Papers by Author: Jakrapong Kaewkhao

Abstract: The work emphasizes on energy saving in multi-layered glasses. Appropriate multi-layer designing was envisaged with various possibility and measured the transmittance of light in UV-Vis-NIR range. Various glasses were selected to study their transmittance for their specific advantages among each other for designing the multi-layer.Visible region showing higher transmittance revealing that these glasses allows more light in this range. While in the IR region these glasses show less transmittance revealing that these glasses doesn’t transmit much heat, this being the interest of study to stack the glasses for multi-layered glass with smart film then subjected to study their optical behavior and understood their energy saving phenomenon from window 6 program to obtain Solar Heat Gain Coefficient (SHGC) and Light to Solar Gain (LSG) data. Such multi-layered glasses can be used as a database in industrial plants.

Abstract: The Dy³⁺-doped glasses of the M₂O₃:CaO:SiO₂:B₂O₃ (M₂O₃ = Y₂O₃ and La₂O₃) materials have been successfully fabricated with the 0.5 % mol of the Dy₂O₃ concentration, and thoroughly investigated based on the physical, optical, photo- and radioluminescence properties. The developed glass materials were prepared from the compositions of 25M₂O₃:10CaO:10SiO₂:(55-x)B₂O₃:0.5Dy₂O₃ by the conventional melt-quenching technique at 1,400°C. The clear sample of the doped La₂O₃ glass demonstrated higher density and the molar volume than those of the doped Y₂O₃ glass. From the spectrophotometry, the absorption peaks of the Dy³⁺ ions were clearly observed in both glasses. The photoluminescence (PL) spectra of the developed glasses indicated two-colors with two strongest peaks at 577 nm (⁴F_9/2®⁶H_13/2) and 482 nm (⁴F_9/2®⁶H_15/2). In addition, the emission spectra from the radioluminescence (RL) were identical to those from the PL measurements. From the results of the PL and RL measurements, the Y₂O₃ glass had higher emission in the intensity than the La₂O₃ glass. The X-ray absorption near edge spectroscopy (XANES) with the synchrotron radiation was carried out in fluorescent-yield mode to determine the average oxidation number of the Dy ions dispersed in the glass matrices. The DyL₃-edge XANES spectra of both developed glasses were nearly identical with the sharp white line at 7795.5 eV and the edge energy of 7793 eV. Compared to the XANES spectrum of the pure Dy₂O₃ standard, both glasses showed the difference smaller than 0.5 eV, and therefore confirmed the oxidation number of the Dy ions of 3+.

Abstract: This work, gamma-ray shielding properties of the lutetium lithium borate glasses in the system Lu₂O₃ - Li₂O - B₂O₃ have been evaluated as a shielding material at 662 keV photon energy. While the experimental mass attenuation coefficients (μ_m) have been determined by using the narrow beam transmission method, the theoretical data were calculated using WinXCom program. The good agreements between experimental and theoretical values have been obtained. Both experimental and computational mass attenuation coefficients data were used to obtain the effective atomic number (Z_eff), and the effective electron density (N_el). Based on the obtained data, the Lu-based glasses have good shielding properties, the improved glasses could be used as gamma-rays shielding material.

Abstract: The physical, optical and luminescence properties of lithium aluminium phosphate glasses different doping europium oxide have been investigated to evaluate their properties for solid-state lighting applications. The density and molar volume measurements were carried out at room temperature. The absorption spectra were investigated in the UV-Vis-NIR region from 250 to 2500 nm. The emission spectra, excited with 394 nm excitation wavelength showed four emission transitions corresponding to ⁵D₀→⁷F₁ (591 nm), ⁵D₀→⁷F₂ (612 nm), ⁵D₀→⁷F₃ (648 nm) and ⁵D₀→⁷F₄ (698 nm). The optimal concentration of Eu₂O₃ in lithium aluminium phosphate glasses was 1.00 mol%.

