A Diode-Based Symmetric Charge Division Circuit With Grounding Path to Reduce Signal Crosstalk and Improve Detector Performance

Multiplexing circuits in pixelated PET detectors are being studied with the goal of minimizing the degradation of detector performance. The purpose of this study was to develop a diode-based symmetric charge division (SCD) circuit with reducing the crosstalk caused by the leakage currents of adjacent channels connected in rows and columns. Four different SCD circuits (diode-based SCD with grounding path, diode-based SCD, resistor-based SCD with grounding path, and resistor-based SCD) were constructed and their performance was evaluated and compared after being combined with a PET detector consisting of Lutetium Yttrium Orthosilicate crystals optically coupled with SiPM. The diode-based SCD circuit with grounding path achieved a crosstalk ratio, energy resolution, coincidence timing resolution (CTR), and mean peak to valley ratio of 0.02, 14.3%, 0.5 ns, and 27.9: 1, respectively; the diode-based SCD circuit achieved 0.03, 15.9%, 0.7 ns, and 19.4: 1, respectively; the resistor-based SCD circuit with grounding path achieved 0.04, 14.5%, 0.9 ns, and 19.4: 1, respectively; and the resistor-based SCD circuit achieved 0.05, 17.8%, 1.8 ns, and 17.7: 1, respectively. These results indicate that the proposed SCD has the potential to improve not only the crosstalk but also the energy linearity, energy resolution, and CTR characteristics in PET detectors.