Source motion compensated coded aperture imaging using thick 3D-position-sensitive CdZnTe detectors

The 18 - detector array system consists of eighteen 20mm × 20mm × 15mm CdZnTe detectors. In addition to spectroscopic capabilities, it has the ability to image gamma-ray sources with energies above 200keV in 4-pi space via Compton imaging. To extend the imaging capabilities to lower energies, two coded aperture masks have been applied to the system. In a practical scenario, the source could be moving in relation to the detector system. The resultant coded aperture images formed will be blurred and distorted unless this source movement is considered in the system model. This motion can be used to our advantage in the case of an imperfect detector and mask configuration with image artifacts. By averaging the images from multiple positions, the image intensity in the source direction will be unaffected, while the artifacts will be reduced significantly. In theory, this motion compensated image will not only reduce the fluctuations due to non-uniformity of the detector material properties, but will also flatten the image side-lobes caused by the random mask design, thus improving the signal-to-noise ratio of the source peak to background in the reconstructed image. The focus of this research is to validate this claim through measurement and simulation, and to ultimately automate this process given the coordinates and direction of the source.