Abstract:
The kinetic analysis of thermoluminescence of beta-irradiated SrAl2O4:Eu2þ,Dy3þ is reported. The glowcurve
is dominated by an apparently-single peak. It has been demonstrated using a number of tests
including partial dynamic-heating, isothermal heating, phosphorescence and, the effect of fading, that
the peak and the glow-curve consists of a set of closely-spaced peaks. In view of the peak being complex,
its first few components were abstracted and analysed and for comparison, the peak was also analysed
assuming it is genuinely single. In the latter, the order of kinetics is calculated to be intermediate between
first and second-order and not first-order as predicted by qualitative tests such as the Tm Tstop or
Tm dose procedures. A model based on density of energy states has been used to account for and
reconcile the qualitative and quantitative results. The activation energy is found as ~1 eV, consistent with
the value expected of Dy2þ, the presumed electron trapping state of the Dy3þ electron trap. The thermoluminescence
is subject to thermal quenching with an activation energy of 0:520±0:002 eV. The
luminescence is ascribed to 5d/4f7 Eu2þ transitions whereas the thermal quenching is presumed to
occur from an alternative level of the degenerate 5d energy level of the Eu2þ cation.
