FastIC ASIC readout performance for Cherenkov based TOF-PET imaging

The emerging field of ultra-fast timing has enormous potential in high-energy physics, nuclear medicine, and imaging, and is driving advances in detector and readout electronics. To achieve improved time resolution, significant efforts have been devoted to this field, resulting in impressive coincidence time resolution (CTR) values for silicon photomultiplier (SiPM) and scintillator crystals using state-of-the-art high-frequency (HF) readout. However, scaling this readout method for system-level applications is not yet feasible, hence requiring dedicated application-specific integrated circuits (ASICs). In this study, we evaluate the performance of the FastIC, an 8-channel readout ASIC suitable for TOP-PET application, in terms of CTR. The study employs Cherenkov photons produced in bismuth germanium oxide (BGO) scintillator crystals and novel SiPMs with metal-trenching. We obtain CTR values of 257±5 ps and 152±4 ps, respectively, for 2x2x20mm³ and 2x2x3mm³ BGO crystals using HF readout as a reference, with minimal electronic interference, by exploiting the full potential of SiPMs with metal trenching. In comparison, the CTR values obtained using the FastIC for the same crystals were 490±3 ps and 330±4 ps, respectively. We also assess the limits of the FastIC and suggest areas for further improvements.