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[en] A scheme is presented for calculating confidence contours for the parameters of the saturating exponential function fitted to experimental TL-dose data. The contours are accurate but, because of the non-linearity of the function, the corresponding probabilities are not. The conditions for obtaining good precision without excessive effort are explored. A reasonable prescription is six equally-spaced doses, with the largest about six times the intercept on the TL-dose plot, and with eight and seven replicates at the lowest doses of the first- and second-glow data sets respectively, and two replicates at all other doses. (author)
[en] Thermoluminescence (TL) properties of sphene and epidote are of interest in studies related to their radiation damage. Natural and artificially induced TL of these minerals has, therefore, been investigated. Both minerals exhibit complex glow curves with several overlapping peaks. The Tsub(m) -Tsub(STOP) thermal cleaning procedure has revealed three peaks in the γ ray induced glow curve of each mineral. That these peaks obey second order kinetics was indicated by the continuously slanting structure of the Tsub(m)-Tsub(STOP) curve. The TL parameters E and s have been calculated using (i) the initial rise method, and (ii) the glow-peak shape method. In general, the values of E calculated by the first method are found to be higher than those from the second. The TL curve-fitting method is also applied in order to calculate these parameters and to serve as a cross-check on the results. (author)
[en] This paper exploits the possibility of using commercial software for thermoluminescence and optically stimulated luminescence curve deconvolution analysis. The widely used software package Microsoft Excel, with the Solver utility has been used to perform deconvolution analysis to both experimental and reference glow curves resulted from the Glow Curve Analysis Intercomparison project. The simple interface of this programme combined with the powerful Solver utility, allows the analysis of complex stimulated luminescence curves into their components and the evaluation of the associated luminescence parameters. (authors)
[en] Highlights: • The impact of non-fulfillment of the SP theorem on the CGCD analysis was discussed. • TL glow curves were simulated over a wide range of doses and different conditions. • In general, the non-fulfillment of the SP theorem has no effect on the CGCD method. The analysis of complex thermoluminescence (TL) glow curves in its individual peaks is achieved by a computerized glow curve deconvolution (CGCD). The correct application of the CGCD requires the fulfillment of the superposition principle (SP), which postulates that the TL peaks have to be independent of each other. In the present work we simulate the application of the CGCD using interactive phenomenological models in which the SP is not fulfilled. The thermoluminescence (TL) processes of four active traps and one thermally disconnected deep trap (TDDT) was simulated over a wide range of doses and under different competition cases. The TL glow-curves were analyzed by the CGCD algorithm and the accuracy of the kinetic parameters and the dose dependence of each trap were investigated over the doses. In most of the simulated cases, the non-fulfillment of the superposition principles has no significant effect on the accuracy of the computed kinetics parameters. Different behaviors of dose response curve were discussed including sub-linear and supra-linear dose dependence. It has been also found that in the case of presence of competitions among the active traps, an almost linear dose response curve can be observed for the last glow-peak in a series of overlapping glow-peaks.
[en] Lyoluminescence dosimetry is based upon light emission during dissolution of previously irradiated dosimetric materials. The lyoluminescence signal is expressed in the dissolution glow curve. These curves begin, depending on the dissolution system, with a high peak followed by an exponentially decreasing intensity. System parameters that influence the graph of the dissolution glow curve, are, for example, injection speed, temperature and pH value of the solution and the design of the dissolution cell. The initial peak does not significantly correlate with the absorbed dose, it is mainly an effect of the injection. The decay of the curve consists of two exponential components: one fast and one slow. The components depend on the absorbed dose and the dosimetric materials used. In particular, the slow component correlates with the absorbed dose. In contrast to the fast component the argument of the exponential function of the slow component is independent of the dosimetric materials investigated: trehalose, glucose and mannitol. The maximum value, following the peak of the curve, and the integral light output are a measure of the absorbed dose. The reason for the different light outputs of various dosimetric materials after irradiation with the same dose is the differing solubility. The character of the dissolution glow curves is the same following irradiation with photons, electrons or neutrons. (author)
[en] While recording the natural thermoluminescence (TL) of a feldspar (Amelia albite) it has been found that if the heating is not sufficient to clean out the high-temperature peak which occurs around 550-5750C, a new peak at about 3000C occurs on the next heating. This new observation of regeneration of TL is different from the regenerated TL reported in the literature, and seems to be due to a localized, thermally assisted mechanism. (author)
[en] An overview of the successes and failure of the computerized glow curve deconvolution (CGCD) and the peak shape methods in describing the glow peaks generated from the fundamental one trap-one recombination center (OTOR) model was discussed. Also, the existing method, and a new developed one, to test the applicability of the existing thermoluminescence (TL) expressions to describe the glow peaks were discussed. The new TL expressions deduced by Kitis and Vlachos ( G. Kitis, N.D. Vlachos, Radiat. Meas. 48 (2013) 47–54) were tested in the cases in which the other existing TL expressions failed. The results showed that the error in the calculated activation energy (E) using the existing expressions may reach up, in some cases, to 50%. While, using the new TL expressions, the error in the calculated E did not exceed 0.5%. -- Highlights: • The successes and failure of the CGCD and peak shape methods were discussed. • The deduced TL expressions based on the Lambert W function were tested. • A comparison between the existing and the new deduced TL expressions was made. • The error of E calculated using the existing expressions may reach up to 50%. • The error of E calculated using the new deduced expression did not exceed 0.5%
[en] The thermoluminescence of quartz sampled at various depths in the KTB-drill hole was studied. The trapping parameters, such as activation energy, frequency factor and kinetic order, were determined by different methods: peak shift with heating rate; initial rise; peak shape; isothermal decay. Lifetimes were calculated assuming first-order kinetics. The results are compared among the different methods and with values reported by other authors. (author)
[en] The kinetics usually employed for analyzing glow curves are either heuristic or derived from physical models resorting to approximations. In this article closed expressions for the interactive and non interactive multi-trap models are derived without approximations, which render the analysis of glow curves more reliable.