Attenuation characteristics of a Ce:Gd3Al2Ga3O12 scintillator

Attenuation characteristics of scintillation photons from Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) scintillators were investigated by measuring samples of various sizes. Scintillation light is attenuated by two factors. The first is self-absorption of the Ce:GAGG scintillator itself, and the second is geometrical effects such as reflection properties caused by reflector wrapping. The attenuation coefficient of the Ce:GAGGs was determined as 0.00155±0.00006 mm −1 indicating that the scintillation light decays to 1/e as it passes approximately 645 ± 26 mm through the Ce:GAGG. This attenuation does not affect the entire wavelength range; however, it significantly occurs only in the wavelength range from 460 nm to 510 nm where emission and absorption overlap. In the narrow Ce:GAGG scintillator used in this experiment, the geometrical attenuation effect was in the overall wavelength, and the attenuation coefficient was 0.010 ± 0.001 mm −1. In this setup, the self-absorption effect only occupied 10% of the whole attenuation, while geometrical attenuation significantly affected the number of detected photons.