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Ca co-doped CsI(Tl) crystal scintillator for γ- and X-ray detecting applications
(2025-01-01)
Tariwong, Y.
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Kim, H. J.
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Quang, Nguyen Duy
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Khan, Arshad
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Daniel, D. Joseph
The vertical Bridgman method is used for the growth of single-doped CsI(Tl) and CsI(Tl:Ca) crystals, which has been evaluated for feasible applications in X-ray imaging and radiation detection. The powder XRD technique study reveals a single-crystalline phase of the grown crystal. The emission spectra show a broad emission band with a maximum of 540 nm under X-ray excitation, along with the characteristic emissions that arose from the Tl+ intra-center transition. The scintillation qualities of the grown crystal were studied via the pulse height spectra, scintillation light yield, energy resolution, and scintillation decay time. Pulse shape discrimination (PSD) was investigated under γ-rays and α-particles excitation sources. Moreover, the X-ray imaging application was investigated by an X-ray synchrotron at the Synchrotron Light Research Institute to study the performance of the grown crystal. These preliminary investigations suggest that the grown CsI(Tl:Ca) crystal can be one of the promising crystals for γ- and X-ray detecting applications.
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Enhanced electrical and energy storage performances of Fe, Sb co-doped BNBCTS ceramics synthesized via the solid-state combustion technique
(2024-12-01)
Kornphom, C.
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Saenkam, K.
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Yotthuan, S.
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Vittayakorn, N.
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Bongkarn, T.
In this study BNBCTS ceramics were co-doped with Fe and Sb to form (Bi<inf>0.5</inf>Na<inf>0.5</inf>)<inf>0.93</inf>(Ba<inf>0.945</inf>Ca<inf>0.055</inf>)<inf>0.07</inf>(Ti<inf>(0.9946-x)</inf>Sn<inf>0.0054</inf>)(Fe<inf>0.5</inf>Sb<inf>0.5</inf>)<inf>x</inf>O<inf>3</inf> ceramics (denoted as BNBCTS-xFS) with various x content and were prepared via the solid-state combustion technique to enhance the electrical and energy storage performance. The effect of co-doping Fe and Sb on the phase formation, defect dipole, microstructure, electrical and energy storage properties of BNBCTS-xFS ceramics was studied. When x content increased from 0.0 to 0.030, the amount of the rhombohedral (R) phase decreased from 51 to 24 % while the tetragonal (T) phase increased from 49 to 76 %. The increased Fe and Sb content increased the defect dipole of singly/doubly charged oxygen-vacancies (V<inf>O</inf>∙/ V<inf>O</inf>∙∙) and caused more Ti4+ to transition to Ti3+, which caused the transition temperature of the ferroelectric phase to relaxor state (T<inf>F-R</inf>) in the ceramics to drop to below room temperature and it exhibited relaxor characteristics at room temperature. The ceramic with an x content of 0.010 had the largest grain size (3.06 μm), excellence ferroelectric properties (P<inf>r</inf> ∼31.04 μC/cm2, P<inf>m</inf> ∼38.98 μC/cm2 and E<inf>c</inf> ∼18.28 kV/cm), the largest electro strain (∼0.175 %) and a large d<inf>33</inf>* of 350 pm/V. Moreover, when x = 0.020, the ergodic relaxor ceramic showed the smallest grain size (1.03 μm), the lowest remanant polarization (P<inf>r</inf>) of 4.52 μC/cm2 and the lowest coercive field (E<inf>c</inf>) of 8.37 kV/cm, at an electric field of 60 kV/cm. More importantly, energy storage properties at the electric breakdown strength (E<inf>b</inf> = 120 kV/cm) of the ceramics with an x content of 0.020 exhibited a recoverable energy storage density (W<inf>rec</inf>) of 1.81 J/cm3, a total energy storage density (W<inf>total</inf>) of 2.95 J/cm3 and an efficiency (η) of 61.30%, with excellent thermal (∼25–150 °C) and frequency stability (∼1–100 Hz). This study provides new insights into the modulation of BNBCTS ceramics with Fe and Sb co-doping, which could effectively improve the electrical properties and energy storage properties of BNBCTS-xFS ceramics.
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Novel Tb3+ doped borophosphate glass scintillator for X-ray imaging
(2024-10-01)
Khrongchaiyaphum, F.
