Thermoluminescence in fluorapatite doped with Eu2O3 and PbO

Thermoluminescence (TL) of fluorapatite Ca5(PO4)3F doped with Eu2O3 has been investigated for UV and X ray irradiation. Two TL glow peaks for the Eu2O3 doped sample appeared in the temperature regions about (1) 353 to 380 K and (2) 508 to 510 K, when heated at rate of 20 K.min(-1) after UV or X ray irradiation at room temperature. It has been found that the peak 2 (508 to 510 K) intensity of the samples doubly doped with Eu2O3 and PbO became strong compared with that doped with only Eu or Pb ions. From the TL spectra for the Ca5(PO4)3F doped activators, it is concluded that the TL of Eu2+ ions is sensitised by the existence of Pb2+ ions. On the other hand, the TL of Eu3+ ions is not intensified by addition of PbO. The TL emission may be due to the recombination reaction: Eu3+ + e-->Eu2+*-->Eu2+ + hv. EU2+ + hole --> Eu3+* --> Eu3+ + hv. The 510 K TL peak may be also being suitable for use as a dosemeter.     

Thermoluminescent spectra of rare earth doped MgB4O7 dosemeters

This paper presents X ray excited TL spectra of magnesium borate doped with either single rare earth ions Dy or Tm, or co-doped with Dy/Tm, Tm/Mn or Dy/Tb. Intrinsic emission from the host material is in the UV/blue region at approximately 375 nm, with a tail extending to 200 nm. The main dosimetric peak is detected at approximately 180 degrees C but slight differences are noted between the glow peak maxima from the different rare earth ions and there were changes following thermal treatments. The results are discussed according to the interaction between trapping and rare earth sites.     

Thermoluminescence response of K2YF5:Tb3+ crystals to photon radiation fields

This investigation has been performed to test the feasibility of using K2YF5:Tb3+ crystals as thermoluminescence dosemeters (TLD). K2YF5 single crystals doped with 0.2, 10.0 and 50.0 at.% of trivalent optically active Tb3+ ions as well as K2TbF5 and undoped K2YF5 crystals have been synthesized under hydrothermal conditions. Polished crystal platelets with thickness of about 1 mm have been irradiated with X and gamma rays in order to study thermoluminescent (TL) sensitivity as well as dose and energy response in terms of the Tb3+ concentration in K2YF5. Within this concentration series, K2YF5 crystals doped with 10.0 at.% Tb3+ have been found to have maximum TL response due to a broad asymmetric TL glow peak at 269 degrees C with good linearity of dose response and reproducibility of dose measurements. After deconvolution, the main dosimetric peak has been revealed to be composed of two individual peaks, both with linear TL response behaviour, centered at 210 and 269 degrees C. As it has been proved, the linear TL signal coefficient for K2Y0.9Tb0.1F5 is almost 10 times greater than that for commercial TLD-100 (LiF:Mg,Ti), irradiated with a 137Cs gamma radiation source at the same conditions. The reported results indicate that K2YF5 crystals doped with Tb3+ have potential as promising materials for radiation dosemeters.     

Effect of structure, particle size and relative concentration of Eu(3+) and Tb(3+) ions on the luminescence properties of Eu(3+) co-doped Y(2)O(3):Tb nanoparticles

Eu(3+) co-doped Y(2)O(3):Tb nanoparticles were prepared by the combustion method and characterized for their structural and luminescence properties as a function of annealing temperatures and relative concentration of Eu(3+) and Tb(3+) ions. For Y(2)O(3):Eu,Tb nanoparticles annealed at 600 and 1200?°C, variation in the relative intensity of excitation transitions between the (7)F(6) ground state and low spin and high spin 4f(7)5d(1) excited states of Tb(3+) is explained due to the combined effect of distortion around Y(3+)/Tb(3+) in YO(6)/TbO(6) polyhedra and the size of the nanoparticles. Increase in relative intensity of the 285?nm peak (spin-allowed transition denoted as peak B) with respect to the 310?nm peak (spin-forbidden transition denoted as peak A) with decrease of Tb(3+) concentration in the Y(2)O(3):Eu,Tb nanoparticles heated at 1200?°C is explained based on two competing effects, namely energy transfer from Tb(3+) to Eu(3+) ions and quenching among the Tb(3+) ions. Back energy transfer from Tb(3+) to Eu(3+) in these nanoparticles is found to be very poor.     

