Radioluminescence of color centers in LiF crystals

Luminescence of color centers in the near-infrared region under cathode beam excitation is revealed for the first time in as-grown pure LiF and LiF:Mg,O crystals. Emission efficiency of F2+, F3− and F2−centers is higher for the samples enriched by oxygen and magnesium than for ultrapure crystals. The intensity of the NIR luminescence remains practically constant with the increase of the electron beam density. In contrast, visible emission typical for F3+and F2 centers is suppressed due to the induced absorption bands. It is assumed that the high-density electronic irradiation leads to the strongly pronounced thermal- and radiation-stimulated diffusion in a relatively thin layer. It causes the association of point radiation defects with the formation of various complex centers and aggregates. Results obtained suggest that LiF crystals can be used for in-situ detection of ionizing radiation. ► Color centers NIR emission is firstly revealed in LiF under the cathode excitation. ► F2+, F3− and F2− centers emission is higher for LiF:Mg,O than for pure LiF crystal. ► NIR emission intensity remains persistent with the increase of excitation density. ► Visible emission of F3+ and F2 and F2− centers is suppressed due to the induced absorption. ► Results obtained point to possibility of LiF for “in-situ” detection of radiation.