Thermoluminescence Glow Curve Deconvolution Research Articles

Gamma irradiated Er3+ ions doped Li2O–BaO–B2O3–P2O5 glasses: Structural, optical, and thermoluminescence glow curve analysis

Lithium barium borophosphate glasses doped with Er3+ rare earth ions are reported in terms of their physical, optical, structural, and thermoluminescence (TL) properties in this study. The melt quenching method was used to synthesize the glasses with varying concentration of the dopant (0.0, 0.2, 0.4 0.6, 0.8 and 1.0 mol%). A thorough analysis of physical characteristics, including their variation with erbium oxide, has been conducted. The amorphous phase of the as-quenched samples has been validated through X-ray diffraction patterns, while Fourier transform infrared spectroscopy confirmed the existence of different structural groups. UV–Vis–NIR spectroscopy at wavelengths ranging from 200 to 1100 nm has been utilized to investigate various optical properties. In the gamma dose range of 50 Gy to 10 kGy, the glass sample with 0.6 mol% of erbium concentration (LBPEr0.6) showed the maximum integrated TL intensity with an optimized heating rate of 5 °C/s and annealing temperature of 400 °C. The deconvolution of TL glow curves was done using the R-package “tgcd: Thermoluminescence Glow Curve Deconvolution" by employing the Kitis general order kinetics model. Chen's peak shape approach has been used to calculate the trapping parameters, including order of kinetics (b), shape factor (μg), frequency factor (s), and activation energy (E). The ideal thermoluminescence dosimeter characteristics showed that LBPEr0.6 glass has outstanding linearity, excellent sensitivity, minimal fading and good reproducibility over six cycles.

Study of the thermoluminescence properties of γ and UV-C irradiated Li3PO4: Dy synthesized by solid state diffusion method

This paper reports the thermoluminescence (TL) properties of Li3PO4 doped with rare earth Dy3+ ions. The solid state diffusion method is used to synthesize phosphors with varying concentrations of the dopant (0.1, 0.2, 0.3, 0.4 and 0.5 mol%). Characterization of the samples is performed using X-ray diffraction (XRD), Fourier Transform Infrared-Attenuated Total Reflection spectroscopy (FTIR-ATR) and Scanning Electron Microscopy (SEM). Samples are irradiated with γ rays in the dose range of 10 Gy to 6 kGy and by UV-C rays (254 nm) for exposure duration ranging from 0.5 to 5 h. Maximum TL intensity in both cases is observed for the phosphor doped with 0.2 mol% Dy3+. While a linear TL response is found for the entire duration of UV-C irradiation, the dose response for γ irradiation stays linear upto 3 kGy for the high temperature peak at 335∘C. Appreciable repeatability values are found (for both γ and UV-C irradiated samples) and significantly low fading (for the UV-C irradiated phosphor) is reported. The computerized glow curve deconvolution has been done using an R-package, “tgcd: Thermoluminescence Glow Curve Deconvolution” by assuming the Kitis general order kinetics model. Chen’s peak shape method is utilized to extract trapping parameters such as the order of kinetics (b), shape factor (μg), frequency factor (s), activation energy (E) and trap density (n0). Various promising properties of this material are found suggesting that it could be used as a TL dosimeter.

The kinetic parameters of the main thermoluminescence glow peak of Al2O3:C,Mg: A critical evaluation of different analytical methods

Carbon and magnesium co-doped aluminum oxide (Al2O3:C,Mg) is a highly sensitive luminescence dosimeter with promising use in a wide spectrum of radiation-related applications, including neutron dosimetry and as a fluorescent nuclear track detector (FNTD). The goal of this work is to critically evaluate diverse methods and approaches for the determination of the kinetic parameters using Al2O3:C, Mg as a case study. Al2O3:C, Mg was beta irradiated with doses from 0.1 to 0.6 Gy. Besides thermoluminescence (TL) peaks at 325, 350, and 375 K, the analysis of the activation energy, frequency factor and order of kinetics focused exclusively on the main TL peak at 450 K. Analysis by curve fittings used a number of freeware, namely, Glowfit, TLAnal, the Thermoluminescence Glow Curve Deconvolution (TGCD) package, and the spreadsheet TLDecoxcel. The results from the computational approaches were compared with results obtained by analyzing experimental data using conventional methods as initial-rise, whole glow peak, variable heating rate and peak shape. The performance of the computational methods is satisfactory as the values found are consistent with the ones determined by the methods listed above.

