33 research outputs found
Thermoluminescence spectra of Tm doped ZnB2O4 phosphor prepared via a wet-chemical synthesis
No full textIn this paper we describe the thermoluminescence (TL) characteristics of 0.8 mol% Tm3+ doped ZnB2O4 phosphors prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of three peaks located at 181 degrees C, 213 degrees C and 351 degrees C. The glow peak TL temperature (T-m) at which the TL glow peak occurs shifts toward the higher temperature side whilst the heating ramp rate increases and also the peak TL intensity (I-m) decreases. The TL glow curves are characterized by evaluating various dosimetric characteristics of scrutinized samples. The T-m - T-stop investigations on regenerated TL signals revealed that there are five different traps in the phosphor with energy values in the range of 0.61-1.71 eV. The dose responses increased in a linear way for 3 peaks with the beta-ray exposure in the dose range of 0.11-60 Gy. The process of applying 10 Gy dose was repeated for ten successive irradiation cycles to check reproducibility and the maximum variation was found to be less than 1% from the average value. These results provide valuable knowledge for use of the characteristics of T-m doped ZnB2O4 in dosimetry research.Çukurova Üniversitesi (FAY- 2015-4735, FDK- 2017-7905
Thermoluminescence spectra of Tm doped ZnB2O4 phosphor prepared via a wet-chemical synthesis
No full textWOS: 000470046200026PubMed ID: 30878780In this paper we describe the thermoluminescence (TL) characteristics of 0.8 mol% Tm3+ doped ZnB2O4 phosphors prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of three peaks located at 181 degrees C, 213 degrees C and 351 degrees C. The glow peak TL temperature (T-m) at which the TL glow peak occurs shifts toward the higher temperature side whilst the heating ramp rate increases and also the peak TL intensity (I-m) decreases. The TL glow curves are characterized by evaluating various dosimetric characteristics of scrutinized samples. The T-m - T-stop investigations on regenerated TL signals revealed that there are five different traps in the phosphor with energy values in the range of 0.61-1.71 eV. The dose responses increased in a linear way for 3 peaks with the beta-ray exposure in the dose range of 0.11-60 Gy. The process of applying 10 Gy dose was repeated for ten successive irradiation cycles to check reproducibility and the maximum variation was found to be less than 1% from the average value. These results provide valuable knowledge for use of the characteristics of T-m doped ZnB2O4 in dosimetry research.Scientific Research Projects of Cukurova University-Turkey [FDK-2017-7905, FAY-2015-4735]The authors are grateful for the financial support from the Scientific Research Projects of Cukurova University-Turkey, FDK-2017-7905 and FAY-2015-4735 projects. Besides, authors would like to thank Dr. Tamer Dogan and Dr. Mehmet Yuksel for their contributions to this study
Thermoluminescence spectra of Tm doped ZnB 2 O 4 phosphor prepared via a wet-chemical synthesis
No full textPubMedID: 30878780In this paper we describe the thermoluminescence (TL) characteristics of 0.8 mol% Tm 3+ doped ZnB 2 O 4 phosphors prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of three peaks located at 181 °C, 213 °C and 351 °C. The glow peak TL temperature (T m ) at which the TL glow peak occurs shifts toward the higher temperature side whilst the heating ramp rate increases and also the peak TL intensity (I m ) decreases. The TL glow curves are characterized by evaluating various dosimetric characteristics of scrutinized samples. The T m -T stop investigations on regenerated TL signals revealed that there are five different traps in the phosphor with energy values in the range of 0.61–1.71 eV. The dose responses increased in a linear way for 3 peaks with the beta-ray exposure in the dose range of 0.11–60 Gy. The process of applying 10 Gy dose was repeated for ten successive irradiation cycles to check reproducibility and the maximum variation was found to be less than 1% from the average value. These results provide valuable knowledge for use of the characteristics of T m doped ZnB 2 O 4 in dosimetry research. © 2019 Elsevier LtdFAY- 2015-4735, FDK- 2017-7905The authors are grateful for the financial support from the Scientific Research Projects of Cukurova University-Turkey, FDK- 2017-7905 and FAY- 2015-4735 projects. Besides, authors would like to thank Dr. Tamer Dogan and Dr. Mehmet Yüksel for their contributions to this study
Undoped and Eu doped LaCa₄O(BO₃)₃ phosphors: Thermoluminescence characteristics with a focus on kinetic parameters, anomalous heating rate, and dose response
