Thermoluminescence kinetics, time-dependent TL evolution and dosimetric performance of Tb3+-doped NaCa4(BO3)3: Effects of preheating and multi-trap structure.

ABSTRACT A series of Eu3+-activated Sr2CeVO6 phosphors with strong luminescence were successfully prepared via a solid-state reaction and were found to adopt a monoclinic crystal structure. Structural confirmation was obtained using Rietveld refinement of powder X-ray diffraction (XRD) patterns, while the average crystallite size was estimated using the Debye–Scherrer method. Upon excitation at 310 nm, the phosphors exhibited intense orange-red emission with high chromatic purity (91.43%), whereas excitation at 467 nm resulted in comparatively weaker red emission. The sample containing 3 mol-% Eu3+ showed maximum intensity, while further increase in dopant concentration led to a decrease in luminescence owing to concentration quenching. The thermoluminescence (TL) characteristics of the phosphors were evaluated following beta irradiation using a 90Sr/90Y source. A prominent glow peak was observed near 88°C along with a broad feature at elevated temperatures. The influence of dopant concentration, absorbed dose, and heating rate on TL response was systematically investigated. The TL output increased proportionally with beta dose, indicating good dose linearity. Trap parameters were computed using glow curve deconvolution, and the resulting analysis suggested that the peaks follow general-order kinetic. The variation of heating rate effects on glow peak intensity and position was analysed to assess thermal quenching behaviour.

X-ray-irradiated KCl:Eu2+ single crystal as a deformation-quantitative indicator sensitive to applied strain and load

KCl Single crystals doped with Eu2+ (0.03 mol% in melt) were compressively deformed at the cross-head speed of 50 µm min-1 until the dynamic recovery region of strain hardening. The crystals were irradiated with X-ray for various exposure times at room temperature. The optical absorption (OA) and the thermoluminescence (TL) glow were measured for the crystals. The absorption peak at the wavelength near 560 nm in the OA spectrum becomes larger rapidly with the increment of irradiation time until 30 min and then is saturated above approximately 50 min. The small absorption peak near 820 nm due to the M-centre tends to increase dependently on the X-ray irradiation time for times below 150 min. As for the TL glow curve, two peaks appear at about 370 and 450 K. Both the peak intensities grow until the irradiation time of 30 min and seem to be later saturated above 50 min. A peak also appears around 330 K on the TL glow curve for the crystals, but this peak is not observed in the case of irradiation alone for the same time without deformation. The peak intensity increases with the X-ray irradiation time up to 30 min. This is considered to be the reason why the number of F-centres lying in the expansion region of the dislocation segments increases with the irradiation of the KCl:Eu2+ crystals using X-ray. Thereafter, the intensity decreases slightly with increasing the irradiation time.

Chronology of accidental exposures based on differential thermoluminescence fading.

Radiation response of Er3+-doped SrF2 translucent ceramics

This work reports a photoluminescence (PL) and thermoluminescence (TL) glow curve study of Eu³+/Mn4+ dual-doped ZnAl2O4 phosphors prepared by the microwave combustion method. X-ray diffraction (XRD) and Rietveld refinement confirmed the formation of a phase-pure crystalline normal spinel structure (space group Fd3¯m), with no detectable secondary phases of Eu or Mn. Energy-dispersive X-ray spectroscopy (EDS) verified the successful incorporation of both dopants into the host lattice. Under UV (393 nm) excitation, the dual-doped phosphors exhibit sharp red emissions at 593 nm and 616 nm attributed to Eu³+ transitions. Under blue (462 nm) excitation, simultaneous sharp red (616 nm) emission from Eu³+ and broad far-red (705 nm) emission from Mn4+ are observed, yielding a broad red-emission profile across the visible range. The optimum composition (1/0.5 mol% Eu³+/Mn4+) achieved an external quantum efficiency of 55%. Time-resolved PL analysis revealed millisecond-scale decay lifetimes, attributed to carrier re-trapping from deep trap states. TL glow curve measurements under γ-irradiation (1–2.5 kGy) revealed broad glow peaks centered at approximately 399 K and 430 K. TL intensity increased up to 2 kGy and subsequently decreased at higher doses, this behavior is explained using the track interaction model. TL kinetic calculation by Chen’s method and computerized glow curve deconvolution method provides the information of activation energies and key trap parameters. The efficient broad red emission under blue excitation identifies Eu³+/Mn4+ dual-doped ZnAl2O4 as a promising red-emitting phosphor for plant-growth LED applications. Additionally, the TL glow curve response under γ-irradiation demonstrates its potential as a thermoluminescent dosimeter (TLD) material for radiation dosimetry.

