KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Search Results

Now showing 1 - 10 of 25

Some of the metrics are blocked by your
consent settings
Development of BaO-containing radiation-shielding glass using natural dolomite as a raw-material component
(2027-01-01)
Cheewasukhanont, W.
;
Kothan, S.
;
Tungjai, M.
;
Intachai, N.
;
Ruangtaweep, Y.
This study investigates the incorporation of dolomite (CaMg(CO<inf>3</inf>)<inf>2</inf>) as a natural substitute for synthetic CaO in the fabrication of radiation shielding glass (RSG). Dolomite samples from Kanchanaburi, Thailand, were characterized using X-ray fluorescence (XRF) to determine their chemical composition, revealing CaO (76.59-79.84 wt%) and MgO (19.13-21.54 wt%) as the primary components. These dolomites were used to synthesize borosilicate-based host glasses, where density remained stable (∼2.5 g/cm3), ensuring structural integrity. Optical transmittance measurements showed an average 80% transparency in the visible range. To enhance radiation attenuation, BaO was incorporated into the glass matrix at varying concentrations (5-35 mol%). Increasing BaO content increased the density of the glass samples, which contributed to improved radiation attenuation performance. The radiation-shielding properties, predicted using WinXCom over a wide photon energy range and experimentally evaluated at 0.662 MeV, improved with increasing BaO content. The HVL, Pb-equivalent thickness, and EABF results further supported the enhanced attenuation performance of the developed glasses, indicating that higher BaO content reduced the contribution of scattered photons to absorbed energy buildup in the intermediate-energy region. In addition, preliminary glass-forming tests of the B4 composition demonstrated the feasibility of preparing a larger glass sheet under similar melting and annealing conditions, although further optimization is still required. These findings suggest that natural dolomite can serve as a useful raw-material component for developing BaO-containing radiation-shielding glass with balanced optical transparency, density, and attenuation performance.
Some of the metrics are blocked by your
consent settings
Radioluminescence properties of silicate-phosphate glass system based on “Huta Ginjang” quartz sand co-doped with Gd3+/Tb3+ ions for scintillation applications
(2026-11-01)
Rajagukguk, J.
;
Hutahaean, Juniar
;
Situmorang, Howard
;
Sarumaha, C. S.
;
Simanullang, E.
A series of mixed silicate-phosphate glasses co-doped with Gd3+/Tb3+ ions at varying Tb concentrations were successfully synthesized using the melt-quenching technique. Their physical, optical and luminescence properties were analyzed, with an emphasis on the role of Tb3+ concentration. The photoluminescence (PL) spectra exhibit characteristic emission bands corresponding to Gd3+ and Tb3+ ions. A gradual decrease in the Gd3+ emission intensity at 311 nm is observed, accompanied by the suppression of Tb3+ emissions originating from the 5D<inf>3</inf> level. In contrast, a significant enhancement of the green emission associated with the Tb3+5D<inf>4</inf> → 7F<inf>j</inf> transitions is clearly evident. Under X-ray excitation, the radioluminescence (RL) spectra of the glasses displayed multiple sharp emission peaks corresponding to Tb3+ transitions, in contrast to the broad 478 nm emission band of the BGO crystal. Integral RL intensity ratios were demonstrated; all glasses exhibit significant radioluminescence intensity under X-Ray excitation compared to BGO, with QSPCaBaGd<inf>5</inf>Tb<inf>2.0</inf> showing the highest performance reaches up to 52.09% in the 350-800 nm range. These results, together with X-ray imaging capability, demonstrate that the developed glasses are promising candidates for cost-effective scintillation applications.
Some of the metrics are blocked by your
consent settings
Enhanced luminescence and scintillation performance of Ce-doped silico- and germanophosphate glasses for ultra-high resolution synchrotron X-ray imaging applications
(2026-06-15)
Sarumaha, C. S.
;
Kaewnuam, E.
;
Kantuptim, P.
;
Nishikawa, A.
;
Kato, T.
