Analysis of the thermoluminescent of borate glass by computerized glow curve deconvolution in kinetic formalism

Borate based phosphor is a suitable material for thermoluminescence dosimetry. Glow curves of β-irradiated pure borate glass has been analyzed by restoring to Computerized Glow Curve Deconvolution (CGCD) technique and evaluate the trapping parameters namely activation energy (E), frequency factor (s) and order of kinetics (b). It is observed that there are stable peaks in the range 110° to 150°C even to various extent of thermal cleaned ones also. The activation energies of the phosphor are in the range 0.898 to 1.325 eV and frequency factors are in the order of 1011 to 1013 s−1.

Improving the Optical Properties of Potassium Chloride Crystals by Doping Diamond Nanoparticles

In this work, the growth and characterization of potassium chloride crystals containing diamond nanoparticles has been performed. The crystals were grown by the Czochralski method and the doped samples contained 0.5, 1 and 1.5% impurities of diamond nanoparticles. The crystals were characterized by X ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), etching and thermoluminesence (TL). The XRD analysis shows the most of the nanodiamonds are still in single crystal form. FTIR demonstrates the composed crystals are transparent in IR range (transmission ~ 87%). The etching analysis reveals a crystal dislocation in order of 105 for the samples. Examination of thermoluminescence properties of crystals by gamma irradiation with doses of 10, 80 and 300 Gy showed that the sample with 0.5% doped ND had the best glow curve, but for the dose of 1000 Gy, the sample with 1% doped had the best curve.

Green Afterglow of Undoped SrAl2O4

Undoped SrAl2O4 nanocrystals were obtained via solution combustion using urea as fuel. The afterglow properties of undoped SrAl2O4 were investigated. Green afterglow from undoped SrAl2O4 is visible to the human eye when the 325 nm irradiation of a helium–cadmium laser (13 mW) is ceased. The afterglow spectrum of undoped SrAl2O4 is peaked at about 520 nm. From the peak temperature (321 K) of the broad thermoluminescence glow curve, the trap depth of trap levels in undoped SrAl2O4 is estimated to be 0.642 eV using Urbach’s formula. Based on first-principles density functional calculations, the bandstructures and densities of states are derived for oxygen-deficient SrAl2O4 and strontium-deficient SrAl2O4, respectively. Our results demonstrate that the green afterglow of undoped SrAl2O4 originates from the midgap states introduced by oxygen and strontium vacancies. The observation of green afterglow from undoped SrAl2O4 helps in gaining new insight in exploring the afterglow mechanisms of SrAl2O4-based afterglow materials.

ANALYSIS OF THERMOLUMINESCENCE GLOW CURVES RECORDED UNDER THE HYPERBOLIC HEATING SCHEME BY USING AN ALTERNATIVE CONCEPT OF SYMMETRY

Usually, the order of kinetics of thermoluminescence (TL) glow curve is evaluated by using the concept of traditional symmetry factor (μ_g) in which only three points of a glow curve are used. From the statistical point of view of the reliability of any method of analysis of glow, curve improves if instead of a few points the method can use a larger portion of the glow curve. In the present work, a technique is proposed to determine the order of kinetics associated with a TL peak by using the concept of skewness. The method is applied to experimental thermoluminescence (TL) curves recorded in a hyperbolic heating scheme.