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Wantana, N.
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Kaewnuam, E.
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Pakawanit, P.
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Phoovasawat, C.
In this study, we introduce an efficient green-emitting material made from Tb3+ doped borophosphate scintillating glass for X-ray imaging. An influence of Tb<inf>2</inf>O<inf>3</inf> concentration on the physical, optical, luminescent, and scintillation properties of glasses were investigated. The glass density and refractive index increase, while the molar volume and Tb3+ inter-ionic distance decreases with Tb<inf>2</inf>O<inf>3</inf> addition. These glasses absorb the photons in range of UV, Vis, and NIR. The excitations by UV and X-ray on glasses causes the strong green emission centered around 545 nm by the 5D<inf>4</inf> → 7F<inf>5</inf> transition of Tb3+. The energy transfer from Gd3+ to Tb3+ was occurred in this emission. The glass doped with 4 mol% of Tb<inf>2</inf>O<inf>3</inf> demonstrates the highest emission intensity at 545 nm due to the concentration quenching. The decay time of glasses are in few milliseconds. The integral X-ray scintillation efficiency of 4 mol% doped glass is 52% compared to that of BGO crystal. Additionally, this glass was proceeded in the X-ray imaging and yielded the image with satisfied resolution, characteristics and MTF values, compared to that obtained from YAG:Ce crystal. The developed glass has a potential for X-ray imaging applications, especially in the medical imaging, flaw detection, and security inspection.
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Eu2O3 doped silicoborate glasses for scintillation material application: Luminescence ability and X-ray imaging
(2023-12-01)
Intachai, N.
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Kothan, S.
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Wantana, N.
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Kaewjaeng, S.
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Pakawanit, P.
The glass samples were prepared by melt quenching method and changing Eu<inf>2</inf>O<inf>3</inf> concentrations following component of xEu<inf>2</inf>O<inf>3</inf> - 40Na<inf>2</inf>O - 7.5Gd<inf>2</inf>O<inf>3</inf> - 5SiO<inf>2</inf> - (47.5-x)B<inf>2</inf>O<inf>3</inf> (x = 0, 1, 2, 3 mol %). Density and molar volume tend to increase with increasing Eu<inf>2</inf>O<inf>3</inf> concentrations, corresponding to the larger non-bridging oxygen. Fourier transform infrared spectra (FTIR) results point out that the majority BO<inf>3</inf> borate group. The absorption spectra were represented in the length of UV-Vis and NIR region. The phonon energy of 3Eu:7.5Gd was 1280.54 cm−1, related to the borate glass host. The photoluminescence and X-ray-induced luminescence spectra of 3Eu:7.5Gd glass showed similar highest intensity at 613 nm (5D<inf>0</inf>→7F<inf>2</inf>). The photoluminescence quantum yield (PLQY) of 3Eu:7.5Gd glass shows the highest value at 85.70 %. The scintillation efficiency of 3Eu:7.5Gd glass was 17.51 % of bismuth germanate (BGO) crystal. The decay time owing to Eu3+ emission is 2.054 ms for 2Eu:7.5Gd glass. The highest energy transfer efficiency was 2 mol % of Eu<inf>2</inf>O<inf>3</inf> concentrations (η<inf>ET</inf> = 70 %). The CIE chromaticity coordinates of the glasses are placed in the reddish-orange area (0.65, 0.35). The spatial resolution of X-ray imaging study was 10 lp/mm. These results suggest that 3 mol % of Eu<inf>2</inf>O<inf>3</inf> doped silicoborate glass is capable of being a scintillator applied in the X-ray imaging system.
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Eu3+ Doped Na2O-Gd2O3-BaO-B2O3-P2O5 glasses for x-ray scintillator application
(2023-11-01)
Khrongchaiyaphum, F.
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Wantana, N.
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Kansirin, S.
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Pakawanit, P.
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Vittayakorn, N.