Ce-doped phosphate, silicophosphate and germanophosphate glasses with the composition 25Li<inf>2</inf>O+ 10ZnO+ 5Gd<inf>2</inf>O<inf>3</inf>+xR+ (59.5-x)P<inf>2</inf>O<inf>5</inf>+ 0.5CeF<inf>3</inf> (x = 0, 10 mol%; R = SiO<inf>2</inf> and GeO<inf>2</inf>) were prepared by the conventional melt quenching. This study highlights the novel role of network modification (SiO<inf>2</inf> and GeO<inf>2</inf> substitution) in enhancing the scintillation and imaging performance of Ce3 + -activated phosphate-based glasses; this topic remains inadequately researched. Structural analyses (FTIR, Raman) demonstrated that network modifications influence density and optical properties, with germanophosphate showing the highest density (3.07 g/cm3) and high transparency of around 80%. Notably, silicophosphate glass exhibits ∼12 times higher photoluminescence intensity than phosphate glass, with an experimental quantum yield of 24.8%. Under X-ray excitation, strong emission bands were observed from Gd3+ (310 nm) and Ce3+ (∼337 nm). The integrated ratio of radioluminescence (RL) emission was calculated and followed the order silicophosphate > phosphate > germanophosphate, indicating optimal luminescence enhancement via Si incorporation. The superior scintillation response of the silicophosphate glass is further validated by pulse height measurements under 241Am α-ray excitation. Silicophosphate glass was selected for its superior scintillation response, further confirmed by 2D/3D imaging and line-pair (MTF and contrast) analyses, demonstrating its suitability for ultra-high-resolution synchrotron X-ray imaging applications.
Some of the metrics are blocked by your
consent settings
FDTD analysis of optical integration between SiGe waveguides and Ge-rich SiGe heterostructures on graded buffer for quantum-confined Stark effect optical modulators
(2026-02-01)
Khongpetch, N.
;
Limsuwan, P.
;
Tangsangiumvisai, N.
;
Chaisakul, P.
Ge-rich SiGe heterostructures with superior crystal and photonic quality have been enabled via a thick linear graded SiGe buffer platform on Si. Nevertheless, due to a very low refractive index contrast between the Ge-rich SiGe heterostructures and the graded buffer, it is challenging to have efficient optical integration with other photonic components. In this paper, a coupling scheme based on a top adiabatic coupling between Ge-rich SiGe heterostructures on graded buffer and a SiGe waveguide in SiO<inf>2</inf> cladding is proposed to address a low-loss coupling of the Ge-rich SiGe heterostructures with a high-index-contrast waveguide structure. 3D-FDTD simulations demonstrate that efficient optical coupling between the top SiGe waveguide (high-index-contrast platform) and Ge-rich SiGe heterostructures on a thick graded buffer (low-index-contrast platform) can be adiabatically achieved with practical fabrication tolerance. In addition, the proposed coupling structure can be potentially applied with Ge/SiGe MQWs, enabling SiGe waveguide integrated Ge/SiGe MQWs optical modulator with a viable integrated extinction ratio and insertion loss performance.
Some of the metrics are blocked by your
consent settings
DEVELOPMENT AND EXPERIMENTAL CHARACTERIZATION OF AN IOT-CONTROLLED RGB LED LIGHTING SYSTEM FOR HYDROPONIC APPLICATIONS
(2026-01-01)
Worsoongnern, S.
;
Yindeesuk, W.
;
Kamoldilok, S.
;
Srinuanjan, K.
;
Limsuwan, P.
This study presents the development of an Internet of Things-based RGB LED lighting system for precise, flexible light control in hydroponic plants. The system consists of 480 high-power RGB LEDs controlled by an ESP8266 microcontroller, enabling real-time adjustment of light intensity, photoperiod, and color ratios via a smartphone. Pulse-width modulation duty-cycle modulation enables the generation of white light suitable for different stages of plant growth. Experimental results show a linear correlation between illuminance and duty cycle for all color channels. Spectral analysis confirms stable emission within the photosynthetically active radiation range (400–700 nm), with the spectral composition remaining unchanged even when brightness is reduced (dimming). The system demonstrates high control accuracy and adaptability for regulating plant growth lighting, particularly for leafy vegetables such as lettuce.
Some of the metrics are blocked by your
consent settings
Enhancement of gamma and X-ray shielding behaviors in ZnO-B2O3 glasses via La2O3 addition: Experimental and theoretical investigations
(2025-12-01)
Yabsantia, S.
;
Wantana, N.
;
Chusin, T.
;
Kaewjaeng, S.
;
Ornketphon, O.
