New gadolinium based glasses for gamma-rays shielding materials

Kaewjang, S.,Maghanemi, U.,Kothan, S.,Kim, H.J.,Limkitjaroenporn, P.,Kaewkhao, J. North-Holland Pub. Co 2014 Nuclear engineering and design Vol.280 No.-

In this work, Gd<SUB>2</SUB>O<SUB>3</SUB> based glasses in compositions (80-x)B<SUB>2</SUB>O<SUB>3</SUB>-10SiO<SUB>2</SUB>-10CaO-xGd<SUB>2</SUB>O<SUB>3</SUB> (where x=15, 20, 25, 30 and 35mol%) have been fabricated and investigated for their radiation shielding, physical and optical properties. The density of the glass was found to increase with the increasing of Gd<SUB>2</SUB>O<SUB>3</SUB> concentration. The experimental values of mass attenuation coefficients (μ<SUB>m</SUB>), effective atomic number (Z<SUB>eff</SUB>) and effective electron densities (N<SUB>e</SUB>) of the glasses were found to increase with the increasing of Gd<SUB>2</SUB>O<SUB>3</SUB> concentration and also with the decreasing of photon energy from 223 to 662keV. The glasses of all Gd<SUB>2</SUB>O<SUB>3</SUB> compositions studied have been shown with lower HVL values in comparison to an X-rays shielding window, ordinary concrete and commercial window; indicating their potential as radiation shielding materials with Pb-free advantage. Optical spectra of the glasses in the present study had been shown with light transparency; an advantage when used as radiation shielding materials.

Luminescence characteristics of Dy3+ doped Gd2O3-CaO-SiO2-B2O3 scintillating glasses

Kaewkhao, J.,Wantana, N.,Kaewjaeng, S.,Kothan, S.,Kim, H.J. Elsevier 2016 Journal of rare earths Vol.34 No.6

<P>Glasses were prepared from the compositions of 25Gd(2)O(3)-10CaO-10SiO(2)-(55-x)B2O3-xDy(2)O(3) (where x is 0.0 mol.%-1.0 mol.%) by the conventional melt-quenching technique at 1400 degrees C. The results demonstrated the increase in the glass density with respect to the increase in the doping concentrations of Dy2O3. Nine absorption bands were observed. The emission spectra of the developed glass showed two strong peaks at 577 nm (F-4(9/2)-> H-6(13/2)) and 482 nm (F-4(9/2)-> 6H(15/2)). The highest emission intensity was observed from the developed glass prepared at 0.4 mol.% of Dy2O3, as the efficient energy transfer took place from Gd3+ to Dy3+. From the X-ray induced optical luminescence, the emission spectra were identical to those from PL measurements, but with the highest intensity observed from the glass quenched at 0.45 mol.% of Dy2O3. Finally, the integral scintillation efficiency of the developed glass was determined at 27% of that of the commercially available BGO crystal.</P>

Optical properties in the visible luminescence of SiO2:B2O3:CaO:GdF3 glass scintillators containing CeF3

Park, J. M.,Kim, H. J.,Karki, Sujita,Kaewkhao, J.,Damdee, B.,Kothan, S.,Kaewjaeng, S. 한국물리학회 2017 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.

<P>CeF3-doped silicaborate-calcium-gadolinium glass scintillators, with the formula 10SiO(2):(55-x)B2O3:10CaO:25GdF(3):xCeF(3), were fabricated by the melt-quenching technique. The doping concentration of the CeF3 was from 0.00 mol% to 0.20 mol%. The optical properties of the CeF3 doped glass scintillators were studied by using various radiation sources. The transition state of the CeF3-doped glass scintillators studied by using the absorption and photo-luminescence spectrum results. The X-ray, photo, proton and laser-induced luminescence spectra were also studied to understand the luminescence mechanism under various conditions. To understand the temperature dependence, the laser-induced luminescence and the decay component of the CeF3-doped glass scintillator were studied while the temperature was varied from 300 K to 10 K. The emission wavelength spectrum showed from 350 nm to 55 nm under various radiation sources. Also the CeF3-doped glass scintillator have one decay component as 34 ns at room temperature.</P>

Investigations of optical and luminescence features of Sm³⁺ doped Li₂O-MO-B₂O₃ (M =Mg/Ca/Sr/Ba) glasses mixed with different modifier oxides as an orange light emitting phosphor for WLED's

Kirdsiri, K.,Raja Ramakrishna, R.,Damdee, B.,Kim, H.J.,Kaewjaeng, S.,Kothan, S.,Kaewkhao, J. Elsevier 2018 JOURNAL OF ALLOYS AND COMPOUNDS Vol.749 No.-

