Browsing by Author "Arslanlar, YT"
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Item Radioluminescence Properties of Copper- and Terbium-Implanted Strontium TitanateArslanlar, YT; Kibar, R; Çetin, A; Canimoglu, AIn this study, the effects of Cu and Tb implantation on the radioluminescence (RL) properties of unimplanted and Cu- and Tb-implanted SrTiO3 (STO) crystals were investigated. The changes induced by heavy ion implants of the surface clearly modify the initial strong RL signals seen near 400750nm. During heating there are step increases in intensity at the RL spectrum near 60, 40, and 82K for unimplanted and Cu- and Tb-implanted samples, respectively.Item Thermally stimulated luminescence glow curve structure of β-irradiated CaB4O7:DyAkin, A; Ekdal, E; Arslanlar, YT; Ayvacikli, M; Karali, T; Can, NThermally stimulated luminescence glow curves of CaB4O7:Dy samples after beta-irradiation showed glow peaks at similar to 335, 530 and 675 K, with a heating rate of 2 K/s. The main peak at 530 K was analyzed using the T-max-T-stop method and was found to be composed of at least five overlapping glow peaks. A curve-fitting program was used to perform computerized glow curve deconvolution (CGCD) analysis of the complex peak of the dosimetric material of interest. The kinetic parameters, namely activation energy (E) and frequency factor (s), associated with the main glow peak of CaB4O7:Dy at 520 K were evaluated using peak shape (PS) and isothermal luminescence decay (ILD) methods. In addition, the kinetics was determined to be first order (b = 1) by applying the additive dose method. The activation energies and frequency factors obtained using PS and ILD methods are calculated to be 0.72 and 0.72 eV and 8.76 x 10(5) and 1.44 x 106/s, respectively. Copyright (C) 2014 John Wiley & Sons, Ltd.Item Luminescence behavior and Raman characterization of jade from TurkeyArslanlar, YT; Garcia-Guinea, J; Kibar, R; Çetin, A; Ayvacikli, M; Can, NResults are presented for the cathodoluminescence (CL), radioluminescence (RL) and thermoluminescence (TL) of jade from Turkey. Jade samples show broad band luminescence from green to red, which, using lifetime-resolved CL, reveals seven overlapping emissions, of which two are dominant. Green emission obtained using spatially resolved CL was associated with Mn2+ and emission bands centered near at 480 and 530 nm were attributed to P-3(0)-H-3(4) and D-1(2)-H-3(4) transitions of Pr3+, respectively. Different shifts of the peak-wavelengths for 326 and 565 nm were observed with varying jade compositions. The incorporation of the larger K ion causes non-linear variations of the cell dimensions and therefore changes in the Fe-O band distance. We suggest that stress of the jade structure can be linked to the luminescence emission at 326 nm. Raman spectra have also been recorded in order to provide an unequivocal identification of the type of jade. The mechanism for the luminescence of the jade is considered. (C) 2011 Elsevier Ltd. All rights reserved.Item Detailed luminescence (RL, PL, CL, TL) behaviors of Tb 3+and Dy 3+doped LiMgPO4 synthesized by sol-gel methodKeskin, IÇ; Türemis, M; Kati, MI; Gültekin, S; Arslanlar, YT; Çetin, A; Kibar, RItem Determination of thermoluminescence kinetic parameters of white and blue chalcedony exposed to X-ray irradiationKeskin, IÇ; Kati, MI; Türemis, M; Çetin, A; Arslanlar, YT; Kibar, RThe study reveals the thermoluminescence (TL) properties of white and blue chalcedony minerals which this mineral mined two different regions (Edirne and Eskisehir, respectively) of Turkey. With the help of various characterization techniques (such as X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR)), the gem-quality of the samples was tested. The TL glow curves of the samples irradiated with X-rays show intense main TL glow peak having the maximum temperatures at 100 degrees C and 121 degrees C with a heating rate of 2 degrees C/s, respectively. The TL kinetic parameters of the samples are reported here for the first time. Activation energy (E), frequency factor (s) and the order of kinetics (b) of these peaks have been determined in detail by using various heating rates (VHR) and peak shape (PS) methods and verified by Computerized Glow Curve Deconvolution (CGCD). The CGCD method was used to determine the number of peaks associated with the n, glow curves. The values of E calculated with these three methods are a good agreement.Item Kinetic parameters and luminescence properties of rare earth (Tb, Nd) doped and transition metal (Mn) doped/co-doped YAlO3 prepared via sol-gel methodGökce, S; Keskin, I; Kati, MI; Kibar, R; Çetin, A; Arslanlar, YTIn this work, phosphor materials with the formula YAlO3 were synthesized via sol-gel method by using the stoichiometric amounts of yttrium nitrate and aluminum nitrate as base materials. The obtained phosphors were doped/co-doped with Tb3+, Nd3+ rare earth ions and Mn2+ transition metal ion. For evaluating the influence of the dopants, the grain size and morphology of the samples by scanning electron microscopy (SEM) and the phase and crystallinity of the synthesized materials by X-ray diffraction (XRD) were investigated. Optical absorption spectra, photoluminescence (PL) and thermoluminescence (TL) were performed to determine a relationship the changing dopant on luminescence properties of YAlO3. Moreover, the kinetic parameters namely activation