Performance of a SiPM Readout ASIC Chip MPT2321

MPT2321 is a 32-channel application-specific integrated circuit (ASIC) for silicon photomultiplier (SiPM), featuring high signal-to-noise ratio (SNR) and energy resolution, along with outstanding timing performance. Particularly for single-photon signals, the chip maintains a considerably high SNR. This article describes the fundamental architecture and key performance parameters of the chip. A series of measurements was conducted to evaluate the charge and time detection performance. First, the timing jitters of the analog and analog–digital mixed parts of the chip were measured by external charge injection. Then, a single photon spectrum was acquired by irradiating the SiPM (Hamamatsu S15639-1325PS, $1.3\times 1.1$ mm, and pixel pitch of $25~\mu $ m) with a high-precision pulsed laser, revealing clearly distinguishable peaks. Meanwhile, factors affecting timing jitter were also analyzed. Additionally, by utilizing light emitting diode (LED) emission, the single-photon spectra of different single-photon avalanche diode (SPAD) sizes (25, 35, and $40~\mu $ m) were presented. Finally, the energy resolution was measured to be 8.7% $\pm ~0.1$ % full width at half maximum (FWHM) at 511 keV using SiPM (Hamamatsu S14160-6050HS, $6\times 6$ mm) coupled with lutetium yttrium oxyorthosilicate (LYSO) crystals ( $4\times 4\times 20$ mm). With time walk correction, a coincidence time resolution (CTR) of $289~\pm ~6$ ps (FWHM) was achieved. Based on the results of these performance measurements, MPT2321 has been verified to be a qualified candidate for applications in several fields.