Elucidating the effect of intrinsic defects on the dosimetric properties of the MgB₄O₇compound: an atomistic simulation approach

Abstract

MgB4O7 has attracted much attention for dosimetric applications in recent years, for reasons including its low effective atomic number and large bandgap to accommodate charge carrier traps. Particularly, the charge...

Unlocking the effect of Li and Ce ions on the thermoluminescence and optically stimulated luminescence signals of the MgB4O7 compound

“…For that, we have used the set of potential parameters developed and validated in ref. 14. It was used as a strategy to obtain the potential parameters, the Buckingham and Morse potentials, and the ionic polarizability model.…”

“…8 In a previous work, we showed that the MgO anti-Schottky type defect is the most probable in MgB 4 O 7 and we hypothesised that the TL and OSL emissions observed in the pure matrix occur due to the presence of these defects. 14 According to us, it is likely that during the MgB 4 O 7 synthesis process, at temperatures of 400 °C, MgO absorbs oxygen from the atmosphere, which acts as an electron acceptor, eliminating the F s , F s + and F s 2+ centres, and forming O 2 − , O 2 2− , O − and O 2− that can diffuse into the material.…”

“…The total energy ( E T ) can be obtained by the expression E T = E 1 ( x ) + E 12 ( x , u ) + E 2 ( u ), where E 1 ( x ) is the energy of region I, E 2 ( u ) is the energy of region II, and E 12 ( x,u ) is the energy of the interaction region between them. To obtain the defect energies, we have used a set of potential parameters developed and validated by Contassot et al 14 It was used as a strategy to obtain the Buckingham and Morse potential parameters and the ionic polarizability model and to infer different characteristics of magnesium tetraborate. Readers interested in more details about the potentials are directed to ref.…”

“…Recently, our group published results showing the mechanism of spontaneous diffusion of interstitial Mg and O into the crystal lattice as associated with the relatively weak, but existent, TL and OSL emissions from the undoped MgB 4 O 7 . 14 However, the role of Li ion doping and co-doping MgB 4 O 7 at different concentrations to enhance the luminescence signal remains unclear in the literature and has become an obstacle to the design of more efficient dosimeters.…”

“…In this context, we combined experimental and computational methodologies to demonstrate the influence of lithium incorporation in MgB 4 O 7 – with and without Ce ions. With the set of interatomic potentials used in our quoted work 14 – connected to an atomistic simulation approach – X-ray diffraction (XRD), thermal analysis (DTA/TG), Particle-Induced X-ray Emission (PIXE), TL, and OSL measurements – it was possible to perform a deeper analysis on the role of Li incorporation in changing the luminescence properties of the MgB 4 O 7 compound.…”