Performance comparison of two signal multiplexing readouts for SiPM-based pet detector

PET scanners using SiPMs as photodetectors could have tens of thousands of SiPMs. To simplify the readout electronics, analog signal multiplexing readouts are always preferred to be used as early as possible. In this paper, two simple analog signal multiplexing readouts, a capacitive charge-division readout, and a resistive charge-division readout were evaluated and compared using dual-ended readout detectors based on 10  ×  10 arrays of SensL MicroFJ-30035 SiPMs coupled to both ends of a 20  ×  20 LYSO array with a pitch size of 1.5 mm and a length of 20 mm. The performance of the detectors were evaluated at different bias voltages (from 27.0 V to 30.5 V with an interval of 0.5 V) and a temperature of 22.8 °C. The flood histograms show that all the crystals in the LYSO array were clearly identified, whilst better flood histogram was obtained using the resistive charge-division readout. At a bias voltage of 29.5V, the flood histogram quality, energy resolution, DOI resolution, and timing resolution of the detector obtained using the capacitive charge-division readout were 3.28  ±  0.85, 18.9%  ±  6.2%, 1.93  ±  0.20 mm, 1.25  ±  0.11 ns respectively, and those obtained using the resistive charge-division readout were 3.57  ±  0.81, 16.9%  ±  6.5%, 1.96  ±  0.23 mm and 1.23  ±  0.07 ns, respectively. Overall, the detector with the resistive charge-division readout provided better performance.