W. Shambhunath Singh

On the mixed order kinetics of the thermoluminescence glow peak

The shape factor of a thermoluminescence (TL) glow peak following mixed order (MO) kinetics has been reinvestigated. A modification of the existing equation of MO kinetics to include the filling factor , where is the initial concentration of trapped electrons and N is the concentration of the electron trap sites) has been proposed. The shifting of peak temperature for a MO kinetics peak with the change of filling factor and hence the irradiation dose absorbed by the sample is reported. A new set of expressions for the evaluation of the activation energy of a TL peak in the light of MO kinetics is presented. The applicability of the MO kinetics model is reported by fitting both the numerically simulated glow peak and the experimentally observed peak of -irradiated NaCl:I and x-irradiated BeO.

Modified peak shape method for the determination of activation energy in thermoluminescence

We have reconsidered the peak shape method in thermoluminescence by taking into account the main difficulty of the peak shape method, i.e. the dependence of the symmetry factor μ g on um (=E/kTm ) , where E is the activation energy, Tm is the peak temperature and k is the Boltzmann constant. In the present paper, the peak shape method is improved by taking into account this dependence. Finally, the applicability of the present findings has been analyzed by considering both synthetic and experimental thermoluminescence curves including glow curves of the most common dosimetric material LiF : Mg, Ti (TLD-100). It is also found that activation energies as calculated by the present method are in good agreement with those calculated by the rigorous method of curve fitting.

Activation energy of thermoluminescence glow curves in a hyperbolic heating scheme

We present a set of expressions for the determination of the activation energy of a thermoluminescence peak recorded with a hyperbolic heating scheme. It is demonstrated that the order of kinetics can be estimated from the fractional intensities at the points of inflection of the peak.

Activation Energies and Temperature Dependent Frequency Factors in Thermoluminescence Recorded with Hyperbolic Heating Scheme

A method has been developed for the evaluation of activation energy of thermoluminescence peak recorded with hyperbolic heating scheme by taking into account temperature dependent frequency factor. We have arrived at a number of expressions of activation energy involving the peak temperature and/or temperatures corresponding to the two points of inflection of the peak. It has been observed that the temperature dependence of frequency factor might lead to an error of the order of 10% in the determination of activation energy.