Transparent ceramic scintillators for gamma spectroscopy and MeV imaging

Abstract

We report on the development of two new mechanically rugged, high light yield transparent ceramic scintillators: (1) Ce-doped Gd-garnet for gamma spectroscopy, and (2) Eu-doped Gd-Lu-bixbyite for radiography. GYGAG(Ce) garnet transparent ceramics offer ρ = 5.8g/cm³, Z_eff = 48, principal decay of <100 ns, and light yield of 50,000 Ph/MeV. Gdgarnet ceramic scintillators offer the best energy resolution of any oxide scintillator, as good as R(662 keV) = 3% (Si-PD readout) for small sizes and typically R(662 keV) < 5% for cubic inch sizes. For radiography, the bixbyite transparent ceramic scintillator, (Gd,Lu,Eu)₂O₃, or “GLO,” offers excellent x-ray stopping, with ρ = 9.1 g/cm³ and Z_eff = 68. Several 10” diameter by 0.1” thickness GLO scintillators have been fabricated. GLO outperforms scintillator glass for high energy radiography, due to higher light yield (55,000 Ph/MeV) and better stopping, while providing spatial resolution of >8 lp/mm.