Application of thermal treatment of zircon for the interpretation of luminescence centers

The photoluminescence (PL) of zircon is characterized by a broad structureless spectral band down to 4.6 K, which does not enable correct interpretation of the nature of the luminescence centres (LC). By applying step-like thermal treatment, a radiation treatment and timeresolved spectroscopy, seven pure bands were separated and their individual spectral-kinetic properties were determined. The yellow PL is connected with three LC: 1. Intrinsic defects of the (SiO_m)^n- type, which are generated by radioactive decay of U and Th; 2. Impurity defects (MeO_m)^n- (Me-Mo, V) associated with charge compensators, probably the Fe³⁺ and Ti³⁺ (clusters of these LC generate a yellow-orange shoulder); 3. Impurity defects (UO₂)²⁺. The blue PL is connected with impurity defects (TiO_m)^n-. The red PL is connected with impurities Fe³⁺ and Ti³⁺. These LC are characterized by a different thermal stability and response to ionizing irradiation. This work allows us to propose some practical applications in the fields of dating, dosimetry and genetical mineralogy.