An ultrahigh spatial resolution radiation-imaging detector using 0.1 mm × 0.1 mm pixelated GAGG plate combined with 1 mm channel size Si-PM array

Spatial resolution of a pixelated scintillator-based radiation-imaging detector is sometimes limited by the pixel size of the scintillators. We developed a small-size pixelated GAGG scintillator using a dicing method and combined it with a small channel-size Si-PM array for the development of an ultrahigh resolution radiation-imaging detector. The developed pixelated GAGG scintillator had a pixel size of 0.1 mm × 0.1 mm arranged in 0.15-mm separations. It was combined with a Si-PM array made of 1 mm × 1 mm channels to form a radiation-imaging detector. With the developed radiation imaging detectors, the 0.1 mm × 0.1 mm pixels could be resolved for Am-241 alpha particles (5.5 MeV). The spatial resolutions of this imaging detector were better than 0.31-mm FWHM for Am-241 alpha particles and Ca-45 (maximum energy: 0.257 MeV) beta particles. The spatial resolutions for Am-241 gamma photons (60 keV) and Cs-137 X-ray (∼32 keV) were better than 0.6-mm FWHM. Separation of the images of alpha particles and gamma photons was possible using the scintillation decay time difference of GAGG between alpha particles and gamma photons. The developed ultrahigh spatial resolution pixelated GAGG radiation-imaging detector is promising for the imaging of alpha particles, beta particles, low-energy gamma photons and X-ray.