Radiation shielding materials are crucial for reducing radiation exposure. Traditional materials such as lead, and concrete pose challenges related to toxicity and lack of transparency. This study aimed to assess the effects of lanthanum oxide (La<inf>2</inf>O<inf>3</inf>) addition on physical, optical, and radiation shielding properties of ZnO–B<inf>2</inf>O<inf>3</inf> glass systems. Glass samples of (80-x)B<inf>2</inf>O<inf>3</inf>–20ZnO-xLa<inf>2</inf>O<inf>3</inf> (x = 5–20 mol%) were prepared using the melt-quenching technique and characterized for density, molar volume, refractive index, transmittance and X-ray diffraction (XRD). Gamma-ray shielding performance was evaluated using the Compton scattering method with a Cs-137 source and NaI(Tl) detector, alongside theoretical data from WinXCOM. X-ray shielding capabilities were determined through experimental transmission measurements and Monte Carlo simulations (PHITS) across effective energies ranging from 30.40 to 44.21 keV. Increasing La<inf>2</inf>O<inf>3</inf> content (5–20 mol%) resulted in higher density (2.89–3.63 g/cm3), slightly increased molar volume (29.37–33.98 cm3/mol), and higher refractive index (1.58–1.65). All La<inf>2</inf>O<inf>3</inf>-added glasses exhibited ∼75 % transmittance in the visible region. XRD analysis indicated amorphous characteristics for all samples. For gamma rays, both experimental and theoretical results agreed well, showing improved shielding with higher La<inf>2</inf>O<inf>3</inf> levels. For lowest gamma-ray energy, the 20 mol% sample had the highest mass attenuation coefficient (μ<inf>m</inf>) of 0.21 cm2/g, lowest half value layer (HVL) of 0.89 cm, and shortest mean free path (MFP) of 1.29 cm. For X-rays, PHITS simulations and experiments also aligned, with μ<inf>m</inf> up to 4.21 cm2/g (at 30.40 keV), HVL of 0.05 cm, and MFP of 0.07 cm. These findings suggest that La<inf>2</inf>O<inf>3</inf> addition enhances both gamma and X-ray shielding effectiveness. In conclusion, the study highlights the potential of La<inf>2</inf>O<inf>3</inf>-added ZnO–B<inf>2</inf>O<inf>3</inf> glass as an alternative shielding material, with future research aimed at further improving its shielding performance.
Some of the metrics are blocked by your
consent settings
Ca co-doped CsI(Tl) crystal scintillator for γ- and X-ray detecting applications
(2025-01-01)
Tariwong, Y.
;
Kim, H. J.
;
Quang, Nguyen Duy
;
Khan, Arshad
;
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.
Some of the metrics are blocked by your
consent settings
A novel material for radiation detection application of zinc bismuth lithium borotellurite glass doped with Dy2O3
(2024-12-01)
Sommat, V.
;
Ornketphon, O.
;
Kaewjaeng, S.
;
Kothan, S.
;
Limsuwan, P.
Radiation detection glass with the following chemical composition B<inf>2</inf>O<inf>3</inf>–TeO<inf>2</inf>–Li<inf>2</inf>O<inf>3</inf>–Bi<inf>2</inf>O<inf>3</inf>–ZnO doped with Dy<inf>2</inf>O<inf>3</inf> where x = 0.00, 0.10, 0.50, 1.00, 1.50 and 2.00 mol%, was developed for the characterization of physical properties such as density, molar volume (V<inf>m</inf>), and refractive index, optical absorption, luminescence, CIE's diagram, and radiation detection properties. The density and refractive index of glass samples increase with the increase of Dy<inf>2</inf>O<inf>3</inf> composition. The optical property of glass shows eight strongest peaks from 6H<inf>15/2</inf> centering at 263 nm (4I<inf>13/2</inf> + 4F<inf>7/2</inf>), 298 nm (4G<inf>11/2</inf>), 357 nm (4I<inf>15/2</inf>), 803 nm (6F<inf>5/2</inf>), 897 nm (6F<inf>7/2</inf>), 1090 nm (6H<inf>7/2</inf> + 6F<inf>9/2</inf>), 1272 nm (6F<inf>11/2</inf> + 6H<inf>9/2</inf>) and 1671 nm (6H<inf>11/2</inf>), respectively. The emission peaks are r (4F<inf>9/2</inf>), 481 nm (6H<inf>15/2</inf>), 575 nm (6H<inf>13/2</inf>), 664 nm (6H<inf>11/2</inf>), and 751 nm (6H<inf>9/2</inf>) under excited at 453 nm (4F<inf>9/2</inf>), respectively. The excitation peaks under emission at 575 nm from 6H<inf>15/2</inf> centering at 350 nm (6P<inf>7/2</inf>), 365 nm (4P<inf>3/2</inf>), 388 nm (4K<inf>17/2</inf>), 425 nm (4G<inf>11/2</inf>), 453 nm (4I<inf>15/2</inf>), and 471 nm (4F<inf>9/2</inf>) respectively. The study of luminescence characteristics, which includes emission, excitation, and CIE diagrams, reveals white emission bands that coincide with the CIE diagram. Furthermore, measuring the parameters of the thermoluminescence dosimeter (TLD) recorded with a heating rate of 5 °C/s in the temperature up to a maximum of 400 °C yields good results in low dose radiation detection. Based on all the results, it was determined that this glass can be a candidate for radiation detection materials in the future.