A series of NaLi2PO4:Ce3+ phosphor was synthesized using a modified solid-state method. The structural and morphological characteristics were analyzed through XRD (X-ray diffraction) and SEM (Scanning Electronic Microscope). Identification of elemental composition of materials was completed through Energy Dispersive X-Ray Analysis (EDX). The PL excitation and emission spectra of prepared NaLi2PO4:Ce3+ were monitored at λEm = 358 and λEx = 312 nm respectively. OSL decay curve of the phosphor was deconvoluted in three exponential decay curves. The phosphor demonstrated superior OSL sensitivity, being 4.6 times more than α-Al2O3:C (BARC) phosphor, with minimum detectable dose (MDD) ∼14 µGy. The effective atomic number of NaLi2PO4:Ce3+ phosphor (Zeff = 10.8) is less than Zeff of α-Al2O3:C phosphor (Zeff = 11.28). The phosphor shows linear OSL dose response in the dose range of 0.6 mGy to 30 Gy and fading of the OSL signal was found to be about 40% in 1 day, stabilizing thereafter. The TL glow curve of NaLi2PO4:Ce3+ phosphor consists of overlapping peaks in the temperature range of 50°C to 400°C. The TL glow curve was deconvoluted, and the kinetic parameters, like life time, activation energy and frequency factor were evaluated by the TL glow curve deconvolution method. TL dose response is linear in the dose range of 0.6 mGy to 30 Gy and TL glow curve at various heating rate shows good thermal stability with negligible thermal quenching. The findings suggest that the synthesized phosphor is suitable for personal monitoring and environmental monitoring applications.

Enhanced thermoluminescence in scandium oxide via systematic annealing: effects on glow curve shape, reproducibility, and fading

Optimization of mode of heat treatment for thermoluminescence properties of beta irradiated synthetic quartz.

Thermoluminescence properties of Mexican calcite minerals for retrospective dosimetry.

This preliminary study investigates the synthesis and thermoluminescent properties of undoped and cerium (Ce 3+ )-doped CaAl 2 O 4 nanoparticles synthesized via solution combustion. Characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), derivative thermogravimetric (DTG), and differential scanning calorimetry (DSC), were employed to analyze the samples. The effects of ionizing radiation (beta particles and X-rays) were evaluated using thermoluminescence (TL) and radioluminescence (RL) techniques. The Ce 3+ -doped sample exhibited promising features such as high repeatability and reproducibility, a linear dose-response in range of 0.1 up to 3.0 Gy, and a low TL signal fading. By applying the T m -T stop and variable heating methods to analyze the glow curve, it was observed that high temperature peaks obey second-order kinetics with a frequency factor of 10 11 s −1 . These preliminary characteristics underscore its potential suitability for dosimetry applications.

Sample-to-Sample Variability and Glow Curve Behaviour of LiF:Mg, Ti for Radiotherapy Dosimetry Applications

This study investigates the thermoluminescence (TL) properties of natural obsidian samples collected from the Aksaray region in Turkey. The obsidian samples were ground into powder and sieved into five particle size ranges between 63 and 500 μm. The grain size range of 63-125 μm was identified as the most suitable for TL measurements, as it produced a sharper and more intense peak in the dosimetric region of the spectrum. Subsequently, detailed analyses were conducted on the TL glow curves, reusability, dose response, and heating rate behavior of the selected sample. The effect of heating rate was tested over a range of 0.1°C-10°C/s, revealing an anomalous heating rate dependence. Kinetic analysis using the method identified multiple peaks, indicating the presence of various energy levels. TL curve deconvolution using the general order kinetics model yielded activation energies ranging from 0.82 to 1.68 eV and demonstrated a strong correlation between the experimental data and theoretical predictions.

In this study, thermoluminescence analyses were performed on natural CaCO₃ mineral sample obtained from Konya region after exposure to beta irradiation. Examining the thermoluminescence curve of the un-annealed sample, it was determined that there is a maximum at 100 °C and a tail extension around 250 °C. To detect the presence of deep traps, annealing was performed at temperatures between 400-800°C. It was decided that the optimum annealing temperature was 700°C, with a duration of 60 minutes. The characteristics of dose sensitivity, linearity, and reusability were analyzed to identify the effective thermoluminescence (TL) maximum on the high-temperature side of the spectrum. The whole TL glow curve was investigated through the Tm-Tstop experiment. Tm-Tstop experiment analysis determined that the luminescence curve of the natural CaCO3 mineral sample is complex.

Thermoluminescent dosimetry properties of calcium oxide obtained from eggshells.

Analysis of dosimetric characteristics of CaSO4:Mn,Tb phosphors synthesized by four different routes.

This study focuses on the investigation of the TL behavior of the quartz sample that was collected from Khonglah, West Jaintia Hills District in Meghalaya. The sample was crushed into powdered sizes (10–100 µm) and heated to reset the trap structures prior to irradiation. Characterization techniques, such as XRD and EDS, were performed to analyze the structure and elemental composition of the prepared sample. The sample shows a trigonal structure with a hexagonal lattice arrangement. Intrinsic defects and impurity centers, such as Al, Mg, and Mn, were present in the sample. TL glow curve analysis was performed after gamma irradiation with different doses (10–70 Gy). With a gamma dose of 50 Gy, the sample showed a well-resolved glow curve with four intense peaks at 201°C, 238°C, 302°C and 350°C. Deconvolution of the peaks was done by using CGCD software and calculation of different trap parameters like the order of kinetics (b), activation energy (E), and the frequency factors (s) of the fitted glow curve was performed by Peak’s shape method. These results suggested that natural quartz from Meghalaya exhibits promising dosimetric characteristics due to its good TL response with gamma dose and can serve as a reliable and cost-effective material for personal and environmental radiation monitoring.

Study of Re3+ (Re3+= Er3+, Tm3+) impurity effects on thermoluminescence characteristic of magnesium sulfate nanorods.

Radiation detection using diatomite: A natural approach to gamma-ray dosimetry.