Basic study of Eu2+-doped garnet ceramic scintillator produced by spark plasma sintering

We report a new discovery of Eu2+-doped bulk garnet ceramic scintillators based on reduction of Eu3+ ions without additives. Eu2+-doped Y3Al5O12 and Lu3Al5O12 ceramics were prepared by spark plasma sintering (SPS) method. Using SPS, the green and blue luminescence was observed under UV lamp excitation for Eu2+-doped Y3Al5O12 and Lu3Al5O12 ceramics, respectively. Under excitation by Am-241 alpha-ray the Eu2+ 5d-4f emission was observed in radioluminescence spectra both samples. For the first time, scintillation response due to Eu2+ 5d-4f luminescence was observed in the bulk garnet oxide materials. In addition, Eu-doped Al2O3 prepared by SPS showed Eu2+ 5d-4f emission in the radioluminescence spectrum. It is confirmed that Al is a key element to reduce Eu3+ as well as highly reductive condition in SPS. (C) 2012 Elsevier B.V. All rights reserved.