Papers by Keyword: Thulium

Abstract: Effects of gamma radiation on the elastic properties of {[(TeO₂)_0.7(B₂O₃)_0.3]_0.7[ZnO]_0.3}_0.99{Tm₂O₃}_0.01 (thulium doped zinc borotellurite glass) were investigated. Glass samples were prepared using the melt-quenching technique. Density and ultrasonic velocity of glasses before and after irradiation process were measured using Electronic Densimeter MD-300S and Ritec Ram-5000 Snap System, respectively. Next, elastic moduli and Poisson’s ratio of the glasses were calculated. Atomic ring size of the glass network was also calculated to support the attained results. Results show that density varied after radiation and maximised at 20 kGy. This is attributed to the breaking and rearrangement of chemical bonding in the glass network due to radiation. Furthermore, all elastic parameters exhibited an increasing trend that indicated the strengthening of the glass samples as well as increment of its rigidity. Besides that, atomic ring size was found to decrease as radiation dose increased. This indicate that compaction of glass network took place as the samples were exposed to gamma rays which in turn contributed to the elevation of elastic moduli of the prepared glass.

Abstract: In this paper, MgSO₄:Dy,MgSO₄:Tm and MgSO₄:Mn phosphors are prepare by high temperature solid state reaction. The MgSO₄:Dy or MgSO₄:Tm powder are mixed and sintered with MgSO₄:Mn respectively to obtain the co-doped MgSO₄:Dy,Mn and MgSO₄:Tm,Mn phosphors. The 3-dimensional thermoluminescence spectra of these two phosphors under different sintering temperature are measured.Results show that when the sintering temperature is below 800°C, Dy, Tm and Mn ions emissions are independent. However, when the sintering temperature was over 800°C, the emission peak of Mn becomes weaker, and so do the low temperature peaks of Dy and Tm, while the high temperature peaks of Dy and Tm become stronger. This indicated that the defect complex structure in the formation of the thermoluminescence material depends on the sintering temperature. As the sintering temperature rises, more and more Mn ions combine with the rare earth ions. Therefore, the luminescence process of the energy transfer of Mn ions to the rare earth ions can be observed and the suppression to low temperature peaks of Tm and Dy, and also shown in spectra.

Abstract: Absorption and fluorescence spectra in the range from 350 to 1750 nm of several Tm3+- doped optical performs (rods) for optical fiber drawing were measured. Silica-based matrices of Al2O3-GeO2-P2O5-Sb2O3-SiO2 composition doped with several thousands ppm of Tm3+ were characterized. The preforms were fabricated by the Modified Chemical Vapor Deposition and by the solution doping methods. A new method, Genetic Algorithm SPEctra Decomposition was adopted for processing of the measured absorption spectra. This decomposition made it possible to calculate the oscillator strengths of Tm3+ absorption levels. Fluorescence bands of Tm3+ at 800 nm or 1640 nm were found in fluorescence spectra measured on the preform samples when excited at 1064 nm only.