Effect of Ga Substitution in a (Ce,Lu)(3)Al5O12 scintillator was examined at the crystals grown by the micro-pulling down(mu-PD) method. Strong suppression of unwanted host luminescence due to an exciton localized around Lu-Al antisite defect was observed even at the Ga concentration of 10 mol%. Less-intense slower components in scintillation decay were obtained upon increasing the amount of Ga. While the radioluminescence intensities of the 5d-4f luminescence of Ce3+ were not strongly changed, light yield was increased by Ga substitution. The 20% Ga-substituted sample showed even higher light yield than typical Czochralski-grown Ga-free LuAG:Ce. (C) 2008 Elsevier B.V. All rights reserved.