work, the synthesis and thermoluminescence properties of new ZnO phosphors obtained by a chemical method are reported. Some samples were exposed to beta particle irradiation for doses ranging from 10.0 up to 6,400 Gy, and it was found that the thermoluminescence response as a function of dose is linear for doses below 200 Gy, and sublinear with no saturation clouds for greater doses. A broad shape glow curve with maximum located above 230 °C, that shifts to lower temperatures as dose increases, indicating that second order kinetics thermoluminescence processes are involved. The lower detection limit was estimated to be 13 Gy. We conclude that the phosphors under study are promising to develop dosimeters for high dose radiation dosimetry.

Synthesis and Thermoluminescent Properties of New ZnO Phosphors

In this work, results on the thermoluminescence dosimetry properties of beta particle irradiated ZnO obtained by thermal annealing of chemically synthesized ZnS are reported. ZnS powder was sintered at 950 °C during 24 h in air, in order to obtain pellet-shaped ZnO samples. The thermoluminiescence (TL) intensity of ZnO previously exposed to beta radiation increased as the dose increased in the 0.025-6.4 kGy interval studied. Characteristic glow curves exhibited two emission maxima at ~ 94 and ~ 341 °C. The dosimetric peak located at ~ 341 °C shifted towards lower temperatures as the dose increased, which indicates that second-order kinetic processes are involved in the thermoluminiescence emission. The dose response of ZnO showed a linear behaviour in the 0.025 Gy-0.8 kGy dose interval, which makes this material suitable and promising for medical, industrial and also space dosimetry applications. The thermoluminescence total signal faded down 48 % 6 h after irradiation and showed an asymptotic behaviour for longer times, due mainly to the ~ 341 °C stable and dosimetric glow peak.

Thermoluminescence of Beta Particle Irradiated LiMgF 3 :X (X=Ce, Er)

The thermoluminescence (TL) properties of beta particle irradiated Ce and Er doped LiMgF 3 phosphors are presented. Pellet-shaped samples were prepared by cool-pressing 74 μm size particle powder, followed by thermal annealing at 700 °C during 5 h in air atmosphere. Some samples were irradiated with beta particles in the dose range from 8 up to 128 Gy. The sensitivity of Er doped samples was greater than the one of Ce-doped. In both cases, a 2 % mol of dopant concentration was used. The TL fading was between 19 % for Ce-doped samples, and 24 % for the Er-doped. The integrated TL increases as dose increases, with no saturation clues. The TL sensitivity of samples exhibited a loss in successive irradiation – readout cycles.