APPLIED RADIATION AND ISOTOPES

In 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

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

This 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 degrees 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 E-a-T-stop 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 degrees 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

Cathodoluminescence properties of La2MoO6:Ln3+ (Ln: Eu, Dy, and Sm) phosphors

La2MoO6 orange-red phosphors with high efficiency incorporated with Eu, Dy and Sm have been synthesized through a gel combustion method. The influences of rare earth doping in synthesized samples were analysed by X-ray diffraction (XRD), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), and cathodoluminescence. Rare earth doped La2MoO6 samples show strong emission bands in the range of 400–750 nm and optimal doping concentration for all samples was 2 mol%. La2MoO6 host doped Eu ion showed intense and predominant emission peaks in 450–750 nm range. The electrical multipolar interaction contributed to the non-radiative energy transfer between Eu3+ ions in La2MoO6 host matrix. Sm doped La2MoO6 host exhibited orange-red CL emission peaks at 564, 608, 652 and 708 nm La2MoO6:Dy3+ phosphor displayed emissions at 484, 574 and 670 nm, respectively. The observed intense and sharp emission peaks indicate that La2MoO6 is promising host for lanthanides doped phosphor materials in the applications of optoelectronic. © 2020 Elsevier Lt

Thermoluminescence spectra of Tm doped ZnB 2 O 4 phosphor prepared via a wet-chemical synthesis

PubMedID: 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

Thermoluminescence spectra of Tm doped ZnB2O4 phosphor prepared via a wet-chemical synthesis

WOS: 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 behavior of Sm3+ activated ZnB2O4 phosphors synthesized using low temperature chemical synthesis method

This 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

Effects of Mn and Gd Co-substituted into ZnO on Structural and Magnetic Properties

We have worked on the structural and magnetic properties of Zn0.99-xMn0.01GdxO?(for x = 0.02, 0.03, and 0.04) compounds prepared by using a sol–gel method. The x-ray diffraction, scanning electron microscopy, and energy dispersive x-ray spectroscopy were used to understand the structural properties of the samples. We observed that co-substitution of Mn (1 %) and Gd (2–4 %) into the ZnO does not change the hexagonal structure. Scanning electron microscope (SEM) images show us that the grain size decreases with the increasing amount of the Gd into the ZnO matrix. The magnetic properties of the samples have been investigated by using magnetic hysteresis and DC susceptibility measurements. The ZMG1 sample shows a weak ferromagnetic behavior at room temperature, whereas the ZMG2 and ZMG3 samples exhibit a paramagnetic nature. Furthermore, it is also found that the magnetizations of the samples decrease with increasing Gd content in the ZnMnO system due to the enhancing interaction between Gd 3+ ions. We summarize that the co-substitution of Mn and Gd into the ZnO generates a room-temperature ferromagnetism, but it still needs more work to obtain strong and high coercivity magnetic loops for applications. © 2014, Springer Science+Business Media New York

Doping Sm3+ into ZnB2O4 phosphors and their structural and cathodoluminescence properties

In this study, ZnB2O4:xSm3+ (0.01 ? x ? 0.05 mol) powder phosphors have been synthesized by low temperature chemical synthesis method. The structure and morphological observation of the phosphor samples were systematically monitored by X-ray powder diffraction (XRD) and environmental scanning electron microscope (ESEM) coupled to an energy dispersive X-ray spectrometer (EDS). The all diffraction peaks are well assigned to standard data card (PDF#39-1126). Emission properties of the samples were explored using light emission induced by an electron beam (i.e cathodoluminescence, CL) at room temperature (RT). When excited with electron beam, CL spectral measurements of scrutinized phosphors exhibit orange-red luminescence at 572 nm, 606 nm and 658 nm due to various transition from ground state to 6H5/2,6H7/2 and 4G5/2 states, respectively. The transition 4G5/2 › 6H7/2 located at 606 nm can occur as hypersensitive transition having the selection rule ?J = ±1. The observed peaks are in the region of yellow reddish light of Sm3+. Experimental results verify that the optimum Sm3+ content in terms of intense luminescence for this series of phosphors was 2%. Beyond 2% of Sm3+ ions concentration, luminescence quenching occurs due to an enhanced probability of the energy transfer from one Sm3+ to another that matches in energy via cross-relaxation and dipole-dipole interactions according to Dexter theory. A suitable energy transfer model between two adjacent Sm3+ ions in the ZnB2O4 phosphors was accomplished by the electric dipole-dipole interaction. The critical transfer distance (Rc) for non-radiative energy transfer was found to be 21.52 Å at 2 mol % Sm3+ doped ZnB2O4. Additionally, thermoluminescence (TL) glow curves of undoped and Sm activated ZnB2O4 under beta irradiation of 10 Gy are also discussed here. © 2018 Elsevier B.V.Firat University Scientific Research Projects Management Unit FAY-2015-4735, FDK-2017-7905This work was supported by the Commission of Scientific Research Projects of Uludag University , Project number OUAP(F)-2015/31 and the Research Fund of the Cukurova University, Turkey (Project Number: FAY-2015-4735 and FDK-2017-7905 )

