Comparison of the beveled-edge and reach-through APD structures for PET applications

The electrical characteristics of the beveled-edge and reach-through APD structures are theoretically and experimentally analyzed to determine which is most suitable for incorporation into a Positron Emission Tomography (PET) detector. The beveled edge structure is found to have a lower excess noise factor and lower dark current, leading to a superior signal-to-noise ratio. The reach-through structure is found to have a lower operating voltage and faster speed of response. Because signal-to-noise ratio is fundamentally important to achieving the energy and timing resolutions required for PET detectors, we believe the beveled-edge Structure is more appropriate than the reach-through structure for PET applications. This finding is experimentally verified by comparing the performance of several commercially available beveled-edge and reach-through APDs.<
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