A new thermoluminescence mixed order model considering thermal ‎quenching effect

Thermal quenching as an important and well-known effect in compounds exhibiting thermoluminescence, should be considered in thermoluminescence studies. Among the models describing the thermoluminescence phenomenon, the mixed order kinetic model provides a more realistic description of this behavior. In this work, the Thermal quenching effect is included in the mixed order kinetic model and the new thermoluminescence glow curve deconvolution function is obtained in terms of the maximum intensity and the maximum intensity temperature. The new equation reduces to the known mixed order model by equating the thermal quenching parameter to zero. Also the kinetic parameters of the peak 5 of LiF: Mg, Ti (TLD-100) thermoluminescence dosimeter considering the new equation (with Thermal quenching effect) and the previous equation (without Thermal quenching effect) for different heating rates are determined and the results are compared.

Thermoluminescence glow curve deconvolution for discrete and continuous trap distributions

Deconvolution analysis of the thermoluminiscent (TL) glow curves proved to be a good complementary method to characterize the individual glow peaks by fitting their kinetic parameters. In this work, new software has been developed for the automatic deconvolution of TL glow curves, assuming either discrete or continuous distribution of trapping centres. The guess estimation of the kinetic parameters is done automatically and can be manually modified, thus allowing the use of the software for routine, processing a large number of measurements, as well as for research purposes. The equations, the methods and the results of the first test are described in detail. The software has been developed by integrating Fortran code and Visual Studio tools to create a graphic easy-to-use environment and permits to obtain the fitted values for the parameters according to the considered model.

New handling of thermoluminescence glow curve deconvolution expressions for different kinetic orders based on OTOR model

The exact equations of the thermoluminescence (TL) glow curve deconvolution that describe the intensity of a single TL glow peak of different order kinetics, which are obtained from the one trap-one recombination (OTOR) level model, are considered. The reformulation of the expressions of the intensities of TL glow peaks in terms of the peak intensity IM, peak position TM, and the activation energy ∈, for each order of kinetics are achieved. The authors developed a MATLAB computer code, which utilizes the obtained equations, to computationally deconvolute the TL glow curves. The code is used to investigate the reference glow curves of the GLOCANIN program. The obtained results agree with those previously reported by the GLOCANIN project with better values of the figure of merits FOM. The considerations of the obtained equations show promising trends to understand a peak formation for different order kinetics that belong to the OTOR level model.

Comment on the paper “Thermoluminescence glow-curve deconvolution functions for mixed order of kinetics and continuous trap distribution by G. Kitis, J.M. Gomez-Ros, Nuclear Instruments and Methods in Physics Research A 440, 2000, pp 224–231”

The present comment concerns the correct presentation of an algorithm proposed in the above paper for the glow-curve deconvolution in the case of continuous distribution of trapping states. Since most researchers would use directly the proposed algorithm as published, they should be notified of its correct formulation during the fitting of TL glow curves of materials with continuous trap distribution using this Equation.

Thermoluminescence of LaAlO3:C crystals grown by different mixing methodologies applied to UV dosimetry

In this paper, thermoluminescence (TL) properties such as glow curves analysis, dose response linearity and some dosimetric characteristics of pure and carbon doped lanthanum aluminate (LaAlO3) produced by different syntheses using the solid state reaction method are investigated, after exposure to different UV radiation doses. The effect of different syntheses on the TL glow curves structures is also investigated and discussed. TL glow-curve deconvolution (CGD) methods and the Chen’s peak shape methods were used to analyze the sets of TL glow curves. The kinetic parameters of TL single peaks were computed. Additionally, the life times (τ) of electrons in trap for all samples were determined and calculated. A good linear dose response over the dose range from 0.21 to 1.26mJ/cm2 has been attributed to both samples (B and C).

