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Author: search.filters.author.Basavapoornima, ChSubject: search.filters.subject.Radiation shielding

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    Item type:Publication,
    Optical and emission Spectroscopy and radiation shielding properties of Sm3+-Doped P2O5 + BaO + La2O3 glasses
    (2026-01-01)
    Kesavulu, C. R.
    ;
    Masthanaiah, E.
    ;
    Basavapoornima, Ch
    ;
    Depuru, Shobha Rani
    ;
    Pecharapa, Wisanu
    Within lanthanide series, Sm<sup>3+</sup>(4f<sup>5</sup>) ion is relatively very complex electronic structure and similar to Dy<sup>3+</sup>(4f<sup>9</sup>) ion but both ions exhibit visible and infrared emissions. As such, characteristics (structural, thermal, optical, luminescence, etc.) of Sm<sup>3+</sup> ion doped crystals, glass-ceramics, phosphors and glasses have been widely investigated for development of visible photonic devices, scintillators and magnetic components. In this paper, studies carried out so far on physical, structural, luminescence and optical characteristics of Sm<sup>3+</sup>-embedded glasses have been collected, tabulated and re-analysed in a systematic procedure besides our own work on P<inf>2</inf>O<inf>5</inf> + BaO + La<inf>2</inf>O<inf>3</inf> + Sm<inf>2</inf>O<inf>3</inf> (PBaLaSm) glasses. All the quantified properties have also been reviewed besides the labeling of glass compositions in a meaningful way. The properties that are reviewed include, optical energy gap, Judd-Ofelt (JO), radiative, etc. The obtained JO parameters ( × 10<sup>−20</sup> cm<sup>2</sup>) for the present glasses are Ω<inf>2</inf> = 5.57, Ω<inf>4</inf> = 5.22 and Ω<inf>6</inf> = 3.37. In the case of Sm<sup>3+</sup> ion, it has been noticed that the JO analysis found to be not only sensitive to the co-ordination geometry of the surrounded glass composition but also on the number of absorption levels that are used for the JO analysis. Theoretical radiation shielding results for the studied glass found to be better than the RS-253-G18, RS-360, lead and ordinary concrete at 30 and 40 KeV. The decay rates for <sup>4</sup>G<inf>5/2</inf> level of Sm<sup>3+</sup> ions in the PBaLaSm glasses have been measured and are found to exhibit single exponential nature at lower concentration and turns into non-exponential at higher concentrations (≥1.0 mol % Sm<inf>2</inf>O<inf>3</inf>-doped glasses). The experimental lifetimes for <sup>4</sup>G<inf>5/2</inf> level of Sm<sup>3+</sup> ions are found to decrease from 2413, 2383, 2129, 2039, 1299 and 259 μs when concentration increases from 0.01, 0.05, 0.1,0.5, 1.0 and 2.0 mol % due to cross-relaxation energy transfer. The non-exponential decay rates are well-fitted to Inokuti-Hirayama model for S = 6, indicates that the energy transfer is of dipole-dipole type. However, the overall observations outlined in this study for 48 Sm<sup>3+</sup>:glasses may be quite useful for those who are interested in this thrust area to plan and carryout systematic study to get constructive conclusion besides predictive nature.
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    Structural, optical, luminescence spectroscopy and radiation shielding properties of Eu3+:borophosphotellurite glasses
    (2024-10-01)
    Masthanaiah, E.
    ;
    Basavapoornima, Ch
    ;
    Lokanadham, R.
    ;
    Pecharapa, Wisanu
    ;
    Kaewkhao, J.
    Recently much effort is being paid to study the rare earth ions in multi component glass formers as they exhibit high enhancement in the efficiency of luminescence properties. In this direction, the present study focuses on the preparation and analysis of novel glass batches with composition of (in mol %) BPTCZEu: 40B<inf>2</inf>O<inf>3</inf>+20P<inf>2</inf>O<inf>5</inf>+15TeO<inf>2</inf>+ 10CaO+(15−x)ZnO + xEu<inf>2</inf>O<inf>3</inf>, x = 0.1, 0.5, 1.0, 1.5, 2.0 and 2.5. The important spectroscopic techniques such as optical absorption, luminescence, excitation and decay curves are taken to analyse the BPTCZEu glasses. Luminescence spectrum of BPTCZEu comprise of emission from excited (<sup>5</sup>D<inf>0</inf>) to the lower multiplets (<sup>7</sup>F<inf>J</inf> (J = 0−4)), among these, <sup>5</sup>D<inf>0</inf> → <sup>7</sup>F<inf>2</inf> (red luminescence) at 612 nm found to be very intense. Judd−Ofelt characteristics, Ω<inf>2</inf>, Ω<inf>4</inf> and Ω<inf>6</inf>, were derived from different constraints. To know the site symmetry around Eu<sup>3+</sup>, the fluorescence intensity ratio of <sup>5</sup>D<inf>0</inf> → <sup>7</sup>F<inf>2</inf> vs. <sup>5</sup>D<inf>0</inf> → <sup>7</sup>F<inf>1</inf> were analysed. Exciting <sup>7</sup>F<inf>0</inf> → <sup>5</sup>L<inf>6</inf> and monitoring <sup>5</sup>D<inf>0</inf> → <sup>7</sup>F<inf>2</inf>, the lifetime of <sup>5</sup>D<inf>0</inf> level is determined to be 2 ms which is independent of Eu<sup>3+</sup> content. The colour coordinates for all the Eu<sup>3+</sup> concentrations are estimated to fall in the reddish−orange region. Theoretical radiation shielding results showed that substituting Eu<inf>2</inf>O<inf>3</inf> for ZnO in the glasses lowers photon number that can pass via the material, enhancing the glass system's trend to shield high energy radiation. These stimulated results are compared with experimental measurements of mass attenuation coefficient with respect to energy up to 662 KeV using Cs−137 source. All these findings obtained from title glasses are compared and discussed with respect to reported Eu<sup>3+</sup>:glasses and no systematic variation has been noticed either with single, bi− or multi−component glass formers and therefore needs further systematic work to relate Eu−radiation−ligand interaction.