The Measurement of Activator Concentration Using an X-Ray Fluorescence Method for Cr Ions in Al2O3 Crystals as an Example

Abstract—A method for measuring the concentration of Cr3+ ions is considered in ruby single crystals (Al2O3 : Cr3+) using X-ray fluorescence analysis. The laboratory energy dispersive spectrometer was calibrated using the external standard method for quantitative measurements. In constructing the calibration dependence, we used a series of test samples of ruby crystals in which the concentration of Cr3+ ions was determined from the spectra of the long-wavelength U absorption band of ruby with a maximum in the region of 550 nm. The linear dependence of the X-ray fluorescence intensity on the concentration of chromium ions was obtained, which indicates the absence of matrix effects in the studied range of Cr3+ concentrations (from 0.01 to 0.8 wt %). The possibility of using the method for measuring the concentration of other activators in dielectric ionic crystals is noted.