Thermoluminescence glow curve deconvolution of LiF:Mg,Cu,Si with more realistic kinetic models

Thermoluminescence (TL) glow curves of LiF:Mg,Cu,Si were deconvoluted with the introduction of enhanced physical model which envisages that both electrons and holes, produced by ionization radiation and trapped at the respective traps, can be thermally released into the conduction and the valence band, respectively and the holes may also radiatively recombine with electrons at the electron recombination centers. The model is more generalized than the ordinary trap interaction model which only permits the traffic of electrons through the conduction band. An effective numerical analysis method was developed to calculate the glow curve to be compatible with the measured curves. The validity of the numerical method was verified through artificially generated TL glow curves for a wide range of trap parameters. In order to identify TL kinetics of LiF:Mg,Cu,Si with higher accuracy, its glow curves were deconvoluted for two more generalized models, namely, the Schön–Klasens model and the Chen–Pagonis–Lawless model as well as the ordinary trap interactive model. The parameters in the more generalized multi-trap multi-recombination center (MTMR) model were found to be consistent with the quasi-static approximation(QSA) method.

Thermoluminescence glow curve deconvolution functions by continued fractions for different orders of kinetics

The shape of the peaks in thermoluminescence (TL) dosimetry can be represented by the so-called temperature integral. In this paper, we present a very efficient method, based on a continued fraction approach to the incomplete gamma function, intended to calculate the overall temperature integral which includes the frequency factor ∝ T a . The single glow-peak algorithm for linear and exponential heating rates is derived. In the first case, the method provides a good approximation with a maximum relative error of 1.1×10−5 within the 0.1≤E/kT≤90 range in the case of a=0. It is shown that, in general, the method is efficient, converges quickly and can be adopted in the numerical fitting of glow lines in order to obtain the parameters relevant to TL. The utility of this approach is exemplified by adjusting the standard lithium flouride doped with magnesium and titanium (LiF): Mg, Ti (TLD-100) using five and six thermoluminescent peaks, determining that peak 6 is present and observable in the analysed spectrum. Finally, methods such as asymptotic expansion of the temperature integral by the asymptotic series approximation, the convergent series approximation, the Lagrange continued fraction approximation and a new obtained continued fraction approximation are compared with the method proposed here in the case of linear heating.

Thermoluminescence glow curve deconvolution functions by continued fractions for different orders of kinetics

The shape of the peaks in thermoluminescence (TL) dosimetry can be represented by the so-called temperature integral. In this article, we present a very efficient method, based on a continued fraction approach to the incomplete gamma function, intended to calculate the overall temperature integral which includes the frequency factor ∝ T a . The single glow-peak algorithm for linear and exponential heating rates is derived. In the first case, the method provides a good approximation with a maximum relative error of 1.1×10−5 within the 0.1≤E/kT≤90 range in the case of a=0. It is shown that, in general, the method is efficient, converges quickly and can be adopted in the numerical fitting of glow lines in order to obtain the parameters relevant to thermoluminescence (TL). The utility of this approach is exemplified by adjusting the standard LiF: Mg, Ti (TLD-100) using five and six TL peaks, determining that peak 6 is present and observable in the analysed spectrum. Finally, methods such as asymptotic expansion of the temperature integral by asymptotic series, convergent series, Lagrange continued fractions and a new obtained continued fraction approximations are compared to the method proposed here, in case of linear heating.

Computerized glow curve deconvolution of thermoluminescent emission from polyminerals of Jamaica Mexican flower

The aim of this work is to study the main thermoluminescence (TL) characteristics of the inorganic polyminerals extracted from dehydrated Jamaica flower or roselle (Hibiscus sabdariffa L.) belonging to Malvaceae family of Mexican origin. TL emission properties of the polymineral fraction in powder were studied using the initial rise (IR) method. The complex structure and kinetic parameters of the glow curves have been analysed accurately using the computerized glow curve deconvolution (CGCD) assuming an exponential distribution of trapping levels. The extension of the IR method to the case of a continuous and exponential distribution of traps is reported, such as the derivation of the TL glow curve deconvolution functions for continuous trap distribution. CGCD is performed both in the case of frequency factor, s, temperature independent, and in the case with the s function of temperature.

