Luminescent properties of MgB4O7:Ce,Li to be applied in radiation dosimetry

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

“…In most works involving Ce-doped and Li-co-doped MgB 4 O 7 materials, the nominal Li concentration is higher than the Ce concentration. 6,7,12,54,55 However, according to some authors, part of the Li amount is lost during synthesis, and the amount of Li in the final product is considerably lower than the concentration of Li added to the initial solution. 6,9 For this reason, even with Li concentrations of 10%, the phases involving Li are not observed in X-ray diffractograms, as expected in materials with Li concentration of this order of magnitude.…”

“…In general, the concentration of efficient dopants is varied to modify the amount of activating sites in the host matrix, in view of finding the optimal amount to obtain improvement in characteristics such as the OSL/TL emission intensity and the dose-response linearity range, for example. [6][7][8] One example of a material that has been analysed experimentally, considering its dosimetric potentiality, is MgB 4 O 7 :Ce,Li. In this case, the incorporation of Li into the host matrix leads to a drastic change in the OSL signal depending on the Li and Ce concentrations.…”

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

“…where N s is the intrinsic defect concentration (defects.cm À3 ), n A is the Avogadro number (mol À1 ), r is the density of the crystal (g cm À3 ), M is the molar mass of the compound (g mol À1 ), Edef is the defect formation energy (eV), k is Boltzmann's constant (eV K À1 ) and T is the temperature (K). The concentration of defects at 298 K, resulting from MgO anti-Schottky disorder, is 3.798 Â 10 22 defects per cm 3 . Considering that the unit cell volume of MgB 4 O 7 is 9.834 Â 10 À22 cm 3 , the number of defects per unit cell is 37.35 at 298 K. Fig.…”

“…The ion's charge is defined by summing the core and shell charges. Eqn (3) shows the shell-model potential, where k is the harmonic constant and is defined by the ratio between the square of Y (shell charge) and a (polarizability). k and Y are obtained through a fitting procedure.…”

“…More recently, several studies have been published on MgB 4 O 7 :Ce co-doped with alkali metals such as Li and Na, analysing its thermoluminescence (TL) emission and mainly due to its optically stimulated luminescence (OSL) signal characteristics. [2][3][4][5][6] Regarding specific aspects of this emission, it remains a challenge to fully understand the effect of, for example, the addition of alkali to the Ce-doped matrix, which results in a considerable increase in the signal.…”