SCINTILLATION PROPERTIES OF CERIUM-DOPED GADOLINIUM SCANDIUM ALUMINUM GARNETS

Optical properties and scintillation responses of cerium doped gadolinium-scandium-aluminum garnets (GSAG), pulled by the Czochralski method, were studied with regard to applications in scintillation counters. Scintillation responses were investigated for irradiation with charged particles, gamma-rays and neutrons. The observed decay constant (tau = 120 ns) is shorter than in common inorganic scintillators like NaI(Tl) and bismuth germanate (BGO). The attenuation coefficient exceeds the value reported for NaI(Tl). GSAG(Ce) shows a higher light yield (30% when compared with Nal(Tl)) and better energy resolution (12.5% for 662 keV gamma-rays from Cs-137) than BGO. To demonstrate the feasibility for neutron detection, crystals were irradiated with slow neutrons (from 14.7 meV to 120 meV) from a neutron diffraction spectrometer at the Grenoble pile Melusine and fast neutrons (greater-than-or-equal-to 7.9 MeV) from the Stuttgart Dynamitron accelerator using the Be-9(alpha, n) C-12 reaction.