<P><B>Abstract</B></P> <P>The glass composition of 50Li<SUB>2</SUB>O-20MO-29.7B<SUB>2</SUB>O<SUB>3</SUB>-0.3Sm<SUB>2</SUB>O<SUB>3</SUB> (M = Mg/Ca/Sr/Ba), has been synthesized by the conventional melt quench technique. Density measurements were studied and shows large for LBaBSm glass sample (2.9049 g/cm<SUP>3</SUP>) than any other alkali species (Mg/Ca/Sr). Variation in density is due to the ionic radii of the alkali ion species (M = Mg/Ca/Sr/Ba). Optical absorption spectra of Sm<SUP>3+</SUP> doped LMgB, LCaB, LSrB and LBaB glass systems were studied and shows very intense peaks at NIR region. The emission and excitation spectra of these glasses were studied and emission spectra shows green, yellow and reddish - orange emission bands at 563, 600, 646 and 706 nm. Judd–Ofelt (JO) intensity analysis had been performed and JO parameters were estimated for 0.3 mol.% Sm<SUB>2</SUB>O<SUB>3</SUB> doped 50Li<SUB>2</SUB>O-20MO-29.7B<SUB>2</SUB>O<SUB>3</SUB> (M = Mg/Ca/Sr/Ba) glasses. Radiative properties such as transition probabilities, stimulated emission cross-sections and branching ratios were estimated by using JO parameters and luminescence spectra. The decay curves of these glasses exhibit single exponential nature. The CCT values obtained from CIE for these glass samples shows 1663 K for indicating orange emission under 403 nm excitation wavelength.</P> <P><B>Highlights</B></P> <P> <UL> <LI> J-O parameters of Li2O-MO-B2O3 (M = Mg/Ca/Sr/Ba) glass doped Sm<SUP>3+</SUP> studied. </LI> <LI> LBaBSm0.3 glass show more asymmetry around Sm<SUP>3+</SUP> ion than other transition ions. </LI> <LI> LBaBSm0.3 glass emit bright reddish-orange luminescence at 403 nm excitation. </LI> <LI> The CCT values obtained for glass samples around 1663 K in orange emission. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>UV–Vis–NIR spectra of LMOBSm0.3 (M = Mg, Ca, Sr, Ba) samples.</P> <P>[DISPLAY OMISSION]</P>

Energy transfer based emission analysis of Eu³⁺ doped Gd₂O₃-CaO-SiO₂-B₂O₃ glasses for laser and X-rays detection material applications

Wantana, N.,Kaewnuam, E.,Damdee, B.,Kaewjaeng, S.,Kothan, S.,Kim, H.J.,Kaewkhao, J. Elsevier 2018 Journal of luminescence Vol.194 No.-

<P><B>Abstract</B></P> <P>The Eu<SUP>3+</SUP>-doped CaO-Gd<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB>-B<SUB>2</SUB>O<SUB>3</SUB> glasses were prepared to study photoluminescence, lasing potential and scintillation properties. Glasses absorb photons in ultraviolet, visible light and near infrared regions and are assigned to the energy transitions of Gd<SUP>3+</SUP> and Eu<SUP>3+</SUP>. Ultraviolet with 275nm can generate the strong red emission with 614nm via energy transfer form Gd<SUP>3+</SUP> to Eu<SUP>3+</SUP>. X-ray scintillation study exhibits strong emission pattern due to Gd-Eu energy transfer. The optimum concentrations of Eu<SUP>3+</SUP> ion in this glass is 0.30mol% as it results maximum emission intensity. The fluorescence lifetime of the <SUP>5</SUP>D<SUB>0</SUB> level decreases from 1.763 to 1.726ms when concentration increased from 0.05 to 0.40mol%. From Judd-Ofelt analysis, this glass exhibit high potential for using as laser medium for red laser device with high lasing power and energy extraction ratio. Moreover, this glass performs the integral scintillation efficiency as 13% compared with BGO.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Influence of Er³⁺ ion concentration on optical and photoluminescence properties of Er³⁺-doped gadolinium-calcium silica borate glasses

Kesavulu, C.R.,Kim, H.J.,Lee, S.W.,Kaewkhao, J.,Wantana, N.,Kothan, S.,Kaewjaeng, S. Elsevier Sequoia 2016 JOURNAL OF ALLOYS AND COMPOUNDS Vol.683 No.-

