Performance comparison of steering-grid and simple-pixel CdZnTe detectors

Pixellated CdZnTe detectors have shown its potential to provide excellent spectroscopic performance at University of Michigan. To minimize charge loss in the gap between pixels, steering grid was used on standard Polaris CdZnTe detectors. Steering grid is biased and placed between pixels to force electrons to drift to anode pixels so that they won't be trapped in the gap. Such design is proven to be effective in improving the energy resolution of multi-pixel-triggered events. But on the other side biased steering grid increases the leakage current on pixels and complicates the detector fabrication. Therefore, detectors without steering grid (simple-pixel detectors) are investigated to see if they can provide similar performance as steering-grid detectors. This study has shown that simple-pixel detectors can provide similar spectroscopic performance of standard Polaris CdZnTe detectors using steering grid. The improvement on sub-pixel position resolution because of this design change is also reported.