Performance comparison between ceramic Ce:GAGG and single crystal Ce:GAGG with digital-SiPM

The Gd3Al2Ga3O12 (Ce: GAGG) is a new inorganic scintillator known for its attractive properties such as high light yield, stopping power and relatively fast decay time. In this study, we fabricated a ceramic Ce: GAGG scintillator as a cost-effective alternative to single crystal Ce: GAGG and, for the first time, investigated their performances when coupled to the digital silicon photomultiplier (dSiPM) - a new type of photosensor designed for applications in medical imaging, high energy and astrophysics. Compared to 3 x 3 x 2mm(3) sized single crystal Ce: GAGG, the translucent ceramic Ce: GAGG, which has a much lower transmittance than the single crystal, was determined to give an output signal amplitude that is approximately 61% of single crystal Ce: GAGG. The energy resolution of the 511 keV annihilation peak of a Na-22 source was measured to be 9.9 +/- 0.2% and 13.0 +/- 0.3% for the single and ceramic scintillators respectively. On the other hand, the coincidence resolving time (CRT) of ceramic Ce: GAGG was 307 +/- 23 ps, better than the 465 +/- 37 ps acquired with single crystals -probably attributed to its slightly faster decay time and higher proportion of the fast decay component. The ceramic Ce: GAGG may be a promising cost-effective candidate for applications that do not require thick scintillators such as x-ray detectors and charged particle detectors, and those that require time-of-flight capabilities.