Improvement of ceramic YAG(Ce) scintillators to (YGd)3Al5O12(Ce) for gamma-ray detectors

Based on our successful development of ceramic Y3Al5O12(Ce) scintillators, we fabricated two samples of (YGd)(3)Al5O12(Ce) scintillator, to achieve higher stopping power to gamma-rays. They are both activated with Ce to a 0.5 mol% concentration, but differ in sintering conditions. We investigated their optical properties and gamma-ray responses. One of them showed a poor (similar to 1%) optical transparency at 550 nm, while the other had a much improved (similar to 20%) transmission. They both showed a dominant decay constant of similar to 90 ns, when irradiated with gamma-rays. The more transparent one exhibited light yield which is similar to 30% of that of ceramic YAG(Ce), and similar to 14% (FWHM) energy resolution at 662 keV when coupled with a phototube. When coupled with an avalanche photo diode, it exhibited similar to 8% energy resolution at the same energy. The stopping power of the new ceramics was confirmed to be five times as high as that of YAG(Ce) at similar to 660keV, by counting detected photo-absorption events. (c) 2007 Elsevier B.V. All rights reserved.