The Na<inf>2</inf>O-BaO-B<inf>2</inf>O<inf>3</inf>-P<inf>2</inf>O<inf>5</inf> doped with varying concentrations of Gd<inf>2</inf>O<inf>3</inf> and Na<inf>2</inf>O-Gd<inf>2</inf>O<inf>3</inf>-BaO-B<inf>2</inf>O<inf>3</inf>-P<inf>2</inf>O<inf>5</inf> glasses were doped with varying concentrations of Eu<inf>2</inf>O<inf>3</inf> (referred to as Eu:NGBaPB) and prepared using the melt-quenching technique. These glasses were analyzed comprehensively in the physical, optical, chemical groups and photo-/radio- luminescence properties. Furthermore, the X-ray imaging was operated to indicate the practical radiation detection of glass. The addition of Eu<inf>2</inf>O<inf>3</inf>, the density and refractive index of Eu:NGBaPB glasses increased, while the molar volume decreased. The glass exhibited photon absorption in the UV-NIR regions. Excitation from various sources such as X-ray, ultraviolet, and visible light resulted in a reddish-orange emission at approximately 613 nm, originating from the 5D<inf>0</inf>→7F<inf>2</inf> radiation state of Eu3+. Energy transfer occurred from Gd3+ to Eu3+ within the glass. These findings highlight the intriguing potential of the glass for applications as an X-ray scintillator.
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Tribovoltaic effect: Fundamental working mechanism and emerging applications
(2023-06-01)
Sriphan, S.
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Vittayakorn, N.
The triboelectric nanogenerator (TENG) is currently a promising technology operated by coupling mechanisms between contact electrification and electrostatic induction for efficiently converting mechanical energy into electricity. Broad applications have been demonstrated practically. However, the electrical signal produced from the TENG has a pulsed alternating current output, which needs to be rectified by the circuit from alternating current to direct current (DC) appropriately for powering/storing small electronic systems. This limits utilization by the drawbacks of conversion efficiency, size, and portability. The development of a DC TENG is thus essential. This novel physical phenomenon (DC TENG) emerged just recently, mainly based on Schottky, p-n and liquid-semiconductor junctions, and a multilayered structure junction (i.e. metal/semiconductor-insulator-semiconductor), called the tribovoltaic nanogenerator (TVNG). Pair sliding from two triboelectric materials with different electronic band energies serves as continuous DC with a unique mechanism. The excited carriers (corresponding with the generated outputs) can be enhanced from the tribovoltaic effect through theoretical design, and the concept can be hybridized with other technologies. This provides the potential of in-depth study and practical demonstrations for advanced harvesting and sensing. This review comprehensively presents the origins of triboelectric and tribovoltaic effects, related to fundamental and dynamic TVNG mechanisms in various material systems, and recent progress of the TVNG in designs and applications. Moreover, the challenge and outlook are discussed lastly for the future direction of TVNG development.
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Na2O-Gd2O3-Al2O3-P2O5 glass scintillator doped with Dy3+: X-rays and proton responses
(2023-01-01)
Wantana, N.
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Kaewnuam, E.
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Tariwong, Y.
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Quang, Nguyen Duy
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Pakawanit, P.
Dy3+:Na<inf>2</inf>O-Al<inf>2</inf>O<inf>3</inf>-Gd<inf>2</inf>O<inf>3</inf>-P<inf>2</inf>O<inf>5</inf> (Dy:NAGP) glasses were fabricated to investigate the capability for radiation responses. The influence of Dy<inf>2</inf>O<inf>3</inf> concentration on glass properties was studied. The density and effective atomic number of glass increased with the addition of Dy<inf>2</inf>O<inf>3</inf> content. The glasses absorbed the photons in the ultraviolet, visible light, and near-infrared region. In photoluminescence (PL) spectra, the obvious yellow emission at 574 nm and blue emission at 482 nm of Dy3+ were both generated by the direct excitation and the Gd-Dy energy transfer. The PL decay time of glasses was in the millisecond order. There was thermal quenching observed in temperature-dependent luminescence (TDL). The radioluminescence (RL) and protonluminescence (PrL) represented the emission pattern of Dy3+ similarly to PL spectra. The concentration quenching caused 0.50Dy:NAGP glass with the highest PL and RL emission intensity. The X-ray imaging of developed glass using a synchrotron light source was successfully imaged for the first time.
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Recycling of Broken Waste Glass as Polyethylene Nanofiller for Electrical Insulating System
(2022-01-01)
Vittayakorn, W.
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Khunna, D.
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Buaphuen, P.
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Vittayakorn, N.
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Makcharoen, W.