The Er<SUP>3+</SUP>-doped gadolinium calcium silica borate glasses of composition (55-x) B<SUB>2</SUB>O<SUB>3</SUB> - 10 SiO<SUB>2</SUB> - 25 Gd<SUB>2</SUB>O<SUB>3</SUB> - 10 CaO - x Er<SUB>2</SUB>O<SUB>3</SUB>, where x = 0.0, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %, have been prepared by conventional melt quenching technique and are characterized through optical absorption, visible and near-infrared (NIR) emission spectra and decay time measurements. Judd-Ofelt (JO) intensity parameters (Ω<SUB>λ</SUB>, λ = 2, 4 and 6) have been derived from the absorption spectrum of 0.5 mol % Er<SUB>2</SUB>O<SUB>3</SUB> doped glass and in turn are used to calculate radiative properties for the important luminescent levels of Er<SUP>3+</SUP> ions. The studied glasses show intense and broad green (550 nm) and red (591 nm) visible emissions under at 379 nm excitation. Upon excitation at 980 nm laser diode, an intense 1.53 μm NIR emission has been observed with the maximum full width at half maximum (FWHM) and its value is found to be 106 nm for 2.5 mol % Er<SUP>3+</SUP>-doped gadolinium calcium silica borate glasses. This broad luminescence locates in the region of 1420-1635 nm and covers the S, C and L bands. The decay curves of the <SUP>4</SUP>I<SUB>13/2</SUB> level exhibit exponential nature for all the concentrations. The lifetime of the <SUP>4</SUP>I<SUB>13/2</SUB> level has found to be decrease from 1.46 to 1.35 ms with increase of Er<SUP>3+</SUP> ion concentration. Hence, these results clearly indicate that present glasses are suitable for efficient short and conventional-length optical amplifiers and tunable lasers.

Spectroscopic investigations of Nd³⁺ doped gadolinium calcium silica borate glasses for the NIR emission at 1059 nm

Kesavulu, C.R.,Kim, H.J.,Lee, S.W.,Kaewkhao, J.,Wantana, N.,Kaewnuam, E.,Kothan, S.,Kaewjaeng, S. Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.695 No.-

<P><B>Abstract</B></P> <P>The Nd<SUP>3+</SUP>-doped gadolinium calcium silica borate (BSGdCaNd) glasses of composition (55-x) B<SUB>2</SUB>O<SUB>3</SUB> - 10 SiO<SUB>2</SUB> - 25 Gd<SUB>2</SUB>O<SUB>3</SUB> -10 CaO -x Nd<SUB>2</SUB>O<SUB>3</SUB>, where x = 0.0, 0.05, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %, have been prepared by conventional melt quenching technique and are characterized through structural, thermal, absorption, emission and decay time measurements. Based on the Judd-Ofelt intensity parameters and radiative properties were determined from the absorption spectrum. The emission spectra recorded for BSGdCaNd glasses gives three emission transitions <SUP>4</SUP>F<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>9/2</SUB> (903 nm), <SUP>4</SUP>F<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>11/2</SUB> (1059 nm) and <SUP>4</SUP>F<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>13/2</SUB> (1334 nm) for which effective bandwidths (Δλ<SUB>eff</SUB>) and stimulated emission cross-section (σ(λp)) are evaluated. Branching ratios (β<SUB>R</SUB>) measured for BSGdCaNd0.5 glass show that <SUP>4</SUP>F<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>11/2</SUB> transition is quite suitable for lasing applications. The intensity of emission spectra increases with increase in the concentration of Nd<SUP>3+</SUP> ion up to 1.0 mol% and beyond that concentration, quenching is observed. The decay from <SUP>4</SUP>F<SUB>3/2</SUB> level is found to be non-exponential nature for concentrations of Nd<SUP>3+</SUP> ions. The non-exponential curve has been fitted to the Inokuti-Hirayama model to understand the nature of energy transfer process. Hence, the high emission cross-section (1.39 × 10<SUP>−20</SUP> cm<SUP>2</SUP>), branching ratio (0.58) and long lifetime (342 μs) indicate that the BSGdCaNd0.5 glass system could be considered as a good candidate for strong NIR lasers at 1059 nm.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nd<SUP>3+</SUP>-doped gadolinium calcium silica borate glasses were prepared and characterized. </LI> <LI> Spectroscopic parameters were evaluated using Judd-Ofelt theory. </LI> <LI> Optical properties have been evaluated and compared to other host matrices. </LI> <LI> Strong NIR emission at 1059 nm (<SUP>4</SUP>F<SUB>3/2</SUB> → <SUP>4</SUP>I<SUB>11/2</SUB>) has been found for Nd<SUP>3+</SUP> ion in BSGdCaNd glasses. </LI> <LI> BSGdCaNd0.5 glass system could be considered as a good candidate for strong NIR lasers at 1059 nm. </LI> </UL> </P>