Glow Curve Analysis of Composite Peak 5 in LiF:Mg,Ti (TLD-100) Using Optical Bleaching, Thermal Annealing and Computerised Glow Curve Deconvolution

Abstract

The relative intensity of glow peak 5a in the composite glow peak 5 of LiF:Mg,Ti (TLD-100) is very weak following gamma irradiation, and has been estimated at approximately 0.1 of the intensity of peak 5. Typical glow curve analysis using computerised glow curve deconvolution with unconstrained variation of the peak shape parameters, yields values of the relative intensity of glow peak 5a varying from 0 to 15%. Due to the potential of peak 5a to fulfil the criteria of a quasi-tissue-equivalent nanodosemeter which estimates quality factor, considerable efforts have been invested in ancilliary techniques to improve the reliability of the estimation of the intensity of peak 5a. Optical bleaching and thermal annealing techniques were used to obtain single-peak glow curves consisting of peak 4 only and peak 5 only. A multi-stage CGCD protocol was then constructed using these peak shape parameters for peaks 4 and 5, which allows more accurate estimation of the relative intensity of peak 5a. Following 60Co irradiation of ten chips to a dose level of 1 Gy, the technique yields a relative intensity of 0.08 +/- 0.008 (1 SD).

Thermoluminescent composites of sintered synthetic-topaz/in situ corundum for dosimetry by a novel reversible process

“…Lithium fluoride (LiF) is the most studied material with dosimetric properties, being commercialized as a dosimeter in its TLD-100 form (7 % of 6 Li and 92.5 % of 7 Li) with magnesium and titanium impurities at 300 and 15 ppm, respectively. The glow curves of TLD-100 consist of 5 characteristic peaks (65, 120, 140, 195, and 210 °C), where the signal of peak 5 located up to 230 °C is widely used in dosimetry [ 48 ]. The maximum intensities in the glow curves of topaz/corundum composites sintered in this work are within the most appropriate range for dosimetric applications (160 and 250 °C) [ 49 ].…”

High-dose characterization of different LiF phosphors

“…2 illustrates separation of glow-curves measured after doses of 5 kGy into single peaks. The peaks were numbered according to the common convention, with the peak 5a at the high-temperature side of main peak 5 for LiF:Mg,Ti (one should note that some researchers call this peak 5b, while name 5a is used for another peak located at the low-temperature side of peak 5, Biderman et al, 2002). For MCP the consecutive numbers were attributed to the high-temperature peaks.…”

Localized transitions in the thermoluminescence of LiF : Mg,Ti: potential for nanoscale dosimetry

“…The results of this procedure following He ion irradiation are shown in figure 7 [19] and constituted the first convincing evidence for the composite nature of peak 5. As previously mentioned, peak 5a is not readily observed following gamma irradiation but computerized glow curve deconvolution employing strictly controlled analysis protocols and using ancilliary thermal and optical bleaching techniques to characterize and simplify the glow curve and its components has allowed the determination of the relative intensity following gamma ray irradiation at 0.08 ± 0.008 (1 SD) [20]. Computerized glow curve analysis indicates that the relative intensity of peak 5a to peak 5 following 1 MeV amu −1 He ion irradiation is 0.34 ± 0.04 (1 SD) [20].…”