On extending the applicability of the initial rise method for thermoluminescence glow peak analysis

Abstract

We discuss an approach by which the initial rise (IR) method can be extended to evaluate the frequency factor (s) of a glow peak, in addition to activation energy (E) that is usually obtainable from it. The approach requires that the phosphor be irradiated to a dose near or equal to the saturation dose of the glow peak to be analyzed. By plotting ln(I) against 1/T for the thermoluminescence glow peak, one obtains a straight line whose gradient is − E/k and intercept is ln(n 0 s/β) from which E and s are determined respectively. The approach was used to analyze two numerically generated glow peaks and reproduce with reasonably good accuracy the E and s values used to generate the glow peaks. It is also shown that when it becomes necessary to include intensities above 10% of the maximum glow peak intensity, the error introduced into the calculated frequency factor by the assumption n≅ n 0 is always negligible when the analysis is done by plotting ln(I/n) against 1/T. In this case the frequency factor is obtained from ln(s/β) which is now the intercept. Two experimental glow peaks were also analyzed using the new IR method approach and peak shape method. Good agreement, which again shows the validity and reliability of the present approach was observed between the values of E and s obtained by the two methods.