A Spherical Active Coded Aperture for 4\pi Gamma-Ray Imaging

Gamma-ray imaging facilitates the efficient detection, characterization, and localization of compact radioactive sources in cluttered environments. Fieldable detector systems employing active planar coded apertures have demonstrated broad energy sensitivity via both coded aperture and Compton imaging modalities. However, planar configurations suffer from a limited field of view, especially in the coded aperture mode. To improve upon this limitation, we introduce a novel design by rearranging the detectors into an active coded spherical configuration, resulting in a 4π isotropic field of view for both coded aperture and Compton imaging. This paper focuses on the low-energy coded aperture modality and the optimization techniques used to determine the optimal number and configuration of 1-cm 3 CdZnTe coplanar grid detectors on a 14-cm diameter sphere with 192 available detector locations.