Sensitivity of LiF : Mg, Ti thermoluminescence detectors after various annealing procedures

doi:10.1016/S0168-583X(97)00487-4

Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms

Volume 132, Issue 4, 1 December 1997, Pages 639-646

https://doi.org/10.1016/S0168-583X(97)00487-4 Get rights and content

Abstract

The extensively studied impact of the thermal treatment on the LiF : Mg, Ti glow-curve structure is attributed to the clustering and precipitation of the Mg impurities, according to the reaction sequence; Free Mg²⁺V⁻ ⇋ dipoles ⇋ trimers ⇋ precipitates. Experimentally, this reaction is investigated by increasing the ageing temperature from room temperature up to 400° C. In the present work this reaction is examined toward its opposite direction, i.e. by decreasing the ageing temperature from 400°C to room temperature. Under this thermal treatment the sensitivity of the main glow-peak 5 is reduced by 60%, whereas the sensitivities of the glow-peak 2–4 are stable between 400°C and 200°C and then drop rapidly by a factor of 3, 5.5 and 1.53, respectively. A separate experiment was performed, which showed that during the readout precipitates are not formed.

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Cited by (2)

Thermoluminescence response of various dosimeters as a function of irradiation temperature
2020, Radiation Physics and Chemistry
Citation Excerpt :
As for the TLD-600, there is an increase in the intensity of the high temperature peaks by 120%, whereas the MTS-700 peaks increase by 25%. Table 2 is presented for two different reasons: a) to show all the kinetic parameters that were yielded according to the deconvolution analysis, including the activation energy, the Tm values and the frequency factor S; as these are already known by previous studies (Kitis and Tuyn (1997); Kitis and Otto (2000); Sadek et al. (2017)), the agreement with the bibliography is an additional indicator that the analysis of the current study is trustworthy, b) to compare the aforementioned features between the two LiF families. Having in mind these two reasons, Table 2 shows that the activation energies of all 8 peaks of the Harhsaw LiF family are the same throughout the entire annealing temperature range.
The behavior of various TL dosimeters following two different thermal treatments with temperature ranging between 50 and 230 °C, was investigated in this particular study. The thermal treatment consists of two different protocols, including a simultaneous irradiation-heating and a post irradiation heating. The dosimeters that are the subject of the present study include two different families of lithium fluorides, namely the Harhsaw LiF family (TLD-600, TLD-700), LiF of the Krakow university (MTS-600, MTS-700), BeO and the commonly used CaSO₄ samples with two different impurities (Dy and Tm). According to the analysis, it seems that the TLDs and MTS-600 are identical with regard to their characteristics, while MTS-700 is different. The treatment showed that the intensities of peak 5 of all LiF samples increases up to 20–30% at 110 °C which is followed by a decrease, while the high temperature peaks of LiF showed a high dependence on the treatment temperatures. As for the case of BeO, one peak has a minor increase of 10% at 80–90 °C and a decrease up to 230%, while the other is stable. CaSO₄ samples show no increase and there is a decrease starting at 150 °C. Also, this work studied the kinetic parameters of all peaks for these samples via the computerized glow curve deconvolution method. In the end, there is a categorization of the LiF samples based on their properties and their glow curves. Lastly, the results indicate that the lack of strong increase of the TL response with increasing irradiation temperature for the majority of the TL peaks of these aforementioned phosphors does not support strong competition effects. A notable exception is observed for the high temperature TL peaks in all LiF samples regardless of whether these were purchased from Harshaw or from Poland.
Peculiarities of the glow-peak 5a of LiF:Mg,Ti
2000, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
The glow-peak 5a of LiF:Mg,Ti is a glow-peak, with peak maximum temperature between those of glow-peaks 5 and 6. This glow-peak is not seen in the usual glow-curve, resulting after normal annealing at 400°C for 1 h and at 100°C for 2 h. However, its existence is confirmed first experimentally and then as the necessity to achieve a very good glow-curve fitting. In the present work it is found that the glow-peak 5a can be very well isolated from its neighbouring glow-peaks, after special thermal treatment between 140°C and 160°C. The isolation permits the study of its individual behaviour, which was found to have the following peculiarities. (i) This glow-peak is clearly seen only after thermal treatment between 140°C and 160°C. (ii) It appears with the same properties after both pre-irradiation and post-irradiation annealing in the above temperature region. (iii) Its activation energy was found to be above 3 eV and its frequency factor above 10³⁰ s⁻¹. These values are extremely high and outside the physically accepted limits.

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Sensitivity of LiF : Mg, Ti thermoluminescence detectors after various annealing procedures

Abstract

Nucl. Instr. and Meth.

Nucl. Instr. and Meth. B

Phys. Status Solidi A

Health Phys.

J. Phys. D

J. Phys. D

J. Phys. D

Radiat. Prot. Dosim.

Radiat. Prot. Dosim.