Abstract: The work is focused to study the non-proportionality and scintillation properties of YAG:Ce scintillator by the Compton coincidence technique (CCT). The ¹³⁷Cs was used as a radioactive source with an energy 662 keV and were recorded at seven scattering angles ranging 30°-120°. The electron energy resolution, the light yield and non-proportionality were measured. It was found that, the linear relations were observed for YAG:Ce scintillator indicated that the energy resolutions are inverse proportional to the square root of energy. The results show that the light yield increases with increase in electron energy. The non-proportionality of YAG:Ce scintillator, it can be observed the crystal demonstrated good proportional property in the electron energy range. For the electron energy range below 350 keV, the electron response decreased at approximately 3.5 % over the measured energy range.

Abstract: This study is to find a parameters that necessary for fabricating a radiation shielding glass in x-ray room. In this study, we performed a comparison of commercial lead glass product commercial window, and developed lead-free glass in the composition of xBaO:20ZnO:(80-x)B₂O₃ which are applied used for lead glass replacement. The result found that, the linear attenuation coefficients (m) were increased with the increase of BaO concentrations and the decrease of an x-ray tube voltage. The developed glass samples were investigated in terms of half value layer (HVL) and mean free path (MFP) that found to be decreased with the increase of BaO concentrations which the good characteristics for application in a x-ray shielding glass manufacturing.

Abstract: Bismuth borophosphate glasses containing different doping cerium oxide have been synthesized at 1200 °C by melt-quenching technique. The doping concentration of the Ce³⁺ was varied from 0.05 mol% to 2.0 mol%. The glass samples were characterized through optical absorption and luminescence spectral measurements. UV-visible and near infrared absorption spectra of glass samples were not observed nevertheless the absorption edge was shift to the longer wavelength. The photoluminescence and radioluminescence spectra show emission bands around 367 nm under 317 nm excitation wavelength. Also, the highest emission intensity was found at 0.5 mol% CeF₃ dopant for both of photoluminescence and radioluminescence.

Abstract: In this work, the optical and luminescence properties of Dy₂O₃ doped barium phosphate glass with different alkaline earth oxides (MgO, CaO and SrO) have been investigated. The glass samples were prepared by the melt-quenching technique at the melting temperature of 1200 °C. The absorption spectra of glasses were recorded in the ultraviolet, visible and near infrared (UV-Vis-NIR) region. The absorption bands centered at 385, 424, 452, 472, 754, 803, 901, 1093, 1273 and 1683 nm, respectively have been observed. The emission spectra of glass samples centered at 482, 574, 662 and 751 nm, respectively have been observed with 350 nm excitation wavelength. The result of radioluminescence spectra were slightly different with photoluminescence spectra. The coordinate of emitting color (x, y) for 350 excitation wavelength is 0.3781 and 0.4252, respectively which is located in white light region of CIE diagram.

Abstract: Er³⁺-doped ZnO – BaO – TeO₂ glasses with the formula (80-x)TeO₂–15ZnO–5BaO–xEr₂O₃ were fabricated using melt quenching technique. The 5 glass samples with different concentrations of Er₂O₃ were prepared under atmospheric pressure. The samples were investigated on their properties: density, molar volume, absorption spectra and photoluminescence. Density was increased with an increase in Er³⁺ content. The molar volume trend is in the opposite way to that of the density. The absorption bands are assigned as absorptions from the ⁴I_15/2 ground state to the ⁴F_7/2, ²H_11/2, ⁴S_3/2, ⁴F_9/2, ⁴I_9/2, ⁴I_11/2 and ⁴I_13/2 levels. All absorption bands are increase with increasing content of Er³⁺. The photoluminescence spectra were measured with 980 nm light pumped by flash lamp. The spectra trends to increase with increasing concentration of the dopant.

Abstract: Lutetuim calcium silico borates (LuCaSiB) glasses doped with Nd³⁺ ions with molar composition of Lu₂O₃-CaO-SiO₂-B₂O₃-Nd₂O₃ have been prepared by conventional melt quenching technique. Their properties have been evaluated throughout the density, refractive index, absorption and emission measurements. The density, molar volume and refractive index increase with increasing Nd₂O₃ concentration. The optical absorption spectra show twelve bands in visible and near infrared regions. The luminescence spectra exhibit three emission bands were observed at 900, 1072 and 1341 nm corresponding to ⁴F_3/2 → ⁴I_9/2, ⁴I_11/2 and ⁴I_13/2 transition respectively.