Sub-pixel position resolution in pixelated semiconductor detectors

Experimental data collected from an 18×18×11 mm
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3-dimensional mercuric iodide detector demonstrate methods of measuring sub-pixel gamma-interaction position within a single anode pixel volume. Present work focuses on algorithms that make use of charge induced on non-collecting adjacent pixels. These estimations of sub-pixel position in the x and y directions are based on ratios of opposing neighbor pixel signals. Digital signal processing, including digital filter functions and filter variables optimized to measure the shape of transient signals, allow accurate measurements of information needed to estimate sub-pixel position. An edge collimator is used to block different areas of a collecting pixel to demonstrate the proposed methods.