Thermoluminescence glow curve deconvolution and its statistical analysis using the flexibility of spreadsheet programs

Analysing thermoluminescence glow curves involves the solving of a system of non-linear equations. These equations are either differential equations that must be solved numerically or functional approximations for their solution. The current paper presents software with the functions needed for the study of glow curves that is not a stand-alone computer program but an extension of MS Excel. It supplies functions that solve the general one trap model for the thermoluminescence process without the use of approximating functions. Combined with the Solver utility of Excel this gives a very flexible system for the analysis of glow curves. Functions for analysing the statistics of the deconvolution results are included.

On the possibility of using commercial software packages for thermoluminescence glow curve deconvolution analysis.

This paper explores the possibility of using commercial software for thermoluminescence glow curve deconvolution (GCD) analysis. The program PEAKFIT has been used to perform GCD analysis of complex glow curves of quartz and dosimetric materials. First-order TL peaks were represented successfully using the Weibull distribution function. Second-order and general-order TL peaks were represented accurately by using the Logistic asymmetric functions with varying symmetry parameters. Analytical expressions were derived for determining the energy E from the parameters of the Logistic asymmetric functions. The accuracy of these analytical expressions for E was tested for a wide variety of kinetic parameters and was found to be comparable to the commonly used expressions in the TL literature. The effectiveness of fit of the analytical functions used here was tested using the figure of merit (FOM) and was found to be comparable to the accuracy of recently published GCD expressions for first- and general-order kinetics.

Fit of second order thermoluminescence glow peaks using the logistic distribution function.

A new thermoluminescence glow curve deconvolution (GCD) function is introduced which accurately describes second order thermoluminescence (TL) curves. The logistic asymmetric (LA) statistical probability function is used with the function variables being the maximum peak intensity (Im), the temperature of the maximum peak intensity (Tm) and the LA width parameter a2. An analytical expression is derived from which the activation energy E can be calculated as a function of Tm and the LA width parameter a2 with an accuracy of 2% or better. The accuracy of the fit was tested for E values ranging from 0.7 to 2.5 eV, for s values between 10(5) and 10(25) s(-1), and for trap occupation numbers no/N between 1 and 10(-6). The goodness of fit of the logistic asymmetric function is described by the Figure of Merit (FOM) which is found to be of the order of 10(-2). Preliminary results show that the GCD described here can easily be extended to the description of general order TL glow curves by varying the asymmetry parameter of the logistic asymmetric function. It is concluded that the TL kinetic analysis of first, second and general order TL glow curves can be performed with high accuracy and speed by using commercially available statistical packages that incorporate the Weibull and logistic asymmetric functions.

Fit of first order thermoluminescence glow peaks using the Weibull distribution function.

A new thermoluminescence glow curve deconvolution (GCD) function is introduced which accurately describes first order thermoluminescence (TL) curves. The new GCD function is found to be accurate for first order TL peaks with a wide variety of the values of the TL kinetic parameters E and s. The 3-parameter Weibull probability function is used with the function variables being the maximum peak intensity (Im), the temperature of the maximum peak intensity (Tm) and the Weibull width parameter b. An analytical expression is derived from which the activation energy E can be calculated as a function of Tm and the Weibull width parameter b. The accuracy of the Weibull fit was tested using the ten reference glow curves of the GLOCANIN intercomparison program and the Weibull distribution was found to be highly effective in describing both single and complex TL glow curves. The goodness of fit of the Weibull function is described by the Figure of Merit (FOM) which is found to be of comparable accuracy to the best FOM values of the GLOCANIN program. The FOM values are also comparable to the FOM values obtained using the recently published GCD functions of Kitis et al. It is found that the TL kinetic analysis of complex first-order TL glow curves can be performed with high accuracy and speed by using commercially available software packages.

Thermoluminescence glow-curve deconvolution functions for first, second and general orders of kinetics

Thermoluminescence glow-curve deconvolution (GCD) functions are proposed for first, second and general orders of kinetics. The free parameters of the GCD functions are the maximum peak intensity and the maximum peak temperature , which can be obtained experimentally. The activation energy (E) and the order of kinetics (b) in the case of general order kinetics are the additional free parameters.