Ion beam modification of colorless silicates of beryl

The optical and electronic properties of beryl (Be3Al2Si6O18) are very sensitive to the presence of impurities in the crystal. Ion implantation of Fe, Mn, Cr and V was carried out on natural colorless beryl crystals to study modification of these properties. Ion implantation was performed with energy of 400 keV at room temperature for all samples. For Fe, Mn and Cr the implanted dose was 2×1016 ions/cm2 and for V it was 9×1015 ions/cm2. Electron paramagnetic resonance (EPR), optical absorption (OA) and thermoluminescence (TL) techniques were used to study the behavior of the samples after ion implantation. The measurements were carried out for γ-irradiated and non-irradiated samples. The results have shown that after ion implantation and annealing, in most cases, the ions occupy interstitial positions and positions in the channels of the crystal. The optical absorption spectra showed an increase for Fe2+ and two new bands in the visible region (at approx. 540 and 410 nm).