## 3 Results and Discussion
### TL Slow Curve  
The area under the TL glow curve represents luminescence emission over the effective temperature range that elicits dose-dependent trap emptying. Rich in detail, it provides information on TL yield, trap depth and signal fading properties of the materials. Ideally, the TL dosimeter should have glow peak temperatures that are sufficiently great to avoid large-scale fading while at the same time avoiding infrared heating cavity emission issues. In particular, for retrospective dosimetry one is seeking high thermal stability (i.e., deep-seated electron traps) that provide for useful dose storage, even extending over periods from perhaps a number of weeks to some several months or years. Figure 2 shows typical glow curves obtained from the windshields of the three brands of vehicle, each sample being irradiated to a test dose of 10 Gy. All the samples reveal a broad curve, peaking between 354-389 \({}^{\circ}\)C. The behaviour is common to a number of the previously cited amorphous media that have been investigated for TL dosimetry, the distribution of energy showing none of the signs of discreteness seen for instance in ordered media such as TLD-100. Herein, the peaks have been observed to occur at temperatures well above 250 \({}^{\circ}\)C, indicative of samples providing high thermal stability, reflective of deep trapping, an essential requirement for dose reconstruction in retrospective dosimetric applications [1]. As seen in Figure 2, the TL glow peak of the Proton sample displays two peaks, a dominant high-intensity peak at 389 nm and a low-intensity peak at 280 nm: a peak at 389 nm displays-17 times larger than the intensity at the peak of 280 nm. Notably, due to its excellent signal stability, the high intensity peak was significant for dosimetry study; hence, this study focuses primarily on the obtained pronounced peaks. At the various doses, the TL glow curves have been shown to be of identical structure in repeat cycles of annealing and irradiation. The estimation of three fundamental parameters such as the kinetic order, frequency factor (s), and activation energy (E) can be obtained via the analysis of the shape and size of TL glow peaks. In obtaining the order of kinetic, the geometric factor (\(\mu_{g}\)) was first determined using peak shape method developed by [PERSON] [21] as follows:  
\[\mu_{g}=\ \frac{\delta}{\omega}=\ \frac{T_{2}-T_{M}}{T_{2}-T_{1}} \tag{3}\]  
where, \(T_{M}=\) temperature at which the maximum TL intensity occur, \(T_{1}\) and \(T_{2}=\) temperatures on either side of \(T_{M}\), corresponding to half-intensity, \(\delta=T_{2}-T_{M}\), half width at the high temperature side, \(\omega=T_{2}-T_{1}\), the full width at half maximum (FWHM). By substituting the required values in the aforementioned expression, the geometric factor (\(\mu_{g}\)) for all brands windscreens are found to be between 0.48 and 0.51 (see Table 3), indicating that the recombination process for all samples were within the second-order kinetics. The activation energy (E) is further obtained by using the general expressions given by [PERSON] [21], which is valid for any order of kinetics. The activation energy was calculated using the Equation (4):  
\[\mathrm{E}\ =\ C_{\alpha}\ \frac{kT_{M}^{2}}{\alpha}\ -\ \mathrm{b}_{\alpha}\ (2 \mathrm{k}T_{M}) \tag{4}\]  
here \(\alpha\) can be either \(\delta\) or \(\omega\). The values of \(\mathrm{C}_{\alpha}\) and \(\mathrm{b}_{\alpha}\) are obtained using the following expressions:  
\[\mathrm{C}_{\delta} =0.976+7.3\ (\mu_{g}-0.42);\ \mathrm{b}_{\delta}=0\] \[\mathrm{C}_{\omega} =2.52+10.2\ (\mu_{g}-0.42);\ \mathrm{b}_{\omega}=1\]Upon obtaining the values of the activation energy, the frequency factor (s) for the windshield car brands can be calculated using the formula in Equation (5) [21];  
\[\text{s}\ =\ \frac{\beta E}{kT_{M}^{2}}\exp(\frac{E}{kT_{M}}) \tag{5}\]  
where \(\beta\) is the heating rate that employed in this present study (10 K s\({}^{-1}\)) and k is the Boltzmann constant (\(8.62\times 10^{-5}\)) eV\(\cdot\)K\({}^{-1}\).