This work focuses on the preparation of a high-quality glass powder from the broken windowpane. The expected glass powder must show a high amount of silicon dioxide with fine particle size. The processing technique used in this work is coarse grinding and high-speed vibratory milling under a variety of conditions to get the best quality of glass powder. The particle size and particle size distribution were examined by using DLS technique. The chemical composition was examined by EDX together with FT-IR and XRF spectroscopies. The results showed that the wide range of particle size distribution occurred in all milling conditions, which approximately ranged from 0.3 to 7 µm, and the 270 min-milling time showed the smallest particle size of glass powder. The chemical analysis showed that the glass powder is rich in silica which contained about 70.47% of SiO<inf>2</inf>. After that, the various ratios of the glass powder/HDPE composites were formed by using the traditional casting method. The physical and electrical properties were investigated for all composites. The results showed that after adding glass powder into the HDPE matrix, the ε<inf>r</inf> value significantly drops due to the inorganic filler suppressed polarization within the systems. For the resistivity, the ρ value significantly increases after adding glass powder to the HDPE matrix for all compositions because this filler promotes the hinder of electric current flow. Finally, it can conclude that the waste glass powder can use as a filler in the HDPE-based composite as better as the commercial SiO<inf>2</inf> powder for the electrical insulting application.
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Influence of various nanofillers on mechanical and electrical properties of epoxy resin composites
(2022-01-01)
Kitichatpayak, D.
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Makcharoen, W.
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Vittayakorn, N.
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Vittayakorn, Wanwilai
Epoxy-based composites are widely used in the aircraft, automobile, and microelectronic industries. The incorporation of various nanofillers into epoxy resins can yield high-performance composites having high strength, lightweight, and multifunctional properties. So, this work focuses on the preparation of various inorganic nanoparticles including the waste glass powder received from the broken windowpane filled in an epoxy resin matrix to create high-performance composites. The physical, chemical, mechanical, and electrical properties were investigated for all samples. The results show that the neat epoxy resin shows the lowest HV value and loses the most weight in the abrasion test. Whereas ZnO/epoxy resin composite shows the highest H<inf>V</inf>, the Al<inf>2</inf>O<inf>3</inf>/epoxy resin composite loses less weight in the abrasion test. For electrical results, the resistivity of epoxy resin composites filled with 2 wt% of Al<inf>2</inf>O<inf>3</inf> shows the highest value which is about 45% increase from the pure epoxy resin. Finally, it can be concluded that all inorganic fillers which are SiO<inf>2</inf>, Al<inf>2</inf>O<inf>3</inf>, TiO<inf>2</inf>, and ZnO including waste glass powder can really improve the hardness, abrasion resistance, and electrical resistivity of the epoxy resin.
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Coexistence of local structural heterogeneities and long-range ferroelectricity in Pb-free (1-x)Ba(Zr0.2Ti0.8) O3-x(Ba0.7Ca0.3)TiO3 ceramics
(2021-03-29)
Dey, K.
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Ahad, A.
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Gautam, K.
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Tripathy, A.
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Majid, S. S.
Environmentally benign (1-x)Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3 (BZT-BCT) ceramics are promising materials due to their remarkable high piezoresponse [Liu and Ren, Phys. Rev. Lett. 103, 257602 (2009)PRLTAO0031-900710.1103/PhysRevLett.103.257602]. In this Letter, by focusing on local and average structure in combination with macroscopic electromechanical and dielectric measurements we demonstrate the structure property relationship in the tetragonal BZT-BCT ceramic. During high-temperature cubic to tetragonal phase transformation, polar nanoregions are manifested through the spontaneous volume ferroelectrostriction at temperatures below ∼477 K. Temperature-dependent local structural investigations across the Zr K edge extended x-ray absorption fine-structure spectroscopy reveal an anomalous collaboration between the ZrO6 and TiO6 octahedra. These octahedra compromise their individuality during polarization development. The presence of domains of submicron size embedded inside the macroscopic ferroelectric regions below Tm, as well as their hierarchical arrangement, is observed by piezoresponse force microscopy. Effects of the existence of the structural/polar heterogeneities below Tm are observed also when polarizabilities of the poled and unpoled samples are compared; the poled sample is found to be more susceptible to the electric field. In addition, by using electric field dependent x-ray diffraction studies we also show that this ceramic under field exhibits a reduction of tetragonal distortion, which is consistent with earlier reports.

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