Development of a high-precision color gamma-ray image sensor based on TSV-MPPC and diced scintillator arrays

We developed a high-precision color gamma-ray image sensor with fine spatial resolution that is cost effective, widely applicable, and very sensitive, by using a diced Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) scintillator array coupled with a 3.0×3.0 mm2/pixel 8×8 MPPC-array. The proposed image sensor can measure the energy of individual X-ray photons transmitted through an object. The pixel size of the Ce:GAGG scintillator array is 0.2 mm, and the pixels are separated by 50-μm-wide micro-grooves. The image sensor has an area of 20×20 mm2 and a thickness of 1.0 mm, and it achieves an excellent spatial resolution of 0.3-0.4 mm and energy resolutions of 12% and 18% (FWHM) for 122 and 59.5 keV gamma-rays, respectively. We conducted an experiment to determine the local effective atomic number of metals using dual-energy gamma-ray sources. In addition, we developed a color-composite image using mixed images taken at three energies (31, 59.5, and 88 keV).