Application of scintillators based on single-crystalline Lu₃Al₅O₁₂:Ce³⁺ films for radiation monitoring in biology and medicine

Abstract

Possibility of producing screens of X-ray detectors using liquid phase epitaxy on Y₃Al₅O₁₂ substrates covered by Lu₃Al₅O₁₂:Ce single crystalline films (SCF) is studied. Optical, luminescent and luminous characteristics of these SCF doped with isoelectronic La, Y, Sc impurities are analyzed. The possibility of crystallization of Lu₃Al₅O₁₂: Ce SCF on Y₃Al₅O₁₂ substrates by means of matching the lattice parameters of these garnets, when Lu³⁺ ions in Al³⁺ octa-sites, is proved. With the aim of matching the emission spectra of SCF based on Lu₃Al₅O₁₂: Ce, with the spectral sensitivity range of radiation detectors – CCD cameras – we investigated SCF containing Gd³⁺, Tb³⁺, and Eu³⁺ impurities. The maximum light yield, exceeding that of analogs based on Y₃Al₅O₁₂:Ce SCF by the factor of 1.1-1.5, is shown to be intrinsic for Lu₃Al₅O₁₂:Ce³⁺, Lu₃Al₅O₁₂:Ce, Y, La and Lu₃Al₅O₁₂:Ce, Tb SCF. An increase of the effective atomic number Zeff and density r up to the values of 60.6 and 7.35 g/cm³ respectively, enables the efficiency of X-ray absorption in comparison with Y₃Al₅O₁₂:Ce³⁺ SCF by the factor of 2.5–8 higher and to reach spatial resolution not less than 0.75–1.0 µm at the SCF thickness of 1.0–2.0 mm.