No full textThe thermoluminescence (TL) properties of LaCa₄O(BO₃)₃ (LACOB) phosphors, both undoped and doped with 0.5 % Eu³⁺, were synthesized using a microwave-assisted sol-gel method and analysed under beta irradiation doses ranging from 0.1 Gy to 700 Gy. The TL glow curves revealed prominent peaks at 100 °C and 285 °C for the Eu-doped sample. Activation energy values were calculated using the Hoogenstraaten and Booth-Bohun-Parfianovitch methods, yielding 1.52 eV and 1.48 eV for the undoped sample, and 2.07 eV and 2.01 eV for the Eu-doped sample, respectively. Eu³⁺ ions introduced deeper traps and enhanced the thermal stability of the material. Anomalous increases in TL intensity with rising heating rates were observed, deviating from typical thermal quenching behaviour; this phenomenon was explained using a semi-localized transition (SLT) model. The TL reusability measurements demonstrated a standard deviation of less than 5 %, indicating consistent and reliable performance across multiple cycles. The TL glow curve deconvolution identified six distinct peaks in the undoped sample, while the Eu-doped sample showed a more complex trap structure with eight peaks, indicating the introduction of additional or modified trapping sites by Eu doping. The figure of merit (FOM) values obtained from the deconvolution analysis were all below 2.5 %, indicating a good fit between the observed and fitted TL signals. These findings suggest that Eu³⁺-doped LACOB is a robust material for radiation dosimetry, with its enhanced sensitivity, stability, and versatility across various dosimetric applications. © 2024 Elsevier Ltd and Techna Group S.r.l.Deanship of Graduate Studies and Scientific ResearchJazan University, (RG24-M04)Jazan Universit
Thermoluminescence glow curve analysis and evaluation of trapping parameters of dysprosium doped lanthanum calcium borate La2CaB10O19
No full textThe present work elucidates thermoluminescence study of Dy activated lanthanum calcium borate (La2CaB10O19) phosphors and determination of trapping parameters. Two glow curves located at 132 and 295 °C were observed and showed a linear TL response. The kinetic parameters of the glow peaks were evaluated using variable heating rate, repeated initial rise method and Computerized Glow Curve Deconvolution. Analysis of the main dosimetric peaks reveals that the values of the activation energy and pre-exponential factor are found to be 0.78–1.145 eV and 8.59 × 109–8.44 × 1011 s−1, respectively. The sample doped with 1% Dy3+ exhibits a good stability for the reusability. Besides, the found results indicate that the temperature maximum shifts to the higher temperature side as the heating rate increases. Contrary to previously expressed theoretical expectations, anomalous heating rate dependence was observed in Dy3+ doped La2CaB10O19 sample and a semi-localized transition model explaining the anomalous heating rate effect was employed. © 2020 Elsevier B.V
Thermoluminescence glow curve analysis and evaluation of trapping parameters of dysprosium doped lanthanum calcium borate La2CaB10O19
No full textThe present work elucidates thermoluminescence study of Dy activated lanthanum calcium borate (La2CaB10O19) phosphors and determination of trapping parameters. Two glow curves located at 132 and 295 degrees C were observed and showed a linear TL response. The kinetic parameters of the glow peaks were evaluated using variable heating rate, repeated initial rise method and Computerized Glow Curve Deconvolution. Analysis of the main dosimetric peaks reveals that the values of the activation energy and pre-exponential factor are found to be 0.78-1.145 eV and 8.59 x 10(9)-8.44 x 10(11) s(-1), respectively. The sample doped with 1% Dy3+ exhibits a good stability for the reusability. Besides, the found results indicate that the temperature maximum shifts to the higher temperature side as the heating rate increases. Contrary to previously expressed theoretical expectations, anomalous heating rate dependence was observed in Dy3+ doped La2CaB10O19 sample and a semi-localized transition model explaining the anomalous heating rate effect was employed
Kinetic parameters and anomalies in heating rate effects of the thermoluminescence from rock salt from Tuzluca in Turkey
No full textIn this work, thermoluminescence (TL) characteristics and kinetic parameters of naturally occurring rock salts were presented. The samples were crushed and compressed into pellets before being irradiated with beta radiation doses ranging between 0.1 Gy and 15 Gy. TL responses exhibited four peaks at about 95 degrees C, 182 degrees C, 265 degrees C, and 360 degrees C in the glow curve. By increasing the heating rates, we observed an increase in the peak maximum temperature and the area of each peak as well as in the full width half maximum (FWHM), which shows an anomalous heating-rate effect. Taking a rock salt sample, the standard deviation was less than 1%, which was a good indication of repeatability. Using the initial rise (IR) and variable heating rate (VHR) approaches, the trapping parameters were calculated. The findings suggest that salt samples from the Tuzluca district in Turkey may be useful as radiation dosimeters
Comparison of thermoluminescence characteristics of undoped and europium doped YAl3(BO3)(4) phosphor synthesized by combustion method: Anomalous heating rate, dose response and kinetic analyses
