• 제목/요약/키워드: Thulium

검색결과 32건 처리시간 0.03초

Effect of rare earth dopants on the radiation shielding properties of barium tellurite glasses

  • Vani, P.;Vinitha, G.;Sayyed, M.I.;AlShammari, Maha M.;Manikandan, N.
    • Nuclear Engineering and Technology
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    • 제53권12호
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    • pp.4106-4113
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    • 2021

  • Rare earth doped barium tellurite glasses were synthesised and explored for their radiation shielding applications. All the samples showed good thermal stability with values varying between 101 ℃ and 135 ℃ based on dopants. Structural properties showed the dominance of matrix elements compared to rare earth dopants in forming the bridging and non-bridging atoms in the network. Bandgap values varied between 3.30 and 4.05 eV which was found to be monotonic with respective rare earth dopants indicating their modification effect in the network. Various radiation shielding parameters like linear attenuation coefficient, mean free path and half value layer were calculated and each showed the effect of doping. For all samples, LAC values decreased with increase in energy and is attributed to photoelectric mechanism. Thulium doped glasses showed the highest value of 1.18 cm-1 at 0.245 MeV for 2 mol.% doping, which decreased in the order of erbium, holmium and the base barium tellurite glass, while half value layer and mean free paths showed an opposite trend with least value for 2 mol.% thulium indicating that thulium doped samples are better attenuators compared to undoped and other rare earth doped samples. Studies indicate an increased level of thulium doping in barium tellurite glasses can lead to efficient shielding materials for high energy radiation.

  • https://doi.org/10.1016/j.net.2021.06.009 인용 PDF KSCI

툴륨이 첨가된 플루오르 계열의 광섬유 증폭기의 1.47$\mu\textrm{m}$ 증폭 대역에 대한 모델링과 분석에 대한 연구 (Theoretical modeling and analysis of thulium doped fluoride fiber amplifier at 1.47 $\mu\textrm{m}$ band amplification)

  • 이원재;민범기;박재형;박남규
    • 한국광학회지
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    • 제11권3호
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    • pp.171-178
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    • 2000

  • 본 논문에서는 $1.47mu$m 증폭대역을 구현하는 툴륨이 첨가된 플루오르 고아섬유 증폭기(Thulium doped fiuoride fiber amplifier : TDFFA)를 수치 해석적 방법으로 모델링하였다. 본 모델은 상위변환(unconvenverison) 펌핑 방식을 도입하였고, $0.8\mu$m, $1.4\mu$m, $ 1.9\mu$m, $2.3 \mu$m 등의 다양한 전이 대역이 존재하는 Tm3+ 이온을 모델링하기 위하여 6개의 에너지 준위에 대한 비율식과 관계된 전이과정들을 고려하는 전파식을 사용하였고 트랜스버스 모드와 파워의 전방과 후방 전파를 고려하였다. 본 모델은 쥬드-오펠트(J-O) 이론, 에너지 캡 법칙, 맥콤보 관계 등을 이용하여 구한 TDF의 분광 파라미터들을 사용하였다. 시뮬레이션 결과는 이득과 잡음지수 등이 기존의 실험 결과와 비교하여 잘 부화된 결과를 보인다.

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Effect of Thulium Doping on Luminescence Properties of $YAIO_3$and $YTa_7O_{19}$

  • Hojin Ryu;Park, Hee-Dong
    • The Korean Journal of Ceramics
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    • 제3권1호
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    • pp.43-46
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    • 1997

  • Thulium (Tm) has been incorporated into $YAlO_3$ and $YTa_7O_{19}$ host materials to obtain blue phosphors. $Tm^{3+}$-doped $YAlO_3$ and $YTa_7O_{19}$ phosphors were prepared by the conventional solid state reaction method. According to the results of excitation and emission spectra measured at room temperature, the blue emission intensity of $Tm^{3+}$-doped $YTa_7O_{19}$, peaking at 455 nm was much higher than that of $Tm^{3+}-doped\; YAlO_34, peaking at 458 nm. The maximum of relative intensity of $Tm^{3+}-doped\; YAlO_3\; and\; YTa_7O_{19}$ was obtained at the doping concentration of 0.016 and 0.120 mol% $Tm^{3+}$, respectively. These emission spectra revealed the concentration quenching effect.

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Effects of Dysprosium and Thulium addition on microstructure and electric properties of co-doped $BaTiO_3$ for MLCCs

  • Kim, Do-Wan;Kim, Jin-Seong;Noh, Tai-Min;Kang, Do-Won;Kim, Jeong-Wook;Lee, Hee-Soo
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2010년도 춘계학술발표대회
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    • pp.48.2-48.2
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    • 2010

  • The effect of additives as rare-earth in dielectric materials has been studied to meet the development trend in electronics on the miniaturization with increasing the capacitance of MLCCs (multi-layered ceramic capacitors). It was reported that the addition of rare-earth oxides in dielectrics would contribute to enhance dielectric properties and high temperature stability. Especially, dysprosium and thulium are well known to the representative elements functioned as selective substitution in barium titanate with perovskite structure. The effects of these additives on microstructure and electric properties were studied. The 0.8 mol% Dy doped $BaTiO_3$ and the 1.0 mol% Tm doped $BaTiO_3$ had the highest electric properties as optimized composition, respectively. According to the increase of rare-earth contents, the growth of abnormal grains was suppressed and pyrochlore phase was formed in more than solubility limits. Furthermore, the effect of two rare-earth elements co-doped $BaTiO_3$ on the dielectric properties and insulation resistance was investigated with different concentration. The dielectric specimens with $BaTiO_3-Dy_2O_3-Tm2O_3$ system were prepared by design of experiment for improving the electric properties and sintered at $1320^{\circ}C$ for 2h in a reducing atmosphere. The dielectric properties were evaluated from -55 to $125^{\circ}C$ (at $1KHz{\pm}10%$ and $1.0{\pm}0.2V$) and the insulation resistance was examined at 16V for 2 min. The morphology and crystallinity of the specimens were determined by microstructural and phase analysis.

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