Browsing by Subject "Wet-chemical method"

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    Study of luminescence of Mn-doped CaB4O7 prepared by wet chemical method
    (Elsevier Ltd, 2016) Oguz K.F.; Ekdal E.; Aslani M.A.A.; Canimoglu A.; Garcia Guinea J.; Can N.; Karali T.
    In this study, manganese (Mn) doped Calcium Tetraborate (CaB4O7) samples were prepared by the wet chemical method. Under beta irradiated, CaB4O7:Mn showed thermally stimulated luminescence (TSL) glow peaks at approximately 85 °C and 220 °C with a heating rate of 5 °C/s. Peak shape (PS) and various heating rates (VHR) methods were applied for determining the trap parameters such as order of kinetic (b), activation energy (E) and frequency factor (s). The results indicate that the main dosimetric peak of CaB4O7:Mn follows the second-order kinetic model. The thermal fading ratio of the material is around 15% at the end of one month period of storage. The results of the TL studies carried out on the CaB4O7:Mn dosimeter revealed that it has high sensitivity, which makes it very valuable in various dosimetric applications like space, medical, personal dosimetry and dating. Radioluminescence (RL) of CaB4O7:Mn was also studied. It is shown that the RL spectrum contains a wide band centered at 530 nm assigned to Mn2+ ion emission. A broad band emission feature peaked at 350 nm assigned to the non-bridging oxygen hole center (NBOHC) is also discussed and a model is proposed to explain this broad band feature. © 2016 Elsevier B.V. All rights reserved.
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    Thermoluminescence spectra of Tm doped ZnB 2 O 4 phosphor prepared via a wet-chemical synthesis
    (Elsevier Ltd, 2019) Bulcar K.; Kucuk N.; Topaksu M.; Can N.
    In 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 Ltd
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    Thermoluminescence analysis of beta irradiated ZnB 2 O 4 : Pr 3+ phosphors synthesized by a wet-chemical method
    (Elsevier Ltd, 2019) Akca S.; Oglakci M.; Portakal Z.G.; Kucuk N.; Bakr M.; Topaksu M.; Can N.
    In this paper we describe the thermoluminescence (TL) characteristics of ZnB 2 O 4 :Pr 3+ phosphors with Pr concentrations varying between 0.2 and 1 mol% prepared by a wet-chemical method. The TL glow curves of the phosphor sample consisted of three peaks located at 71 °C (P1), 124 °C (P2) and 233 °C (P3). The TL intensity increased with the beta dose ranging from ∼0.1 to ∼20 Gy. Dose response, reproducibility and trapping parameters of TL glow curves were evaluated to clearly reveal thermoluminescence features. We observed that TL intensity of P2 and P3 peaks decreases as the heating rate increases. Trap parameters were estimated via the Hoogenstraaten, Booth-Bohun-Parfianovitch, the initial rise methods combined with T m −T stop experiment and TLanal CGCD program. Heating rates were varied to use in the Hoogenstraaten analyses. The T m −T stop investigations on regenerated TL signals for P1 and P2 peaks indicated that ZnB 2 O 4 :Pr 3+ phosphor has four electron trap levels with energy values in the range of 0.5–1.5 eV These four traps have first order kinetic and are formed at high temperature region. Resulting values are utilized as a reference for the CGCD procedure and the trapping parameters from the TL glow curves are calculated. The figure of merit (FOM) of the TL glow curve during curve fitting procedures is found to be 2.019%. The intensities of the main dosimetric peaks appeared at 124 °C and 233 °C exhibits good linear dose response up to 20 Gy. These results provide valuable knowledge for use of the characteristics of Pr doped ZnB 2 O 4 in dosimetry research, just need to eliminate low temperature TL peak. © 2019 Elsevier Ltd
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    Comparative studies on thermoluminescence characteristics of non-doped Mg2SiO4 prepared via a solid-state reaction technique and wet-chemical method: An unusual heating rate dependence
    (Elsevier Ltd, 2019) Dogan T.; Akça S.; Yüksel M.; Kucuk N.; Ayvacikli M.; Karabulut Y.; Canimoglu A.; Topaksu M.; Can N.
    Magnesium orthosilicate (Mg2SiO4)was synthesized via a traditional solid-state reaction and a wet chemical route. This study primarily reported the thermoluminescence (TL)behavior of Mg2SiO4 host. X-ray diffraction pattern revealed that Mg2SiO4 exhibits orthorhombic structure matched with JCPDS card 900-6398. Dose response, reproducibility and trap parameters of TL glow curves were evaluated to clearly reveal TL features. Two TL glow peaks situated at 81 °C and 192 °C were monitored at a heating rate of 2 °Cs−1. We observed anomalous heating rate effect for the peak centered at 192 °C whilst TL intensity of the peak at 81 °C decreases with elevating heating rate. Trap depths of the electrons within the trap centers were found to be 1.04 ± 0.01eV and 1.37 ± 0.01eV for both methods using peak shape (PS)method. Distribution of trap centers was examined using the Tmax−Tstop method and this case indicated that the glow curves consist of single TL peaks. The intensity of TL glow curves exhibited a good linear dose response under total area up to 20 Gy. A comparison of the two preparation techniques revealed that TL characteristics of this phosphor are partly dependent and Mg2SiO4 could be a promising material for dosimetric application. © 2019 Elsevier B.V.