Thermoluminescence response of rare earth activated zinc lithium borate glass

Anomalous dose behaviour of thermoluminescence glow curves and kinetic analysis of beta irradiated YAl3(BO3)4:Tb phosphor

With the aid of thermoluminescence (TL), we have extensively studied YAl₃(BO₃)₄ host matrices incorporated with Tb³⁺ at different doping contents, which have been produced by combustion. The measured the TL glow curves exposed to beta rays at different doses consisted of four broad peaks located at around 76, 126, 230, and 378 °C. The peak maximum of the 230 °C TL peak shifts toward higher temperatures after 5 Gy beta irradiation while the other peak maxima almost remain constant. It is peculiar that 230 °C peak maximum shifts to higher temperatures with increased radiation dose and can be attributed to the multiple phases of the sample. A TL glow curve exhibits a proportional increase in intensity with increased the heating rate. A discussion of the possible causes of this pattern is provided. Observed peaks using the T_m─T_stop method are due to the presence of a quasi-continuous distribution of traps. The parameters of the traps have also been estimated using various heating rate methods in excellent agreement with one another.

Luminescence properties of Ce-doped ZrO2 phosphors synthesized by combustion method

Zr_1-x Ce_x O₂ with x = 0.005, 0.01, 0.02, and 0.03 samples were synthesized using a combustion technique. The X-ray diffraction results revealed that Ce-doped ZrO₂ nanoparticles were in a monoclinic structure up to 1 mol% Ce concentration. The increase in the Ce concentration caused more distortion in the monoclinic structure of zirconia. The samples showed a mixed phase (monoclinic + tetragonal) beyond 1 mol% Ce content. The crystallite size (D) and strain (ε) were calculated from the Williamson-Hall equation. The D decreased from 25 ± 1 to 20 ± 1 nm and ε increased from 0.03 to 0.28% with an increase in Ce concentration. Photoluminescence (PL) spectra of Zr_1-x Ce_x O₂ showed emission in the blue region under an excitation wavelength of 290 nm. Zr_0.995 Ce_0.005 O₂ showed the highest PL intensity with an average lifetime of 0.93 μs, and the PL intensity decreased with the increase in the Ce concentration. Thermoluminescence (TL) glow curves of Zr_1-x Ce_x O₂ were measured after gamma irradiation (500 Gy) with a heating rate of 5 K s^-1 . The TL curve of Zr_0.995 Ce_0.005 O₂ showed two prominent peaks at 412 K (peak 1) and 600 K (peak 2). The first TL glow peak was shifted towards a higher temperature at 440 K above 1 mol% Ce concentration. Repetitive TL measurements on the same aliquot exhibited excellent repeatability. Kinetic parameters associated with the TL peaks were calculated using the curve fitting method. Peak 1 followed non-first-order kinetics. The value of the activation energy of the 440 K peak was found to be 0.95 ± 0.01 eV for Zr_0.99 Ce_0.01 O₂ . These findings showed that Zr_1-x Ce_x O₂ might be used in lighting and radiation dosimeter applications.

Development of Ag-Doped ZnO Thin Films and Thermoluminescence (TLD) Characteristics for Radiation Technology

This work examined the thermoluminescence dosimetry characteristics of Ag-doped ZnO thin films. The hydrothermal method was employed to synthesize Ag-doped ZnO thin films with variant molarity of Ag (0, 0.5, 1.0, 3.0, and 5.0 mol%). The structure, morphology, and optical characteristics were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), photoluminescence (PL), and UV-vis spectrophotometers. The thermoluminescence characteristics were examined by exposing the samples to X-ray radiation. It was obtained that the highest TL intensity for Ag-doped ZnO thin films appeared to correspond to 0.5 mol% of Ag, when the films were exposed to X-ray radiation. The results further showed that the glow curve has a single peak at 240-325 °C, with its maximum at 270 °C, which corresponded to the heating rate of 5 °C/s. The results of the annealing procedures showed the best TL response was found at 400 °C and 30 min. The dose-response revealed a good linear up to 4 Gy. The proposed sensitivity was 1.8 times higher than the TLD 100 chips. The thermal fading was recorded at 8% for 1 Gy and 20% for 4 Gy in the first hour. After 45 days of irradiation, the signal loss was recorded at 32% and 40% for the cases of 1 Gy and 4 Gy, respectively. The obtained optical fading results confirmed that all samples' stored signals were affected by the exposure to sunlight, which decreased up to 70% after 6 h. This new dosimeter exhibits good properties for radiation measurement, given its overgrowth (in terms of the glow curve) within 30 s (similar to the TLD 100 case), simple annealing procedure, and high sensitivity (two times that of the TLD 100).

