Radiation response of transition metals-doped lithium aluminate crystals

Abstract

Basic radiation response properties of lithium aluminate LiAlO₂ crystals activated with transition metals like Ti, Mn and Cu were examined. When X-ray excited the crystals, intense emission peaks were observed at visible wavelength regions, they are ascribed to the Ti⁴⁺ charge transfer (Ti-doped), Mn²⁺ 3d⁵-3d⁵ (Mn-doped) and Cu⁺ 3d⁹4s-3d¹⁰ (Cu-doped) transitions. The scintillation decay times were estimated to be about 1.8 μs (93 %) and 9.9 μs (7 %) for the Ti-doped crystal, 310 μs (96 %) and 2220 μs (4 %) for Mn-doped one, and 3.6 μs (52 %) and 19.6 μs (48 %) for Cu-doped one, respectively. In the ²⁵²Cf neutron irradiated pulse height spectra, Ti- and Cu- doped crystals showed higher light yield in comparison to that of GS20 commercial scintillator.