Comparison of UV-IR radioluminescence and cathodoluminescence spectra of a potassium feldspar

This paper reports on the cathodoluminescence (CL) and radioluminescence (RL) emission properties of well-characterised K-rich feldspar (K0.98Na0.02Al1.02Si2.98O8)(K0.98Na0.02Al1.02Si2.98O8). Both CL and RL spectra display three groups of components in the: (i) UV (290 nm); (ii) green (570 nm) and (iii) red-IR (640 nm) region. As observed in other aluminosilicates, the emission peaked at lower wavelengths (290 nm) can be associated with structural defects located in the twin-domain boundaries related to the recombination process in which the Na+Na+ ion diffusion-limited is involved; green and red emissions are, respectively, associated with the presence of Mn2+Mn2+ and Fe3+Fe3+ ions. The ratio between the relative intensities peaked at 290 and 570 nm is about 3:7 for CL and 1:7 for RL; this fact indicates that the efficiency of recombination centres changes depending on the type of radiation, i.e., X-rays to obtain the RL spectra and electron beams for the CL emission.