Development and hybrid imaging performance evaluation of a 4π-FoV Compton camera based on spherical detector system

摘要: Gamma-ray imaging plays a crucial role in source-term monitoring and consequence management of nuclear power plants. These applications typically involve mapping of complex spatial distributions consisting of various radioactive isotopes, and coverage of large areas through free-moving measurements. This requires the imaging equipment to achieve not only an 4π field-of-view (FoV), but also an isotropic response within the FoV across a wide energy range. To resolve these issues, we designed and implemented a spherical detector system functioning as a Compton camera with an isotropic FoV and active coded aperture imaging capabilities. This camera system adopts Cerium-doped Gd3A2Ga3O12 (Ce:GAGG) scintillator detectors and a multichannel electronics system utilizing application specific integrated circuit (ASIC). Besides Compton imaging, a modified hybrid gamma-ray imaging approach is developed to combine Compton and active coded aperture imaging capabilities, which was not fully explored in previous research. Through systematic evaluations of Compton, coded aperture and hybrid imaging, we have verified that the modified hybrid imaging method can provide enhanced imaging resolution and sensitivity, along with an extended energy range. By applying the modified hybrid imaging technique, the developed camera system achieves fine imaging performance, making it well-suited for application in free-moving 3-D radiation mapping.