No full textIn this study, undoped and YAl3(BO3)(4) phosphors doped with Eu3+ at varying concentrations (x = 0.5 to 7 wt%) produced by a combustion process have been thoroughly examined by using the X-ray diffraction (XRD) and thermoluminescence (TL) techniques. The crystallized phosphors were confirmed by XRD analysis, and its crystal structure was examined. XRD analyses of the synthesized phosphor is in accordance with ICSD File No 96-152-6006. TL glow curve of undoped sample produced three glow peaks located at 80 degrees C, 240 degrees C, and 360 degrees C with a heating rate of 2 degrees Cs-1 whilst Eu3+ doped one appears at 90 degrees C, 230 degrees C, and 390 degrees C. The undoped example complied with the theory as expected, namely, as the heating rate increased, the TL glow curve shifted towards lower temperatures and decreased in intensity. However, an anomalous change was observed in the sample with Eu3+ additive. The experimental findings from the dose-response of YAl3(BO3)(4):0.5 wt%Eu3+ demonstrate that the intensity of TL provided by the total area under glow curves has an acceptable linearity (r(2):0.999) up to 100 Gy. The intensity of each maximum on the TL glow curve augments proportionally as the heating rate is augmented. Possible reasons of this behaviour are discussed. Various heating rate (VHR) methods (such as Hoogenstraaten's and Booth-Bohun-Parfianovitch) have also been used to estimate kinetic parameters (e.g., energy and frequency factor), which seem to be in good agreement with each other
Thermoluminescence response and kinetic parameters of Tb-doped GdCa4O(BO3)3 under beta irradiation
No full textIn this study, the thermoluminescence (TL) properties of Tb3+-doped GdCa4O(BO3)3 (GdCOB) are investigated with focus on the effects of optical filter selection, preheating, dopant concentration, irradiation dose, heating rate on these properties. Trapping parameters of the traps responsible for the peaks in the phosphor were also determined. The IRSL-TL-565 nm filter was identified as optimal filter for isolating the characteristic green emission of Tb3+ and improving the signal-to-noise ratio. Among the studied dopant concentrations (1, 2, 3, 5, and 7 wt%), 3 wt% Tb3+ was found to maximize TL intensity. Beyond this concentration, quenching effects became dominant, leading to reduced TL efficiency. At 3 wt% doping, TL glow peaks were observed at approximately 80 and 190 °C following a 50 Gy beta dose with a heating rate of 2 °C/s, with the primary peak (∼190 °C) favorable for minimizing thermal fading. The TL response of the primary peak was linear with dose within 5–500 Gy. The peak's TL intensity is affected by thermal quenching effects. Reusing of an aliquot of the phosphor ten times produced responses with 0.45 % maximum deviation from their mean. Additionally, the peak temperature (Tm) exhibited a slight decrease beyond 100 Gy, which can be attributed to charge carrier interactions, trap filling effects, and potential thermal quenching at higher doses. Heating rate experiments showed the expected shift of peak temperatures to higher values, emphasizing the need to correct for temperature lag in kinetic analyses. Computerized glow curve deconvolution (CGCD) indicated the presence of at least eight distinct trapping levels with activation energies ranging from 0.90 to 1.69 eV, revealing a complex trap structure. Overall, with its high TL intensity, linear dose response, and aliquot reusability, Tb3+-doped GdCOB is a promising phosphor for personal dosimetry, environmental radiation monitoring, and medical imaging. © 2025 Elsevier Lt
Thermoluminescence behavior of Sm3+ activated ZnB2O4 phosphors synthesized using low temperature chemical synthesis method
No full textThis study is mainly centered on thermoluminescence (TL) behavior under beta excitation at room temperature (RT) of Sm3+ activated ZnB2O4 phosphors synthesized by low temperature chemical synthesis method. The prepared phosphors were characterized by the X-ray powder diffraction (XRD) method. The effects of dopant concentration, beta radiation dose (0.115–69 Gy) and heating rate (0.5–10 °C/s) on TL intensity of Sm3+ doped ZnB2O4 phosphors and reproducibility are investigated using a lexsyg smart TL/OSL reader system. The activation energy values, E obtained from the analysis of the TL glow curve were calculated with initial rise (IR) method and peak shape (PS) method over the deconvoluted glow curves. The Ea–Tstop and CGCD methods indicated that the glow curve of this phosphor is the superposition of at least six components, which were called to as P1–P6, in the temperature range between RT and 400 °C. The results reveal that 2% Sm3+ doped ZnB2O4 gives optimum TL response, the relative intensity of the glow peak increases linearly with increase of beta dose and, the peaks of TL glow curves shift towards the higher temperature side with increase in heating rate as the total area under the glow peak remains the same. The maximum variation of reproducibility for ten successive irradiation cycles of 20.7 Gy is less than 3% from the average value and the sample doped 2% Sm3+ shows a good stability for the reusability. Additionally, the results obtained from IR and PS methods indicates that the complex glow curve is composed of six distinguishable peaks. © 2018 Elsevier B.V