Tb3+-Yb3+共掺氟氧化物微晶玻璃的发光特性及其外量子效率的评价

本研究制备了Tb3+-Yb3+共掺杂含CaF2纳米晶相的氟氧化物透明微晶玻璃,并通过XRD验证了CaF2纳米晶的形成。基于Tb3+对Yb3+的协同能量传递,通过激发Tb3+∶5D4能级可观察到由Yb3+∶2F5/2→2F7/2跃迁引起的950~1100nm近红外发射。利用积分球测试系统评价了Yb3+在玻璃及微晶玻璃体系中的外量子效率,数据表明经过热处理后Yb3+的外量子效率有明显的增加,这是由于在微晶玻璃体系中掺杂的Tb3+离子和Yb3+离子富集在具有低声子能量的CaF2晶相从而获得了更有效的能量传递而引起的。同时利用Tb3+荧光寿命计算获得了材料的内量子效率,其值远大于外量子效率,这是由计算过程中的诸多近似所导致。     

Ba2+共掺杂YPO4∶Tb3+荧光材料的水热合成与荧光性能

采用水热法合成Ba~(2+)共掺杂YPO4∶Tb~(3+)荧光材料,并通过X射线衍射(XRD)、扫描电子显微镜(SEM)和荧光分光光度计等研究了合成样品的物相组成和荧光性能,并分析了Ba~(2+)掺杂量和反应体系pH值等对合成样品的物相结构及荧光性能的影响。结果表明,反应体系pH值和Ba~(2+)掺杂量直接影响所制备样品的结构与性能。少量Ba~(2+)(≤10%,原子分数,下同)共掺杂YPO4∶1%Tb~(3+)样品均为纯相四方晶系磷钇矿结构晶体,过量Ba~(2+)掺杂导致Ba_3(PO_4)_2杂质相的出现;pH值为6的水热环境下可获得高结晶度的单一相Ba~(2+)、Tb~(3+)共掺杂YPO4样品。激发和发射光谱测试结果表明,所制备的YPO4∶1%Tb~(3+),x%Ba~(2+)样品可被225nm的紫外光有效地激发而发射出强烈的Tb~(3+)特征的黄绿色光。一定量的Ba~(2+)共掺杂可以有效地提高YPO4∶1%Tb~(3+)样品的荧光性能,但过量(高于10%)的Ba~(2+)掺杂又会导致Tb~(3+)的荧光猝灭现象出现,最佳的Ba~(2+)共掺杂量为10%。所制备的YPO4∶1%Tb~(3+),10%Ba~(2+)样品在225nm紫外光激发下位于545nm处的发射带强度是YPO4∶1%Tb~(3+)样品的1.8倍。     

Phototransferred thermoluminescence for use in UVB dosimetry

Results are reported of a study of phototransferred thermoluminescence (PTTL) as a potential method for ultraviolet (UV) radiation dosimetry using several different TL materials. The materials studied in depth include Al2O3:C, CaF2:Cu, MgO and MgO:Cu. The experimental features discussed in this paper include the PTTL response as a function of exposure time at 307 nm and the PTTL wavelength dependence over the range 250-450 nm, using a fixed photon flux at the sample. The study confirms the attractive properties of Al2O3:C as a UV dosimetry material, while CaF2:Cu is shown to have potential as a UVC dosemeter.     

Optically and thermally stimulated luminescence characteristics of MgO:Tb3+

In this paper main optically stimulated luminescence (OSL) and thermoluminescence (TL) characteristics are presented of a newly synthesised material MgO doped with terbium (Tb) developed at the Institute of Nuclear Science, Vinca. A thermally stimulated emission spectrum showed the characteristic lines of Tb3+ in a wide range of wavelengths. The TL sensitivity of the main TL glow peak at 315 degrees C is 1.7 times higher than the TL of Al2O3:C. The highest OSL sensitivity was obtained under green lamp (500-570 nm) stimulation. The fast component in the OSL decay curve is 2.4 times faster than Al2O3:C. The OSL signal is linear with dose up to 10 Gy. The lower limit of detection was found to be 100 microGy. These first results show that the newly synthesised material has some promising properties for the application in radiation dosimetry.     

