Thermoluminescence of LiF TLD-100: Glow-curve kinetics

Abstract

The thermoluminescence kinetics have been determined for the 13 glow peaks contained in the glow curves obtained from LiF TLD-100 after exposure to 60Co irradiations. The glow curves were constructed from measurements made with recently developed equipment for recording emission spectra at closely spaced temperature intervals. In addition, the recorded data has been subjected to all corrections needed to make it suitable for reliable kinetic analysis. The recorded emission spectra can be described by a single Gaussian-shaped band whose width and peak-energy parameters vary erratically with temperature or, alternatively, by resolving the observed spectra into three Gaussian-shaped bands whose parameters vary with temperatures in accord with theoretical expressions relating the emission-spectra peak energy and full width at half-maximum to the sample temperature. The kinetics and kinetic parameters were independently determined for the two most intense resolved emission bands. All peaks are described by first-order kinetics and the independently determined parameters are in very good agreement. The glow curves for the least intense component are also described by the same kinetics and parameters. Inasmuch as the single-band emission is a superposition of the three components, the same kinetics and parameters apply to the glow curve constructed from unresolved spectra. The identification number, nominal peak temperature in °C (for a heating rate of 10.3 °C/min), the activation energy E (eV), and preexponential factor s (sec−1) for the 13 peaks are as follows: (1) 1.62, 1.04, and 1014; (2) 94, 1.07, and 1013; (3a) 112, 0.987, and 1011; (3) 137, 1.05, and 1011; (4) 170, 1.54, and 4×1015; (5) 190, 2.20, and 1022; (5a) 210, 1.61, and 1015; (6) 235, 1.70, and 1015; (7) 260, 1.79, and 1015; (8) 285, 1.96, and 5×1015; (9) 315, 2.10, and 1016; (10) 345, 2.19, and 1016; (11) 370, 2.27, and 1016. The unusual value of s=1022 for the 190 °C peak, previously reported by other authors, was obtained during this study. However, it appears that this value can be obtained from relatively simple mechanisms and one of these is described.

Similarities and differences between two different types of the thermoluminescence dosimeters belonging to the LiF family

“…Thereby, at low dose levels and under the usual annealing procedures, the interference from peak 4 accounts the greater problem. On the other hand, the existence of peak 5a was originally introduced by Fairchild et al [33], as a requirement to obtain a good fit to the experimental glow-curve of TLD . However, Gartia and Sing [34] and Abd El-Hafez et al [3] ignored this glow-peak in their analysis procedures.…”

“…These peaks were referred as peaks 5a and 6. Peak 5a was originally introduced by Fairchild et al [33]. Kitis and Otto [36] concluded that this peak cannot seen in the usual glow-curve, resulting after the normal annealing.…”

Recent Advances in Silica Glass Optical Fiber for Dosimetry Applications

“…The model described with two energy levels is the simplest model that can be used to explain thermoluminescence but obviously is not sufficient to describe thermoluminescence from a real TL material at least because it cannot predict the presence of the several TL peaks in the material glow curve observed in the most popular TLDs, an instance being LiF with four glow peaks. Experimental observations have suggested the existence of a range of trapping and recombination [24], [25] as can be seen schematically in Fig. 2 above.…”

Applications of the three points analysis method for obtaining the trap parameters and the separation of thermoluminescence glow curve into its components

“…The last parameter to be obtained is the relative value of n o (cm −3 ). Usually, n o is not evaluated by using one of the analytical methods, but instead, n o is taken either to be proportional to I m or proportional to the area under the peak, [1,18,26,27]. However, instead of using the peak height or peak area, an analytical method has been developed to obtain the relative value of n o in case of general-order glow peak, by inserting equation (16) into equation (6).…”