In this work, we present results of structural characterization and optical properties including radio luminescence of (LuxGdyY0.99-x-yTm0.01)AP single crystal scintillators for (x, y) = (C.30, 0.19), (0, 0.19) and (0, 0) grown by the micro-pulling-down (mu-PD) method. The grown crystals were single phase materials with perovskite structure (Pbnm) as confirmed by XRD and had a good crystallinity. The distribution of the crystal constituents in growth direction was evaluated, and significant segregation of Lu and Gd was detected in (Lu0.30Gd0.19Y0.50Tm0.01)AP sample. The crystals demonstrated 70% transmittance in visible wavelength range and some absorption bands due to Tm3+, Gd3+ and color centers were exhibited in 190-900 nm. The radioluminescence measurement under X-ray irradiation demonstrated several emission peaks ascribed to 4f-4f transitions of Tm3+ and Gd3+. The ratio of emission intensity in longer wavelength range was increased when Y was replaced by Lu or Gd. (C) 2012 Elsevier Ltd. All rights reserved.