Some of the metrics are blocked by your
consent settings
Fabrication luminescence and radiation shielding properties of Gd2O3–La2O3–ZnO–B2O3–Sm2O3 glasses
(2023-01-01)
Kaewjaeng, S.
;
Kothan, S.
;
Wantana, N.
;
Kim, H. J.
;
Rajaramakrishna, R.
The purpose of developing high transparency radiation shielding materials and luminescence materials with stoichiometric ratio of xGd<inf>2</inf>O<inf>3</inf>:10La<inf>2</inf>O<inf>3</inf>:10ZnO:(79-x) B<inf>2</inf>O<inf>3</inf>: 1Sm<inf>2</inf>O<inf>3</inf> where x = 0, 5, 10, 15, and 20 mol% using melt quenching technique. The physio-optical properties such as molar volume, density, concentration of rare-earth ions, polaron radius, inter-ionic radius, optical basicity, average distance between rare-earth ions, and optical packing density of the present glasses has been evaluated. The glass samples obtained show high density which is vital factor for radiation shielding. The absorption spectra show significant of bands Sm3+ ions. The FTIR results of Gd-La-Zn-B-Sm (Gd-1Sm) glass samples show signature borate BO<inf>3</inf> and BO<inf>4</inf> vibrational units in Gd-1Sm glass samples. The μ, μ<inf>m</inf>, HVL, TVL, and MFP were evaluated and showed that the values decrease with increasing X-ray energy whereas increase with an increase in Gd<inf>2</inf>O<inf>3</inf> content suggesting their potential use in X-ray diagnosis regions. The HVL value was compared with commercial windows, concrete, Serpentine and X-ray windows and found that the glasses doped with 10 mol%, 15mol%, and 20 mol% Gd<inf>2</inf>O<inf>3</inf> content showed better results than X-Ray windows at 10 kVp. The emission and excitation spectra of glass samples were studied and emission spectra show orange emission bands. The experimental lifetime analysis shows that the glass samples show decreasing trend from 1.161 to 1.128 ms with an increase in Gd3+ ions exhibiting single exponential nature.
Some of the metrics are blocked by your
consent settings
Radio and photo luminescence properties of Dy3+ ion doped bismuth barium gadolinium borate glass
(2023-01-01)
Ruamnikhom, R.
;
Yasaka, P.
;
Boonin, K.
;
Limsuwan, P.
;
Kaewkhao, J.
Investigations on physical, optical and photo – radio luminescence properties of dysprosium doped bismuth barium gadolinium borate glass (BiBaGdBDy) have been prepared for the melt at 1200 °C and rapidly cooling in the casting process. The glasses were doped by Dy<inf>2</inf>O<inf>3</inf> with six concentrations which varied from 0.00 to 1.50 mol%. The cut and polished glass samples were measured density and refractive index at room temperature. The absorption spectra show at the wavelength 802, 891, 1083, 1265 and 1679 nm that that are matched with the transition of Dy3+ from 6H<inf>15/2</inf> (ground state) to various excited state 6F<inf>5/2</inf>, 6F<inf>7/2</inf>, 6F<inf>9/2</inf>, 6F<inf>11/2</inf> and 6H<inf>11/2</inf> respectively. The 387 nm flash lamp was used to excite the sample lead to display the five emission bands at 481, 576, 661 and 753 nm which matched with the emission transitions 4F<inf>9/2</inf>→6H<inf>J</inf> (J = 15/2, 13/2, 11/2 and 9/2) respectively. The prominent blue light from 4F<inf>9/2</inf>→6H<inf>15/2</inf> and yellow light from 4F<inf>9/2</inf>→6H<inf>13/2</inf> emissions was combined and produces white light emission, which is confirmed by the CIE chromaticity diagram. The certain Lifetime of important laser-level is 4F<inf>3/2</inf>, which shows a decreasing trend with the increase of Dy<inf>2</inf>O<inf>3</inf> concentration. The Judd-Ofelt (J-O) intensity parameters found the trend Ω<inf>2</inf> > Ω<inf>4</inf> > Ω<inf>6</inf>. The branching ratios (β<inf>R</inf>) transition probabilities (A<inf>R</inf>) and stimulated emission cross-sections (σ<inf>e</inf>) were estimated for 4F<inf>9/2</inf>→6H<inf>13/2</inf> transition they are the radiative properties that were used to figure out the potential benefit of these glasses for laser action in the visible region along these lines suggests that the present Dy3+ doped bismuth barium gadolinium borate glasses are suitable for white light applications and scintillator material.

KMITL

Browse

Filters

Settings

Sort By

Results per page

Search Results