Zn、Pr共掺In2O3陶瓷材料的高温热电传输性能

利用放电等离子SPS烧结工艺制备得到Zn、Pr共掺的In2O3多晶陶瓷材料。通过研究材料的热电传输性能和微观结构,发现共掺工艺对SPS烧结的In2O3陶瓷材料的传输性能有着显著的影响,其结构为多孔结构。低浓度共掺的样品在测试温度范围内能够得到较高的电导率(约100S/m)和热电势(约200μV/K)。其中试样In1.92(Pr,Zn)0.08O3的热导率973K最低为2.5W/(m.K),该样品可获得最高的热电功率因子3.5×10-4 W/(m.K2),对应其热电优值0.10。其性能表明利用放电等离子SPS烧结工艺制备的In2O3基陶瓷作为n型高温热电材料具有很好的潜力。     

Thermoluminescence and lyoluminescence in γ-ray irradiated and Ce3+-doped YCa4O(BO3)3 phosphors

YCa₄O(BO₃)₃ crystal having various concentration of Ce ions were synthesized by solid-state diffusion technique. XRD pattern of the sample confirmed the formation of the sample. Thermoluminescence (TL) and lyoluminescence (LL) of the γ-ray-irradiated sample were recorded. Two distinct peaks around 160 and 277 °C were observed in TL glow curves. TL intensity increased with increasing dopant concentration up to 2 mol%. A single sharp peak was observed in the LL glow curve of the sample. It was found that both TL and LL increased almost linearly with γ-ray doses up to 1.5 kGy. Photoluminescence (PL) of the sample was recorded to find the role of rare earth ion doped in YCa₄O(BO₃)₃. PL emission spectrum showed two peaks lying very close to each other around 390 nm which are characteristics of 5d → 4f transition of Ce³⁺ ions. When LL of samples was recorded after removing the TL peaks it did not show any emission. This indicates that emission centres responsible for TL are also responsible for LL.     

Preparation and luminescence properties investigation of Eu3+, Tb3+-doped LaNbO4:RE3+ (RE = Eu,Eu/Tb,Tb)

Journal of Materials Science: Materials in Electronics - In this work, doped and co-doped LaNbO4:RE3+ (RE?=?Eu, Eu/Tb, Tb) single crystals were prepared by a unique hydrothermal method...     

A study on the magnetic and photoluminescence properties of Eu(n+) and Sm3+ doped Fe3O4 nanoparticles

In this paper, Eu(n+), Sm3+ doped Fe3O4 nanoparticles were prepared via solvothermal method, in which Ferric chloride is used as the iron source, and anhydrous EuCl3, SmCl3 as doping source. Eu, Sm valence in doped Fe3O4 nanoparticles, and effects of Eu, Sm doping amount on their structure, morphology, magnetic properties and PL properties were discussed. The results show, the Eu ions had doped Fe3O4 nanoparticles in the mixed-valence state, when the Eu and Sm doping amount were increased, the doped Fe3O4 nanoparticles changed from hollow nanospheres into spherical particles, and finally changed into uniform cube-shaped particles with 13 nm in diameter. Moreover, the doping sites for doping ions in doped Fe3O4 nanoparticles were discussed from Rietveld analysis of XRD pattern of the doped Fe3O4 nanoparticles. And the changes of the magnetic and PL properties with the doping amount were further discussed. It was found that higher Sm(3+)-doping amount led to stronger magnetic dipole transitions, while the Eu(n+)-doping amount had little effect on the magnetic dipole transitions, thus resulting in different changes in their saturation magnetization with doping amount.     

