A monolithic ASIC demonstrator for the Thin Time-of-Flight PET scanner

Time-of-flight measurement is an important advancement in PET scanners to improve image reconstruction with a lower delivered radiation dose. This article describes the monolithic ASIC for the TT-PET project, a novel idea for a high-precision PET scanner for small animals. The chip uses a SiGe Bi-CMOS process for timing measurements, integrating a fully-depleted pixel matrix with a low-power BJT-based front-end per channel, integrated on the same 100 $\mu{} m$ thick die. The target timing resolution is 30 ps RMS for electrons from the conversion of 511 keV photons. A novel synchronization scheme using a patent-pending TDC is used to allow the synchronization of 1.6 million channels across almost 2000 different chips at picosecond-level. A full-featured demonstrator chip with a 3x10 matrix of 500x500 $\mu{} m^{2}$ pixels was produced to validate each block. Its design and experimental results are presented here.