Zircon steady-state spectra

Thorite and orangite (orange thorite) have a tetragonal structure and are isostructural with zircon. Steady-state spectra under X-ray and laser (337 nm) excitations are connected with REE " ", namely Sm " ", Tb ", Dy " " and Eu ". Reabsorption lines of Nd " have been also detected (Gorobets and Rogojine 2001). Laser-induced time-resolved luminescence enables us to detect Eu " and uranyl emission centers (Eig. 4.70). 

Luminescence of Pr + in zircon is very difficult to detect under UV excitation even by time-resolved spectroscopy. The reason is that it has a relatively short decay time similar to those of radiation-induced centers. Visible excitation, which is not effective for broadband luminescence, allows the revealing of Pr + luminescence lines, using high-resolution steady-state spectroscopy. Under such experimental conditions each element has individual lines, enabling confident identification of the spectrum to be possible (Gaft et al. 2000a). Only if radiation-induced luminescence in zircon is relatively weak, the lines of Pr may be detected by UV excitation (Fig. 4.38c). 

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