Radiation hardness of LuAG:Ce and LuAG:Pr scintillator crystals

Single crystals of LuAG:Ce, LuAG:Pr and un-doped LuAG were grown by the vertical Bridgman method and studied for radiation hardness under gamma-rays with doses in the range 10–105 Gy (60Co). A wide absorption band peaking at around 600 nm springs up in all three types of crystals after the irradiations. The second band peaking at around 375 nm appears in both LuAG:Pr and un-doped LuAG. Compositional variations have been done to reveal the spectral behavior of induced color centers in more detail and to understand their origin. Similarities in behavior of Yb2+ centers in as-grown garnets are found, indicating that radiation induced color centers can be associated with residual trace amounts of Yb present in the raw materials. Un-doped LuAG and LuAG:Ce demonstrate moderate radiation hardness (the induced absorption coefficients being equal to 0.05–0.08 cm−1 for accumulated doses of 103–104 Gy), while LuAG:Pr is less radiation hard. The ways to improve the radiation hardness are discussed.

► Radiation hardness of LuAG:Ce and LuAG:Pr single crystals was examined.
► The role of residual impurities was analyzed.
► Importance of the purity control in respect to Yb has been demonstrated.