ATP/CaF_2∶Ln~(3+)(Ln∶Eu,Tb,Ce/Tb)纳米粒子的制备及其荧光性能

采用两步法制备了三磷酸腺苷二钠(ATP)修饰的ATP/CaF_2∶Ln~(3+)(Ln∶Eu,Tb,Ce/Tb)纳米粒子。采用红外光谱(IR)、X-射线衍射分析(XRD)、透射电子显微镜(TEM)对所合成的纳米粒子进行结构表征,并通过荧光光谱(FS)研究了纳米粒子的荧光性能。结构研究结果表明,ATP成功地包覆在纳米粒子的表面,纳米粒子的晶相为CaF_2的立方结构,ATP/CaF_2∶Eu~(3+)、ATP/CaF_2∶Tb~(3+)、ATP/CaF_2∶Ce~(3+)/Tb~(3+)纳米粒子的平均粒径分别约为14nm、15nm、11nm。荧光性能研究表明,ATP/CaF_2∶Eu~(3+)、ATP/CaF_2∶Tb~(3+)纳米粒子基本不发射稀土离子的特征荧光,而发射出修饰剂ATP的荧光,由于Ce~(3+)对Tb~(3+)的敏化作用,ATP/CaF_2∶Ce~(3+)/Tb~(3+)纳米粒子发射出Tb~(3+)的特征荧光。     

Thermoluminescence response of CaS:Bi nanophosphor exposed to 200 MeV Ag ion beam

A study of the thermoluminescence (TL) parameters has been performed on swift heavy ion exposed Bi³⁺ doped CaS nanophosphors prepared by the chemical co-precipitation method. All the samples have been exposed to 200 MeV Ag⁺¹⁵ ions in a fluence range of 1 × 10¹²–1 × 10¹³ ions/cm². The prominent TL glow peak at 403 K (observed for the γ-irradiated sample) appeared at the same position in the 200 MeV Ag⁺¹⁵ ion beam irradiated samples, while the other peak at 466 K disappeared and the broad peak normally measured at 534 K split into two peaks at 535 K and 582 K for the Ag⁺¹⁵ ion beam irradiated samples. The effect of different Bi³⁺ concentration has been investigated and it was found that the maximum TL intensity was measured for the 0.08 mol% sample. The effect of different heating rates on the TL response has also been determined. The trapping parameters (i.e. activation energy, frequency factor, order of kinetic) of all the individual peaks of the glow curves have been analysed by using Chen’s formulae. The low fading and linear TL response in the range of 1 × 10¹²–1 × 10¹³ ions/cm² will be helpful to explore the potential use of this material for heavy ion dosimetry.     

UV-VUV excited luminescence of SrBPO5:Sm phosphor prepared in air

The high-resolution luminescent spectrum of divalent samarium excited by 355 nm UV light at 77 K, the VUV excitation spectra, the VUV excited emission spectra and EXAFS at Sm-L₃ edge were reported for samarium doped strontium borophosphate, SrBPO₅:Sm prepared by solid state reaction in air at high temperature. The high-resolution luminescent spectrum showed that the divalent samarium ions occupied the C_2υ lattice sites. The VUV excitation spectra indicated that the sample exhibited absorption bands with the maxima at 129 and 148 nm, respectively. The performance of EXAFS at Sm-L₃ absorption edge suggested that the samarium ions were nine-coordinated and the mean distances of bond SmO were 2.38 Å.     

可见光波段稀土激光晶体的研究进展

可见光激光在数据存储、光通讯、激光显示、激光医疗、激光打印以及科学研究等领域具有非常重要的应用价值。随着蓝光LD泵浦源的商用化, 直接泵浦稀土离子掺杂激光晶体实现可见光激光输出吸引了人们极大的研究兴趣。目前, 可见光稀土离子主要集中在Pr ³⁺、Dy ³⁺、Tb ³⁺和Sm ³⁺等。其中, Pr ³⁺的研究较多, 发光波长涵盖面较广, 发射波段覆盖蓝光、绿光、红光、橙光; Dy ³⁺和Tb ³⁺因为能够发射黄光以填补Pr ³⁺的不足也吸引了广泛的研究; 此外, Sm ³⁺和Eu ³⁺也是典型的可见波段稀土发光离子。本文综述了近几年可见波段稀土离子掺杂激光晶体的研究现状, 主要以Pr ³⁺、Dy ³⁺、Tb ³⁺和Sm ³⁺掺杂YAlO₃ (YAP)、Mg : SrAl₁₂O₁₉ (SRA)等晶体为研究对象, 总结了一套适合Pr ³⁺掺杂材料的判据, 对晶体生长、结构、热学性能、偏振光谱性能和激光性能进行了系统的研究。     

