Sub-pixel Sensing for Pixelated CdZnTe Detectors

These Pixelated CZT detectors are capable of providing 3-D position information of gamma-ray interactions within one detector volume. It is a key performance parameter for Compton imaging or coded aperture applications [12]. The lateral position resolution of CZT detectors using pixelated anodes is limited by the pixel pitch. In the pixelated CZT detector design at University of Michigan, the pixel pitch is 1.72 mm. As a comparison, the depth sensing technique based on the cathode-to-anode ratio [1] can give about 0.5 mm depth resolution [10]. It is much more precise than the pixel pitch. The relatively poor lateral position resolution limits the Compton image angular resolution to roughly 40 degrees FWHM using simple back-projection reconstruction [13]. For coded aperture imaging, the impact is more significant [14].