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Growth, Luminescence and Scintillation Characterization of Disodium Di-tungstate (Na2W2O7) Crystal Scintillator
摘要： A single crystal of Na2W2O7 was grown by using the conventional Czochralski technique. The crystal structure of the grown sample was veri?ed by using a powder X-ray di?raction (XRD) analysis. The luminescence, as well as scintillation, properties of the crystals were evaluated at room temperature. The emission spectra of the crystal were obtained by irradiating the sample with X-ray and proton sources. The trap level of the grown crystal was studied from 325 K to 500 K, and di?erent kinematic parameters were calculated. The scintillation properties such as; energy resolution, light yield, ?uorescence decay time and α/β ratio of the crystal, were studied by using γ- (662 keV from 137Cs) and α- (5.4 MeV from 241Am) sources. The luminescence and the scintillation results revealed that the Na2W2O7 crystal would be a good material for the dark matter search and for high-energy physics experiment.
关键词： Czochralski technique,Na2W2O7,Dark matter search,Luminescence and scintillation
更新于2025-11-14 15:30:11
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Crystal growth and optical properties of Ca <sub/>3</sub> TaGa <sub/>3</sub> Si <sub/>2</sub> O <sub/>14</sub> single crystals
摘要： Transparent yellowish Ca3TaGa3Si2O14 single crystals were grown in Ar+(0.5–3)% O2 along the Y-axis by the Czochralski technique. The structural perfection of Ca3TaGa3Si2O14 samples was studied by X-ray topography and rocking curve methods. Topograms and rocking curves along the surfaces of the Y- and Z-cuts were studied before and after surface treatments (polishing and etching). Transmittance spectra were measured in the wavelength range of 200–3300 nm. Optical anisotropy was studied along the X- and Z-axes, and dichroism along the X-axis. The dispersions of the refractive index No and speci?c rotation of the polarization plane were determined using spectrophotometric methods.
关键词： optical properties,Czochralski technique,single crystals,Ca3TaGa3Si2O14,X-ray topography
更新于2025-09-23 15:21:01
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On symmetry of rare-earth scandium borate RESc3(BO3)4 (RE = Ce, Nd) laser crystals
摘要： Symmetry, structural features, and point defects in the Czochralski-grown single crystals with the initial compositions CeSc3(BO3)4 (CSB-1.0) and Nd1.25Sc2.75(BO3)4 (NSB-1.25) are studied by the full-profile Rietveld method on synchrotron X-ray powder data. The space group P321 is first established and confirmed for CSB-1.0 and NSB-1.25 crystals, respectively. The features of synchrotron diffraction patterns that distinguish the space group Р321 from the R32 one are given. The site occupancies in both structures are refined and resulted in the stoichiometric composition for CeSc3(BO3)4, which coincides with the nominal composition, and the composition [Nd0.455(1)Sc0.045(39)(1)]Nd0.500(2)Sc3(BO3)4 ((Nd0.955Sc0.045(39))Sc3(BO3)4), which differs from the initial Nd1.25Sc2.75(BO3)4 one, with partial occurrence of Sc ions in one of the trigonal-prismatic sites. An analysis of literature data on single crystals with the general formula RESc3(BO3)4 (RE ? Ce, Pr, Nd) together with the results of present study of powdered single crystals gives reason to exclude a crystallization of these compounds and solid solutions based on them in the space group R32. The correlation between the refined compositions of RESc3(BO3)4 crystals (RE ? La, Ce, Pr, Nd), having a specific space group, and compositions of initial charge is given.
关键词： Crystal structure,Czochralski technique,Optical materials,Point defects,Synchrotron radiation
更新于2025-09-23 15:19:57
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Growth of pure and BFO doped KCl crystals by Czochralski technique and fabrication of microstrip patch antenna for GHz applications
摘要： Large sized pure and 0.1 mol% BiFeO3 (BFO) doped KCl single crystals were grown by Czochralski technique. Structural parameters were confirmed by powder XRD and single crystal XRD. EDX analysis was used to determine the elemental composition of BFO and KCl crystal. Photoluminescence confirmed that BFO acts as defect quenching agent for KCl single crystal which improved its optical transparency. Doping of BFO in KCl single crystal increased its hardness as measured by a Vicker’s microhardness test. The effect of BFO on dielectric constant and dielectric loss of KCl crystal, at various temperature and frequencies was studied. The low dielectric constant viz. 4.5 and 5.8 for pure and BFO doped KCl was helpful in designing and fabricating patch antenna in GHz frequency. As a result of BFO doping, the resonant frequency of microstrip patch antenna can be tuned at 5.40 GHz from 6.01 GHz for the KCl single crystal.
关键词： Czochralski technique,GHz applications,microstrip patch antenna,BiFeO3 (BFO),KCl single crystal
更新于2025-09-10 09:29:36