Influence of neutron irradiation and its post-annealing on optical absorption of rutile

Abstract

The influence of neutron irradiation and its post-annealing on optical absorption of rutile single crystal has been investigated. Rutile TiO 2 (1 1 0) specimens were cut from the same crystal, and were irradiated with high-fluence (i.e. 1×10 19 cm −2) neutron irradiation, then annealed in vacuum and oxidization atmosphere at different temperature, respectively. After irradiation, the sample shows deep blue-dark color. After oxidization, it becomes transparent again. But annealed in vacuum, it keeps color invariable. By means of UV–VIS–IR, laser Raman spectroscopy (LRS) and X-ray diffraction (XRD), samples were investigated before and after neutron irradiation, as well as after annealing. The results show neutron irradiation induces wide, strong optical absorption plateau in the 600–2500 nm region. After the sample was annealed in an oxidization atmosphere, the absorption plateau splits into several absorption peaks. But after the sample is annealed in vacuum, the plateaus almost unchanged. Combining with LRS and XRD measurement results, the formation mechanism of the optical absorption band is also discussed.