energy (E), order of kinetics (b) and frequency factor (s) of the synthesized pure and doped materials were calculated using Computerized Glow Curve Deconvolution (CGCD) and Peak Shape Method for a better understanding of the optical properties that change with the doping process. Strong green emission was detected in the sample doped with Mn2+ correspond to 4T1(G)-> 6A1(S) transition. As for YAlO3: Nd3+, characteristic emissions originated from 4G11/2 -> 4I9/2 (-423 nm), 4G9/2 -> 4I9/2 (-460 nm) and 4G7/2 -> 4I9/2 (-540 nm) transitions were seen. The optical band gap of undoped sample was calculated as 2.79 eV and depending on the presence of Nd3+ and Tb3+ dopant ions this value was decreased to the range 2.46-2.56 eV.Item Thermoluminescence response and kinetic parameters of Tb-doped GdCa4O(BO3)3 under beta irradiationAlajlani, Y; Bulcar, K; Oglakci, M; Kaynar, UH; Arslanlar, YT; Topaksu, M; Correcher, V; Can, NIn 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 degrees C following a 50 Gy beta dose with a heating rate of 2 degrees C/s, with the primary peak (similar to 190 degrees 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 (T-m) 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.Item Rare Earth Photoluminescence in Bismuth-Germanate CrystalsArslanlar, YT; Kotan, Z; Kibar, R; Canimoglu, A; Can, NIn the present work, the photoluminescence (PL) spectra of bismuth germanate (BGO) doped with trivalent rare earth element (REE) ions with different doping concentrations (0.03wt% Eu, 0.4wt% Tm, and 1.1wt% Nd) are reported in the temperature range from 10 to 300K using different detectors, namely, photomultiplier tube (PMT), InGaAs (IGA), and Si. The luminescence in the NIR region was also measured at room temperature. Two broad emission bands attributed to undoped BGO were found at circa 1350 and 1800nm, respectively. The broad-band emissions are replaced by narrow-band line emissions defined by the trivalent rare earth dopants. The emission spectra from rare earth ion-doped BGO extend from 500 to 2000nm. Rare earth ions act as the dominant recombination centers and define the emission spectra. This is interpreted as resulting from direct charge transfer from intrinsic defect traps to rare earth recombination centers. The temperature-dependent luminescence of BGO doped with 0.4wt% Tm is also presented.Item Structural and thermal insights into the luminescent behavior of Dy3+-Doped BaZrO3 with alkali metal codopants under UV radiationArslanlar, YT; Alajlani, Y; Coban, MB; Kaynar, UH; Aydin, H; Örücü, H; Guinea, JG; Can, NThis study investigates the structural, thermal, and photoluminescent properties of Dy3+-doped BaZrO3 (BZO) perovskites, synthesized via a co-precipitation method, incorporating alkali metal codopants (Li+, Na+, and K+). Xray diffraction (XRD) analysis confirmed the retention of the cubic perovskite phase following doping, with Rietveld refinement further revealing minor lattice distortions due to Dy3+incorporation. The Williamson-Hall (W-H) analysis revealed average crystallite sizes of 53 nm and 66 nm for undoped and 0.01 Dy3+-doped BaZrO3, respectively, with corresponding micro-strain values of 1.79 x 10-3 and 1.81 x 10-3, suggesting lattice distortions due to incorporation of Dy3+. Fourier transform infrared (FTIR) spectroscopy confirmed the cubic perovskite structure and subtle structural modifications upon doping. Notably, the absence of moisture-related peaks highlights the effectiveness of the synthesis process, including rigorous drying and calcination steps that prevented hydrous species. Photoluminescence (PL) analysis of Dy3+-doped BaZrO3 exhibited three prominent emission peaks at 452 nm, 573 nm, and 656 nm under 368 nm excitation. These peaks correspond to the characteristic intra-4f electronic transitions of Dy3+ ions, specifically, 4I13/2 to 6H15/2, 4F9/2 to 6H13/2, and 4F9/2 to 6H11/2, representing blue, yellow, and red emissions, respectively. Photoluminescence decay studies showed multi-exponential behavior, with the average lifetime decreasing from 641 mu s in undoped BZO to 492 mu s in Dy3+- doped samples attributed to enhanced non-radiative recombination pathways. Among the codopants, Li+ demonstrated the most significant improvement in luminescence intensity and thermal stability by mitigating defects and optimizing charge compensation.Item Enhancement of the luminescence intensity by co-doping Mn2+ into Er3+-doped SrAl2O4de Herval, LKS; Arslanlar, YT; Ayvacikli, M; Iikawa, F; Nobrega, JA; Pizani, PS; Gobato, YG; Can, N; Henini, M; de Godoy, MPFStructural and optical properties of erbium- and manganese-doped strontium aluminates (SrAl2O4) phosphor materials synthesized by a solid state reaction were investigated. The samples presented the fundamental optical transitions due to Er3+ and Mn2+ which are typical features of the well-diluted doping process. A significant enhancement of the Er3+ optical emission band at 1530 nm was observed when the matrix is co-doped with Mn. Photoluminescence intensity under ultraviolet excitation was three times larger as compared to samples without Mn content. A model of energy transfer mechanism from Mn2+ to Er3+ ions due to optical energy matching is proposed to explain the experimental results. This result, presented first time, can be applied as useful tool for developments in optical communications. (C) 2015 Elsevier B.V. All rights reserved.