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3D-position-sensitive CdZnTe semiconductor detectors have demonstrated 4ʌ Compton imaging capability and excellent energy resolution at room-temperature operation. However, Compton gamma-ray imaging is not feasible at low energies due to the small Compton-scatter cross-section. This work extends the current imaging capabilities to lower energies by utilizing coded aperture masks. Multiple coded aperture masks are applied to a single detector system of four 20mm×20mm×15mm CdZnTe detectors.Near-4ʌ coded aperture imaging has been demonstrated through Monte Carlo simulation. The correct source direction is consistently identified using measured data with one mask above the cathode side and another mask above the non-cathode side of the detector. Challenges related to electric field distortion due to space charge in the detector are discussed. The focus of this research is to image near-4ʌ field of view using coded apertures, ultimately, combining both Compton and coded aperture imaging techniques to expand the range of gamma-ray imaging.

Abstraet-3D position sensitive CdZnTe semiconductor detectors have demonstrated 4n Compton imaging ability and excellent energy resolution at room-temperature operation. An array of such detectors would provide unique detection capabilities. However, Compton imaging is challenging at low energies due to the small Compton-scatter cross-section. This work extends the imaging capabilities to lower energies by utilizing multiple coded aperture masks.Each coded aperture mask is applied to one of five sides of a single 2cmx2cmxl.5cm CdZnTe detector via simulation. These simulations show that multiple weak, low energy sources with background can be imaged simultaneously. The ultimate objective is to apply multiple masks to cover 4n space, using an 18 detector array from the Polaris project.

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