Ceramics, Glass and Glass-Ceramics for Personal Radiation Detectors

Different types of ceramics and glass have been extensively investigated due to their application in brachytherapy, radiotherapy, nuclear medicine diagnosis, radioisotope power systems, radiation processing of food, geological and archaeological dating methods. This review collects the newest experimental results on the thermoluminescent (TL) properties of crystalline and glassy materials. The comparison of the physico-chemical properties shows that glassy materials could be a promising alternative for dosimetry purposes. Furthermore, the controlled process of crystallization can enhance the thermoluminescent properties of glasses. On the other hand, the article presents information on the ranges of the linear response to the dose of ionizing radiation and on the temperature positions of the thermoluminescent peaks depending on the doping concentration with rare-earth elements for crystalline and glassy materials. Additionally, the stability of dosimetric information storage (fading) and the optimal concentration of admixtures that cause the highest thermoluminescent response for a given type of the material are characterized. The influence of modifiers addition, i.e., rare-earth elements on the spectral properties of borate and phosphate glasses is described.

Thermoluminescence characteristics of lithium borosilicate glass doped with Sm2 O3

Lithium borosilicate glass composite (SiO₂ -Li₂ CO₃ -H₃ BO₃ ) doped with various concentrations of Sm₂ O₃ (0-0.7 mole %) was prepared using the melt quenching method. The investigated thermoluminescence (TL) characteristics of the prepared system revealed that the highest TL response was obtained for this glass composite at 0.05 mol% Sm₂ O₃ . In this study, the 0.05 mol% Sm₂ O₃ -doped lithium borosilicate glass composite was subjected to detailed dosimetric investigation in terms of its annealing condition, dose-response, and minimum detectable dose. The reproducibility of the response, thermal characteristics, and optical fading were also studied. The obtained results showed that the prepared glass composite had a linear dose-response over the wide gamma dose range 2Gy to 2 kGy, as well as reasonable thermal fading and excellent reproducibility. These attributes render the composite under investigation promising for utilization in radiation detection.

Thermoluminescence emission on lead oxychloroborate glasses under UV exposure

Glassy materials were prepared using two different systems: 50B₂ O₃ - (50 - x)PbO - xPbCl_2, with x = 0, 2 and 5 in mol % (System BPCl-I) and 50BO_1.5 - (50 - x)PbO - xPbCl₂ with x = 0, 2, 5 and 7 in cationic % (System BPCl-II). Structural and optical characterization showed that PbCl when substituted for PbO changed the structure of the glass network by replacing nonbridging oxygens for chlorine ions. This substitution also caused a change in the number of defects responsible for thermoluminescence (TL) emission (electrons and hole trap centres). Thermoluminescence emissions were observed for the first time in lead oxychloroborate glasses after exposure to UV radiation. Sample BPCl-I-2 (x = 2 from System I) demonstrated better TL emission compared with other glass samples. One intense peak in the glow curve, centred at ~122°C followed by a shoulder at ~180°C, was highly sensitive to UV radiation. There were also good linear responses at dose range ~0.4 to ~2 J/cm² for the first peak (low temperature) and ~0.4 to ~4 J/cm² for the second peak (high temperature).

Synthesis and luminescence characterization of microcrystalline Nd-doped calcium sulfate

In the present study, the precipitation method was used to synthesize microcrystalline Nd-doped CaSO₄ phosphor. Structural and morphological analysis of the phosphor samples were performed by using X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. In addition, luminescent properties of the samples were characterized by thermoluminescence (TL) and optically stimulated luminescence (OSL) methods. The results of XRD analysis and SEM images showed that the prepared CaSO₄:Nd powder samples have an orthorhombic crystal structure and almost spherical in size with an average between 3 and 17 μm. In the light of the luminescence analysis, the optimum preheat temperature required to evacuate the low temperature electron traps was determined as 170 °C. It was also presented that CaSO₄:Nd samples have the potential to be used as a dosimetric material with a linear dose sensitivity between 1 and 20 Gy (as TL dosimeter), and 1 and 10 Gy (as an OSL dosimeter) when they are exposed to beta irradiation. In addition, the full width at the half maximum (FWHM) values of the main TL peaks presented no independence of HR.