Sm3+/Ce3+/Tb3+共掺CaO-B2O3-SiO2发光玻璃的制备及发光性能研究

采用高温熔融法制备了Sm3+/Ce3+/Tb3+共掺杂的CaO-B2O3-SiO2发光玻璃材料,并用荧光分光光度计和CIE色度坐标对其发光性能进行了研究。发射光谱表明,在374nm激发下,Sm3+/Ce3+/Tb3+共掺杂CaO-B2O3-SiO2发光玻璃的发射光谱中同时观测到了红橙光、蓝光和绿光的发射带,这些发射带的混合实现了白光发射。此外,在Sm2O3和Tb4O7含量不变的情况下,随着CeO2含量的减小,Sm3+/Ce3+/Tb3+共掺杂发光玻璃的发光颜色在白光区逐渐由蓝光区附近过渡到黄光区附近。     

Dispersion of luminescent nanoparticles in different derivatives of poly(ethyl methacrylate)

Gd2O3:Tb(5%) nanoparticles were prepared via the polyol route and dispersed without any stabilizer in several ethyl methacrylate derivatives matrices such as poly(ethyl methacrylate), poly(2-methoxyethyl methacrylate) and poly(2-hydroxyethyl methacrylate) (PHEMA). Nanocomposites were obtained via free-radical polymerization of methacrylic monomers with ethylene glycol dimethacrylate as crosslinker and colloidal solution of Gd2O3:Tb(5%) nanoparticles. Best results are obtained with PHEMA in which the dispersed Gd2O3:Tb(5%) nanoparticles are spherical with a mean diameter of 15 nm, as measured by TEM. The obtained solid Gd2O3:Tb(5%)/PHEMA nanocomposites are highly transparent (in the visible spectral range) and exhibit characteristic photoluminescence of Tb3+ 5D4-7F(J) (J = 6-3), with 5D4-7F5 strong green emission at 536 nm upon UV excitation. The nanoparticles and nanocomposites have been well characterized by high-resolution transmission electron microscope (TEM), UV/Vis transmission spectra, photoluminescence excitation, and emission spectra.     

Study on luminescence behavior of BaAl12O19:Tb, Eu

BaAl12O19:Tb, Eu phosphors were prepared by sol-gel technique. The luminescence properties and the energy transfer between Eu2+ and Tb3+ were investigated. For BaAll2O19:Tb phosphor, the strongest excitation peak and emission peak produced from Tb3+ transition of 5D4-7F5 were at 240 nm and at 550 nm respectively, while the peak shape was narrow and peak intensity was large. The Eu2+ added in the BaAl12O19:Tb induced energy transfer to Tb3+ and different color luminescence from blue (400 nm) to green (570 nm) was obtained by changing the ratio of Tb3+/Eu2+ with excitation at 240 nm.     

具可变价态稀土氧化物对Mg2Ni合金储氢性能的催化作用

采用球磨法制备Mg2Ni-Ni-5%RExOy(CeO2,Nd2O3,Tb4O7)复合材料。通过XRD,SEM,面扫描能谱分析,电化学及动力学测试系统研究材料的组织及储氢性能。结果表明:添加稀土氧化物后复合材料的结晶程度降低,稀土氧化物催化剂在合金表面分布均匀。复合材料的最大放电容量明显提高,含Tb4O7样品室温下最大放电容量达871mAh·g-1,且具有较高循环稳定性。CeO2及Tb4O7催化剂可有效提高合金电极表面电荷转移能力,增大氢原子在合金内部的传输速率。稀土氧化物催化剂还可提高复合材料的气态吸氢容量,其中含Tb4O7样品的吸氢量最高,在250℃时吸氢量达到2.02%(质量分数),但在较低温度时吸氢速率稍慢。稀土氧化物的催化作用主要与稀土离子的变价特性有关,离子的易变价性越强,则催化活性越高。催化活性由大到小的顺序为Tb4O7>CeO2>Nd2O3。