Doping Sm3+ into ZnB2O4 phosphors and their structural and cathodoluminescence properties

WOS: 000429838900032In this study, ZnB2O4:xSm(3+) (0.01 H-6(7/2) located at 606 nm can occur as hypersensitive transition having the selection rule Delta J = +/- 1. The observed peaks are in the region of yellow reddish light of Sm3+. Experimental results verify that the optimum Sm3+ content in terms of intense luminescence for this series of phosphors was 2%. Beyond 2% of Sm3+ ions concentration, luminescence quenching occurs due to an enhanced probability of the energy transfer from one Sm3+ to another that matches in energy via cross-relaxation and dipole-dipole interactions according to Dexter theory. A suitable energy transfer model between two adjacent Sm3+ ions in the ZnB2O4 phosphors was accomplished by the electric dipole-dipole interaction. The critical transfer distance (R-c) for non-radiative energy transfer was found to be 21.52 angstrom at 2 mol % Sm3+ doped ZnB2O4. Additionally, thermoluminescence (TL) glow curves of undoped and Sm activated ZnB2O4 under beta irradiation of 10 Gy are also discussed here. (C) 2018 Elsevier B.V. All rights reserved.Commission of Scientific Research Projects of Uludag University [OUAP(F)-2015/31]; Cukurova University, Turkey [FAY-2015-4735, FDK-2017-7905]This work was supported by the Commission of Scientific Research Projects of Uludag University, Project number OUAP(F)-2015/31 and the Research Fund of the Cukurova University, Turkey (Project Number: FAY-2015-4735 and FDK-2017-7905)

Thermoluminescence glow curve analysis and kinetic parameters of Eu doped Li2MoO4 ceramic phosphors

LiMoO4: x Eu ceramic phosphors with x = 0.5, 1, 2, 3, 5, and 7 mol% were synthesized using a gel combustion method. X-ray diffraction (XRD) measurements confirmed a rhombohedral structure (space group R-3) of synthesized compounds. Following irradiation with 50 Gy beta dose, the sample doped with 5 mol% Eu exhibited the highest integrated thermoluminescence (TL) intensity. In order to evaluate dose-response, samples were irradiated with beta radiation for 10-1000 Gy. TL intensity with 1000 Gy dose without saturation yielded the highest integrated value. Different methods were employed to determine the number of peaks, the trap structure, and the kinetic parameters of the thermoluminescence glow curve of Eu doped Li2MoO4: the Hoogenstraaten method, the Booth-Bohun-Parfianovitch method, the initial rise method (IR), combined with the T-M-T-stop experiment, various heating rates (VHR), and glow curve fitting with two different software packages. Based on the glow curve deconvolution obtained using both software packages, the component TL glow peaks present in the complex glow curve are composed of well-isolated nine overlapping glow peaks. Two software packages have shown quite similar activation energies and frequency factors.I?zmir Bak?r?ay University Scientific Research Projects Coordination Unit [GDM.2021.003]Acknowledgement This work was supported by I?zmir Bak?r?ay University Scientific Research Projects Coordination Unit, under grant number GDM.2021.003