Thermoluminescence (TL) is basically a super-sensitive phenomenon exhibit ted practically by all semiconductors/ insulators upon suitable excitation. The occurrence of TL peaks during the thermal scan of a previously excited material gives rise to a number of peaks whose trapping parameters and relative concentrations can be evaluated by well-known techniques. Thus, TL in principle is a unique tool to characterize scintillator crystals. The technique is capable to detect the relative abundance of carriers in traps as shallow as ≈0.1eV to as deep as 2.0eV; providing means to probe carriers having lifetime (τ) as low as ∼ps to as large as billions of years. Hence the technique can be used to design scintillator materials of desired properties specially the decay time, the rise-time and the afterglow by adjusting the presence/absence of relevant trapping levels.